From 1931666b046016893e44a8b595980964363e1e6a Mon Sep 17 00:00:00 2001 From: Luke Wren Date: Sat, 5 Sep 2015 01:14:45 +0100 Subject: [PATCH] Add SMI driver Signed-off-by: Luke Wren MISC: bcm2835: smi: use clock manager and fix reload issues Use clock manager instead of self-made clockmanager. Also fix some error paths that showd up during development (especially missing release of dma resources on rmmod) Signed-off-by: Martin Sperl bcm2835_smi: re-add dereference to fix DMA transfers --- .../bindings/misc/brcm,bcm2835-smi-dev.txt | 17 + .../devicetree/bindings/misc/brcm,bcm2835-smi.txt | 48 ++ drivers/char/broadcom/Kconfig | 9 + drivers/char/broadcom/Makefile | 1 + drivers/char/broadcom/bcm2835_smi_dev.c | 402 +++++++++ drivers/misc/Kconfig | 8 + drivers/misc/Makefile | 1 + drivers/misc/bcm2835_smi.c | 955 +++++++++++++++++++++ include/linux/broadcom/bcm2835_smi.h | 391 +++++++++ 9 files changed, 1832 insertions(+) create mode 100644 Documentation/devicetree/bindings/misc/brcm,bcm2835-smi-dev.txt create mode 100644 Documentation/devicetree/bindings/misc/brcm,bcm2835-smi.txt create mode 100644 drivers/char/broadcom/bcm2835_smi_dev.c create mode 100644 drivers/misc/bcm2835_smi.c create mode 100644 include/linux/broadcom/bcm2835_smi.h diff --git a/Documentation/devicetree/bindings/misc/brcm,bcm2835-smi-dev.txt b/Documentation/devicetree/bindings/misc/brcm,bcm2835-smi-dev.txt new file mode 100644 index 0000000..68cc8eb --- /dev/null +++ b/Documentation/devicetree/bindings/misc/brcm,bcm2835-smi-dev.txt @@ -0,0 +1,17 @@ +* Broadcom BCM2835 SMI character device driver. + +SMI or secondary memory interface is a peripheral specific to certain Broadcom +SOCs, and is helpful for talking to things like parallel-interface displays +and NAND flashes (in fact, most things with a parallel register interface). + +This driver adds a character device which provides a user-space interface to +an instance of the SMI driver. + +Required properties: +- compatible: "brcm,bcm2835-smi-dev" +- smi_handle: a phandle to the smi node. + +Optional properties: +- None. + + diff --git a/Documentation/devicetree/bindings/misc/brcm,bcm2835-smi.txt b/Documentation/devicetree/bindings/misc/brcm,bcm2835-smi.txt new file mode 100644 index 0000000..b76dc69 --- /dev/null +++ b/Documentation/devicetree/bindings/misc/brcm,bcm2835-smi.txt @@ -0,0 +1,48 @@ +* Broadcom BCM2835 SMI driver. + +SMI or secondary memory interface is a peripheral specific to certain Broadcom +SOCs, and is helpful for talking to things like parallel-interface displays +and NAND flashes (in fact, most things with a parallel register interface). + +Required properties: +- compatible: "brcm,bcm2835-smi" +- reg: Should contain location and length of SMI registers and SMI clkman regs +- interrupts: *the* SMI interrupt. +- pinctrl-names: should be "default". +- pinctrl-0: the phandle of the gpio pin node. +- brcm,smi-clock-source: the clock source for clkman +- brcm,smi-clock-divisor: the integer clock divisor for clkman +- dmas: the dma controller phandle and the DREQ number (4 on a 2835) +- dma-names: the name used by the driver to request its channel. + Should be "rx-tx". + +Optional properties: +- None. + +Examples: + +8 data pin configuration: + +smi: smi@7e600000 { + compatible = "brcm,bcm2835-smi"; + reg = <0x7e600000 0x44>, <0x7e1010b0 0x8>; + interrupts = <2 16>; + pinctrl-names = "default"; + pinctrl-0 = <&smi_pins>; + brcm,smi-clock-source = <6>; + brcm,smi-clock-divisor = <4>; + dmas = <&dma 4>; + dma-names = "rx-tx"; + + status = "okay"; +}; + +smi_pins: smi_pins { + brcm,pins = <2 3 4 5 6 7 8 9 10 11 12 13 14 15>; + /* Alt 1: SMI */ + brcm,function = <5 5 5 5 5 5 5 5 5 5 5 5 5 5>; + /* /CS, /WE and /OE are pulled high, as they are + generally active low signals */ + brcm,pull = <2 2 2 2 2 2 0 0 0 0 0 0 0 0>; +}; + diff --git a/drivers/char/broadcom/Kconfig b/drivers/char/broadcom/Kconfig index 13d4fce..48d29e5 100644 --- a/drivers/char/broadcom/Kconfig +++ b/drivers/char/broadcom/Kconfig @@ -24,3 +24,12 @@ config BCM2835_DEVGPIOMEM Provides users with root-free access to the GPIO registers on the 2835. Calling mmap(/dev/gpiomem) will map the GPIO register page to the user's pointer. + +config BCM2835_SMI_DEV + tristate "Character device driver for BCM2835 Secondary Memory Interface" + depends on BCM2835_SMI + default m + help + This driver provides a character device interface (ioctl + read/write) to + Broadcom's Secondary Memory interface. The low-level functionality is provided + by the SMI driver itself. diff --git a/drivers/char/broadcom/Makefile b/drivers/char/broadcom/Makefile index c8747a4..a5d0f33 100644 --- a/drivers/char/broadcom/Makefile +++ b/drivers/char/broadcom/Makefile @@ -1,2 +1,3 @@ obj-$(CONFIG_BCM2708_VCMEM) += vc_mem.o obj-$(CONFIG_BCM2835_DEVGPIOMEM)+= bcm2835-gpiomem.o +obj-$(CONFIG_BCM2835_SMI_DEV) += bcm2835_smi_dev.o diff --git a/drivers/char/broadcom/bcm2835_smi_dev.c b/drivers/char/broadcom/bcm2835_smi_dev.c new file mode 100644 index 0000000..9db8f1e --- /dev/null +++ b/drivers/char/broadcom/bcm2835_smi_dev.c @@ -0,0 +1,402 @@ +/** + * Character device driver for Broadcom Secondary Memory Interface + * + * Written by Luke Wren + * Copyright (c) 2015, Raspberry Pi (Trading) Ltd. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions, and the following disclaimer, + * without modification. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The names of the above-listed copyright holders may not be used + * to endorse or promote products derived from this software without + * specific prior written permission. + * + * ALTERNATIVELY, this software may be distributed under the terms of the + * GNU General Public License ("GPL") version 2, as published by the Free + * Software Foundation. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS + * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#define DEVICE_NAME "bcm2835-smi-dev" +#define DRIVER_NAME "smi-dev-bcm2835" +#define DEVICE_MINOR 0 + +static struct cdev bcm2835_smi_cdev; +static dev_t bcm2835_smi_devid; +static struct class *bcm2835_smi_class; +static struct device *bcm2835_smi_dev; + +struct bcm2835_smi_dev_instance { + struct device *dev; +}; + +static struct bcm2835_smi_instance *smi_inst; +static struct bcm2835_smi_dev_instance *inst; + +static const char *const ioctl_names[] = { + "READ_SETTINGS", + "WRITE_SETTINGS", + "ADDRESS" +}; + +/**************************************************************************** +* +* SMI chardev file ops +* +***************************************************************************/ +static long +bcm2835_smi_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + long ret = 0; + + dev_info(inst->dev, "serving ioctl..."); + + switch (cmd) { + case BCM2835_SMI_IOC_GET_SETTINGS:{ + struct smi_settings *settings; + + dev_info(inst->dev, "Reading SMI settings to user."); + settings = bcm2835_smi_get_settings_from_regs(smi_inst); + if (copy_to_user((void *)arg, settings, + sizeof(struct smi_settings))) + dev_err(inst->dev, "settings copy failed."); + break; + } + case BCM2835_SMI_IOC_WRITE_SETTINGS:{ + struct smi_settings *settings; + + dev_info(inst->dev, "Setting user's SMI settings."); + settings = bcm2835_smi_get_settings_from_regs(smi_inst); + if (copy_from_user(settings, (void *)arg, + sizeof(struct smi_settings))) + dev_err(inst->dev, "settings copy failed."); + else + bcm2835_smi_set_regs_from_settings(smi_inst); + break; + } + case BCM2835_SMI_IOC_ADDRESS: + dev_info(inst->dev, "SMI address set: 0x%02x", (int)arg); + bcm2835_smi_set_address(smi_inst, arg); + break; + default: + dev_err(inst->dev, "invalid ioctl cmd: %d", cmd); + ret = -ENOTTY; + break; + } + + return ret; +} + +static int bcm2835_smi_open(struct inode *inode, struct file *file) +{ + int dev = iminor(inode); + + dev_dbg(inst->dev, "SMI device opened."); + + if (dev != DEVICE_MINOR) { + dev_err(inst->dev, + "bcm2835_smi_release: Unknown minor device: %d", + dev); + return -ENXIO; + } + + return 0; +} + +static int bcm2835_smi_release(struct inode *inode, struct file *file) +{ + int dev = iminor(inode); + + if (dev != DEVICE_MINOR) { + dev_err(inst->dev, + "bcm2835_smi_release: Unknown minor device %d", dev); + return -ENXIO; + } + + return 0; +} + +static ssize_t dma_bounce_user( + enum dma_transfer_direction dma_dir, + char __user *user_ptr, + size_t count, + struct bcm2835_smi_bounce_info *bounce) +{ + int chunk_size; + int chunk_no = 0; + int count_left = count; + + while (count_left) { + int rv; + void *buf; + + /* Wait for current chunk to complete: */ + if (down_timeout(&bounce->callback_sem, + msecs_to_jiffies(1000))) { + dev_err(inst->dev, "DMA bounce timed out"); + count -= (count_left); + break; + } + + if (bounce->callback_sem.count >= DMA_BOUNCE_BUFFER_COUNT - 1) + dev_err(inst->dev, "WARNING: Ring buffer overflow"); + chunk_size = count_left > DMA_BOUNCE_BUFFER_SIZE ? + DMA_BOUNCE_BUFFER_SIZE : count_left; + buf = bounce->buffer[chunk_no % DMA_BOUNCE_BUFFER_COUNT]; + if (dma_dir == DMA_DEV_TO_MEM) + rv = copy_to_user(user_ptr, buf, chunk_size); + else + rv = copy_from_user(buf, user_ptr, chunk_size); + if (rv) + dev_err(inst->dev, "copy_*_user() failed!: %d", rv); + user_ptr += chunk_size; + count_left -= chunk_size; + chunk_no++; + } + return count; +} + +static ssize_t +bcm2835_read_file(struct file *f, char __user *user_ptr, + size_t count, loff_t *offs) +{ + int odd_bytes; + + dev_dbg(inst->dev, "User reading %zu bytes from SMI.", count); + /* We don't want to DMA a number of bytes % 4 != 0 (32 bit FIFO) */ + if (count > DMA_THRESHOLD_BYTES) + odd_bytes = count & 0x3; + else + odd_bytes = count; + count -= odd_bytes; + if (count) { + struct bcm2835_smi_bounce_info *bounce; + + count = bcm2835_smi_user_dma(smi_inst, + DMA_DEV_TO_MEM, user_ptr, count, + &bounce); + if (count) + count = dma_bounce_user(DMA_DEV_TO_MEM, user_ptr, + count, bounce); + } + if (odd_bytes) { + /* Read from FIFO directly if not using DMA */ + uint8_t buf[DMA_THRESHOLD_BYTES]; + + bcm2835_smi_read_buf(smi_inst, buf, odd_bytes); + if (copy_to_user(user_ptr, buf, odd_bytes)) + dev_err(inst->dev, "copy_to_user() failed."); + count += odd_bytes; + + } + return count; +} + +static ssize_t +bcm2835_write_file(struct file *f, const char __user *user_ptr, + size_t count, loff_t *offs) +{ + int odd_bytes; + + dev_dbg(inst->dev, "User writing %zu bytes to SMI.", count); + if (count > DMA_THRESHOLD_BYTES) + odd_bytes = count & 0x3; + else + odd_bytes = count; + count -= odd_bytes; + if (count) { + struct bcm2835_smi_bounce_info *bounce; + + count = bcm2835_smi_user_dma(smi_inst, + DMA_MEM_TO_DEV, (char __user *)user_ptr, count, + &bounce); + if (count) + count = dma_bounce_user(DMA_MEM_TO_DEV, + (char __user *)user_ptr, + count, bounce); + } + if (odd_bytes) { + uint8_t buf[DMA_THRESHOLD_BYTES]; + + if (copy_from_user(buf, user_ptr, odd_bytes)) + dev_err(inst->dev, "copy_from_user() failed."); + else + bcm2835_smi_write_buf(smi_inst, buf, odd_bytes); + count += odd_bytes; + } + return count; +} + +static const struct file_operations +bcm2835_smi_fops = { + .owner = THIS_MODULE, + .unlocked_ioctl = bcm2835_smi_ioctl, + .open = bcm2835_smi_open, + .release = bcm2835_smi_release, + .read = bcm2835_read_file, + .write = bcm2835_write_file, +}; + + +/**************************************************************************** +* +* bcm2835_smi_probe - called when the driver is loaded. +* +***************************************************************************/ + +static int bcm2835_smi_dev_probe(struct platform_device *pdev) +{ + int err; + void *ptr_err; + struct device *dev = &pdev->dev; + struct device_node *node = dev->of_node, *smi_node; + + if (!node) { + dev_err(dev, "No device tree node supplied!"); + return -EINVAL; + } + + smi_node = of_parse_phandle(node, "smi_handle", 0); + + if (!smi_node) { + dev_err(dev, "No such property: smi_handle"); + return -ENXIO; + } + + smi_inst = bcm2835_smi_get(smi_node); + + if (!smi_inst) + return -EPROBE_DEFER; + + /* Allocate buffers and instance data */ + + inst = devm_kzalloc(dev, sizeof(*inst), GFP_KERNEL); + + if (!inst) + return -ENOMEM; + + inst->dev = dev; + + /* Create character device entries */ + + err = alloc_chrdev_region(&bcm2835_smi_devid, + DEVICE_MINOR, 1, DEVICE_NAME); + if (err != 0) { + dev_err(inst->dev, "unable to allocate device number"); + return -ENOMEM; + } + cdev_init(&bcm2835_smi_cdev, &bcm2835_smi_fops); + bcm2835_smi_cdev.owner = THIS_MODULE; + err = cdev_add(&bcm2835_smi_cdev, bcm2835_smi_devid, 1); + if (err != 0) { + dev_err(inst->dev, "unable to register device"); + err = -ENOMEM; + goto failed_cdev_add; + } + + /* Create sysfs entries */ + + bcm2835_smi_class = class_create(THIS_MODULE, DEVICE_NAME); + ptr_err = bcm2835_smi_class; + if (IS_ERR(ptr_err)) + goto failed_class_create; + + bcm2835_smi_dev = device_create(bcm2835_smi_class, NULL, + bcm2835_smi_devid, NULL, + "smi"); + ptr_err = bcm2835_smi_dev; + if (IS_ERR(ptr_err)) + goto failed_device_create; + + dev_info(inst->dev, "initialised"); + + return 0; + +failed_device_create: + class_destroy(bcm2835_smi_class); +failed_class_create: + cdev_del(&bcm2835_smi_cdev); + err = PTR_ERR(ptr_err); +failed_cdev_add: + unregister_chrdev_region(bcm2835_smi_devid, 1); + dev_err(dev, "could not load bcm2835_smi_dev"); + return err; +} + +/**************************************************************************** +* +* bcm2835_smi_remove - called when the driver is unloaded. +* +***************************************************************************/ + +static int bcm2835_smi_dev_remove(struct platform_device *pdev) +{ + device_destroy(bcm2835_smi_class, bcm2835_smi_devid); + class_destroy(bcm2835_smi_class); + cdev_del(&bcm2835_smi_cdev); + unregister_chrdev_region(bcm2835_smi_devid, 1); + + dev_info(inst->dev, "SMI character dev removed - OK"); + return 0; +} + +/**************************************************************************** +* +* Register the driver with device tree +* +***************************************************************************/ + +static const struct of_device_id bcm2835_smi_dev_of_match[] = { + {.compatible = "brcm,bcm2835-smi-dev",}, + { /* sentinel */ }, +}; + +MODULE_DEVICE_TABLE(of, bcm2835_smi_dev_of_match); + +static struct platform_driver bcm2835_smi_dev_driver = { + .probe = bcm2835_smi_dev_probe, + .remove = bcm2835_smi_dev_remove, + .driver = { + .name = DRIVER_NAME, + .owner = THIS_MODULE, + .of_match_table = bcm2835_smi_dev_of_match, + }, +}; + +module_platform_driver(bcm2835_smi_dev_driver); + +MODULE_ALIAS("platform:smi-dev-bcm2835"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION( + "Character device driver for BCM2835's secondary memory interface"); +MODULE_AUTHOR("Luke Wren "); diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 0f5a49f..6063314 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -9,6 +9,14 @@ config SENSORS_LIS3LV02D tristate depends on INPUT +config BCM2835_SMI + tristate "Broadcom 283x Secondary Memory Interface driver" + depends on ARCH_BCM2835 + default m + help + Driver for enabling and using Broadcom's Secondary/Slow Memory Interface. + Appears as /dev/bcm2835_smi. For ioctl interface see drivers/misc/bcm2835_smi.h + config AD525X_DPOT tristate "Analog Devices Digital Potentiometers" depends on (I2C || SPI) && SYSFS diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index a086197..e0188c3 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -9,6 +9,7 @@ obj-$(CONFIG_AD525X_DPOT) += ad525x_dpot.o obj-$(CONFIG_AD525X_DPOT_I2C) += ad525x_dpot-i2c.o obj-$(CONFIG_AD525X_DPOT_SPI) += ad525x_dpot-spi.o obj-$(CONFIG_ATMEL_SSC) += atmel-ssc.o +obj-$(CONFIG_BCM2835_SMI) += bcm2835_smi.o obj-$(CONFIG_DUMMY_IRQ) += dummy-irq.o obj-$(CONFIG_ICS932S401) += ics932s401.o obj-$(CONFIG_LKDTM) += lkdtm/ diff --git a/drivers/misc/bcm2835_smi.c b/drivers/misc/bcm2835_smi.c new file mode 100644 index 0000000..f1a7f6a --- /dev/null +++ b/drivers/misc/bcm2835_smi.c @@ -0,0 +1,955 @@ +/** + * Broadcom Secondary Memory Interface driver + * + * Written by Luke Wren + * Copyright (c) 2015, Raspberry Pi (Trading) Ltd. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions, and the following disclaimer, + * without modification. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The names of the above-listed copyright holders may not be used + * to endorse or promote products derived from this software without + * specific prior written permission. + * + * ALTERNATIVELY, this software may be distributed under the terms of the + * GNU General Public License ("GPL") version 2, as published by the Free + * Software Foundation. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS + * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define BCM2835_SMI_IMPLEMENTATION +#include + +#define DRIVER_NAME "smi-bcm2835" + +#define N_PAGES_FROM_BYTES(n) ((n + PAGE_SIZE-1) / PAGE_SIZE) + +#define DMA_WRITE_TO_MEM true +#define DMA_READ_FROM_MEM false + +struct bcm2835_smi_instance { + struct device *dev; + struct smi_settings settings; + __iomem void *smi_regs_ptr; + dma_addr_t smi_regs_busaddr; + + struct dma_chan *dma_chan; + struct dma_slave_config dma_config; + + struct bcm2835_smi_bounce_info bounce; + + struct scatterlist buffer_sgl; + + struct clk *clk; + + /* Sometimes we are called into in an atomic context (e.g. by + JFFS2 + MTD) so we can't use a mutex */ + spinlock_t transaction_lock; +}; + +/**************************************************************************** +* +* SMI peripheral setup +* +***************************************************************************/ + +static inline void write_smi_reg(struct bcm2835_smi_instance *inst, + u32 val, unsigned reg) +{ + writel(val, inst->smi_regs_ptr + reg); +} + +static inline u32 read_smi_reg(struct bcm2835_smi_instance *inst, unsigned reg) +{ + return readl(inst->smi_regs_ptr + reg); +} + +/* Token-paste macro for e.g SMIDSR_RSTROBE -> value of SMIDSR_RSTROBE_MASK */ +#define _CONCAT(x, y) x##y +#define CONCAT(x, y) _CONCAT(x, y) + +#define SET_BIT_FIELD(dest, field, bits) ((dest) = \ + ((dest) & ~CONCAT(field, _MASK)) | (((bits) << CONCAT(field, _OFFS))& \ + CONCAT(field, _MASK))) +#define GET_BIT_FIELD(src, field) (((src) & \ + CONCAT(field, _MASK)) >> CONCAT(field, _OFFS)) + +static void smi_dump_context_labelled(struct bcm2835_smi_instance *inst, + const char *label) +{ + dev_err(inst->dev, "SMI context dump: %s", label); + dev_err(inst->dev, "SMICS: 0x%08x", read_smi_reg(inst, SMICS)); + dev_err(inst->dev, "SMIL: 0x%08x", read_smi_reg(inst, SMIL)); + dev_err(inst->dev, "SMIDSR: 0x%08x", read_smi_reg(inst, SMIDSR0)); + dev_err(inst->dev, "SMIDSW: 0x%08x", read_smi_reg(inst, SMIDSW0)); + dev_err(inst->dev, "SMIDC: 0x%08x", read_smi_reg(inst, SMIDC)); + dev_err(inst->dev, "SMIFD: 0x%08x", read_smi_reg(inst, SMIFD)); + dev_err(inst->dev, " "); +} + +static inline void smi_dump_context(struct bcm2835_smi_instance *inst) +{ + smi_dump_context_labelled(inst, ""); +} + +static void smi_get_default_settings(struct bcm2835_smi_instance *inst) +{ + struct smi_settings *settings = &inst->settings; + + settings->data_width = SMI_WIDTH_16BIT; + settings->pack_data = true; + + settings->read_setup_time = 1; + settings->read_hold_time = 1; + settings->read_pace_time = 1; + settings->read_strobe_time = 3; + + settings->write_setup_time = settings->read_setup_time; + settings->write_hold_time = settings->read_hold_time; + settings->write_pace_time = settings->read_pace_time; + settings->write_strobe_time = settings->read_strobe_time; + + settings->dma_enable = true; + settings->dma_passthrough_enable = false; + settings->dma_read_thresh = 0x01; + settings->dma_write_thresh = 0x3f; + settings->dma_panic_read_thresh = 0x20; + settings->dma_panic_write_thresh = 0x20; +} + +void bcm2835_smi_set_regs_from_settings(struct bcm2835_smi_instance *inst) +{ + struct smi_settings *settings = &inst->settings; + int smidsr_temp = 0, smidsw_temp = 0, smics_temp, + smidcs_temp, smidc_temp = 0; + + spin_lock(&inst->transaction_lock); + + /* temporarily disable the peripheral: */ + smics_temp = read_smi_reg(inst, SMICS); + write_smi_reg(inst, 0, SMICS); + smidcs_temp = read_smi_reg(inst, SMIDCS); + write_smi_reg(inst, 0, SMIDCS); + + if (settings->pack_data) + smics_temp |= SMICS_PXLDAT; + else + smics_temp &= ~SMICS_PXLDAT; + + SET_BIT_FIELD(smidsr_temp, SMIDSR_RWIDTH, settings->data_width); + SET_BIT_FIELD(smidsr_temp, SMIDSR_RSETUP, settings->read_setup_time); + SET_BIT_FIELD(smidsr_temp, SMIDSR_RHOLD, settings->read_hold_time); + SET_BIT_FIELD(smidsr_temp, SMIDSR_RPACE, settings->read_pace_time); + SET_BIT_FIELD(smidsr_temp, SMIDSR_RSTROBE, settings->read_strobe_time); + write_smi_reg(inst, smidsr_temp, SMIDSR0); + + SET_BIT_FIELD(smidsw_temp, SMIDSW_WWIDTH, settings->data_width); + if (settings->data_width == SMI_WIDTH_8BIT) + smidsw_temp |= SMIDSW_WSWAP; + else + smidsw_temp &= ~SMIDSW_WSWAP; + SET_BIT_FIELD(smidsw_temp, SMIDSW_WSETUP, settings->write_setup_time); + SET_BIT_FIELD(smidsw_temp, SMIDSW_WHOLD, settings->write_hold_time); + SET_BIT_FIELD(smidsw_temp, SMIDSW_WPACE, settings->write_pace_time); + SET_BIT_FIELD(smidsw_temp, SMIDSW_WSTROBE, + settings->write_strobe_time); + write_smi_reg(inst, smidsw_temp, SMIDSW0); + + SET_BIT_FIELD(smidc_temp, SMIDC_REQR, settings->dma_read_thresh); + SET_BIT_FIELD(smidc_temp, SMIDC_REQW, settings->dma_write_thresh); + SET_BIT_FIELD(smidc_temp, SMIDC_PANICR, + settings->dma_panic_read_thresh); + SET_BIT_FIELD(smidc_temp, SMIDC_PANICW, + settings->dma_panic_write_thresh); + if (settings->dma_passthrough_enable) { + smidc_temp |= SMIDC_DMAP; + smidsr_temp |= SMIDSR_RDREQ; + write_smi_reg(inst, smidsr_temp, SMIDSR0); + smidsw_temp |= SMIDSW_WDREQ; + write_smi_reg(inst, smidsw_temp, SMIDSW0); + } else + smidc_temp &= ~SMIDC_DMAP; + if (settings->dma_enable) + smidc_temp |= SMIDC_DMAEN; + else + smidc_temp &= ~SMIDC_DMAEN; + + write_smi_reg(inst, smidc_temp, SMIDC); + + /* re-enable (if was previously enabled) */ + write_smi_reg(inst, smics_temp, SMICS); + write_smi_reg(inst, smidcs_temp, SMIDCS); + + spin_unlock(&inst->transaction_lock); +} +EXPORT_SYMBOL(bcm2835_smi_set_regs_from_settings); + +struct smi_settings *bcm2835_smi_get_settings_from_regs + (struct bcm2835_smi_instance *inst) +{ + struct smi_settings *settings = &inst->settings; + int smidsr, smidsw, smidc; + + spin_lock(&inst->transaction_lock); + + smidsr = read_smi_reg(inst, SMIDSR0); + smidsw = read_smi_reg(inst, SMIDSW0); + smidc = read_smi_reg(inst, SMIDC); + + settings->pack_data = (read_smi_reg(inst, SMICS) & SMICS_PXLDAT) ? + true : false; + + settings->data_width = GET_BIT_FIELD(smidsr, SMIDSR_RWIDTH); + settings->read_setup_time = GET_BIT_FIELD(smidsr, SMIDSR_RSETUP); + settings->read_hold_time = GET_BIT_FIELD(smidsr, SMIDSR_RHOLD); + settings->read_pace_time = GET_BIT_FIELD(smidsr, SMIDSR_RPACE); + settings->read_strobe_time = GET_BIT_FIELD(smidsr, SMIDSR_RSTROBE); + + settings->write_setup_time = GET_BIT_FIELD(smidsw, SMIDSW_WSETUP); + settings->write_hold_time = GET_BIT_FIELD(smidsw, SMIDSW_WHOLD); + settings->write_pace_time = GET_BIT_FIELD(smidsw, SMIDSW_WPACE); + settings->write_strobe_time = GET_BIT_FIELD(smidsw, SMIDSW_WSTROBE); + + settings->dma_read_thresh = GET_BIT_FIELD(smidc, SMIDC_REQR); + settings->dma_write_thresh = GET_BIT_FIELD(smidc, SMIDC_REQW); + settings->dma_panic_read_thresh = GET_BIT_FIELD(smidc, SMIDC_PANICR); + settings->dma_panic_write_thresh = GET_BIT_FIELD(smidc, SMIDC_PANICW); + settings->dma_passthrough_enable = (smidc & SMIDC_DMAP) ? true : false; + settings->dma_enable = (smidc & SMIDC_DMAEN) ? true : false; + + spin_unlock(&inst->transaction_lock); + + return settings; +} +EXPORT_SYMBOL(bcm2835_smi_get_settings_from_regs); + +static inline void smi_set_address(struct bcm2835_smi_instance *inst, + unsigned int address) +{ + int smia_temp = 0, smida_temp = 0; + + SET_BIT_FIELD(smia_temp, SMIA_ADDR, address); + SET_BIT_FIELD(smida_temp, SMIDA_ADDR, address); + + /* Write to both address registers - user doesn't care whether we're + doing programmed or direct transfers. */ + write_smi_reg(inst, smia_temp, SMIA); + write_smi_reg(inst, smida_temp, SMIDA); +} + +static void smi_setup_regs(struct bcm2835_smi_instance *inst) +{ + + dev_dbg(inst->dev, "Initialising SMI registers..."); + /* Disable the peripheral if already enabled */ + write_smi_reg(inst, 0, SMICS); + write_smi_reg(inst, 0, SMIDCS); + + smi_get_default_settings(inst); + bcm2835_smi_set_regs_from_settings(inst); + smi_set_address(inst, 0); + + write_smi_reg(inst, read_smi_reg(inst, SMICS) | SMICS_ENABLE, SMICS); + write_smi_reg(inst, read_smi_reg(inst, SMIDCS) | SMIDCS_ENABLE, + SMIDCS); +} + +/**************************************************************************** +* +* Low-level SMI access functions +* Other modules should use the exported higher-level functions e.g. +* bcm2835_smi_write_buf() unless they have a good reason to use these +* +***************************************************************************/ + +static inline uint32_t smi_read_single_word(struct bcm2835_smi_instance *inst) +{ + int timeout = 0; + + write_smi_reg(inst, SMIDCS_ENABLE, SMIDCS); + write_smi_reg(inst, SMIDCS_ENABLE | SMIDCS_START, SMIDCS); + /* Make sure things happen in the right order...*/ + mb(); + while (!(read_smi_reg(inst, SMIDCS) & SMIDCS_DONE) && + ++timeout < 10000) + ; + if (timeout < 10000) + return read_smi_reg(inst, SMIDD); + + dev_err(inst->dev, + "SMI direct read timed out (is the clock set up correctly?)"); + return 0; +} + +static inline void smi_write_single_word(struct bcm2835_smi_instance *inst, + uint32_t data) +{ + int timeout = 0; + + write_smi_reg(inst, SMIDCS_ENABLE | SMIDCS_WRITE, SMIDCS); + write_smi_reg(inst, data, SMIDD); + write_smi_reg(inst, SMIDCS_ENABLE | SMIDCS_WRITE | SMIDCS_START, + SMIDCS); + + while (!(read_smi_reg(inst, SMIDCS) & SMIDCS_DONE) && + ++timeout < 10000) + ; + if (timeout >= 10000) + dev_err(inst->dev, + "SMI direct write timed out (is the clock set up correctly?)"); +} + +/* Initiates a programmed read into the read FIFO. It is up to the caller to + * read data from the FIFO - either via paced DMA transfer, + * or polling SMICS_RXD to check whether data is available. + * SMICS_ACTIVE will go low upon completion. */ +static void smi_init_programmed_read(struct bcm2835_smi_instance *inst, + int num_transfers) +{ + int smics_temp; + + /* Disable the peripheral: */ + smics_temp = read_smi_reg(inst, SMICS) & ~(SMICS_ENABLE | SMICS_WRITE); + write_smi_reg(inst, smics_temp, SMICS); + while (read_smi_reg(inst, SMICS) & SMICS_ENABLE) + ; + + /* Program the transfer count: */ + write_smi_reg(inst, num_transfers, SMIL); + + /* re-enable and start: */ + smics_temp |= SMICS_ENABLE; + write_smi_reg(inst, smics_temp, SMICS); + smics_temp |= SMICS_CLEAR; + /* Just to be certain: */ + mb(); + while (read_smi_reg(inst, SMICS) & SMICS_ACTIVE) + ; + write_smi_reg(inst, smics_temp, SMICS); + smics_temp |= SMICS_START; + write_smi_reg(inst, smics_temp, SMICS); +} + +/* Initiates a programmed write sequence, using data from the write FIFO. + * It is up to the caller to initiate a DMA transfer before calling, + * or use another method to keep the write FIFO topped up. + * SMICS_ACTIVE will go low upon completion. + */ +static void smi_init_programmed_write(struct bcm2835_smi_instance *inst, + int num_transfers) +{ + int smics_temp; + + /* Disable the peripheral: */ + smics_temp = read_smi_reg(inst, SMICS) & ~SMICS_ENABLE; + write_smi_reg(inst, smics_temp, SMICS); + while (read_smi_reg(inst, SMICS) & SMICS_ENABLE) + ; + + /* Program the transfer count: */ + write_smi_reg(inst, num_transfers, SMIL); + + /* setup, re-enable and start: */ + smics_temp |= SMICS_WRITE | SMICS_ENABLE; + write_smi_reg(inst, smics_temp, SMICS); + smics_temp |= SMICS_START; + write_smi_reg(inst, smics_temp, SMICS); +} + +/* Initiate a read and then poll FIFO for data, reading out as it appears. */ +static void smi_read_fifo(struct bcm2835_smi_instance *inst, + uint32_t *dest, int n_bytes) +{ + if (read_smi_reg(inst, SMICS) & SMICS_RXD) { + smi_dump_context_labelled(inst, + "WARNING: read FIFO not empty at start of read call."); + while (read_smi_reg(inst, SMICS)) + ; + } + + /* Dispatch the read: */ + if (inst->settings.data_width == SMI_WIDTH_8BIT) + smi_init_programmed_read(inst, n_bytes); + else if (inst->settings.data_width == SMI_WIDTH_16BIT) + smi_init_programmed_read(inst, n_bytes / 2); + else { + dev_err(inst->dev, "Unsupported data width for read."); + return; + } + + /* Poll FIFO to keep it empty */ + while (!(read_smi_reg(inst, SMICS) & SMICS_DONE)) + if (read_smi_reg(inst, SMICS) & SMICS_RXD) + *dest++ = read_smi_reg(inst, SMID); + + /* Ensure that the FIFO is emptied */ + if (read_smi_reg(inst, SMICS) & SMICS_RXD) { + int fifo_count; + + fifo_count = GET_BIT_FIELD(read_smi_reg(inst, SMIFD), + SMIFD_FCNT); + while (fifo_count--) + *dest++ = read_smi_reg(inst, SMID); + } + + if (!(read_smi_reg(inst, SMICS) & SMICS_DONE)) + smi_dump_context_labelled(inst, + "WARNING: transaction finished but done bit not set."); + + if (read_smi_reg(inst, SMICS) & SMICS_RXD) + smi_dump_context_labelled(inst, + "WARNING: read FIFO not empty at end of read call."); + +} + +/* Initiate a write, and then keep the FIFO topped up. */ +static void smi_write_fifo(struct bcm2835_smi_instance *inst, + uint32_t *src, int n_bytes) +{ + int i, timeout = 0; + + /* Empty FIFOs if not already so */ + if (!(read_smi_reg(inst, SMICS) & SMICS_TXE)) { + smi_dump_context_labelled(inst, + "WARNING: write fifo not empty at start of write call."); + write_smi_reg(inst, read_smi_reg(inst, SMICS) | SMICS_CLEAR, + SMICS); + } + + /* Initiate the transfer */ + if (inst->settings.data_width == SMI_WIDTH_8BIT) + smi_init_programmed_write(inst, n_bytes); + else if (inst->settings.data_width == SMI_WIDTH_16BIT) + smi_init_programmed_write(inst, n_bytes / 2); + else { + dev_err(inst->dev, "Unsupported data width for write."); + return; + } + /* Fill the FIFO: */ + for (i = 0; i < (n_bytes - 1) / 4 + 1; ++i) { + while (!(read_smi_reg(inst, SMICS) & SMICS_TXD)) + ; + write_smi_reg(inst, *src++, SMID); + } + /* Busy wait... */ + while (!(read_smi_reg(inst, SMICS) & SMICS_DONE) && ++timeout < + 1000000) + ; + if (timeout >= 1000000) + smi_dump_context_labelled(inst, + "Timed out on write operation!"); + if (!(read_smi_reg(inst, SMICS) & SMICS_TXE)) + smi_dump_context_labelled(inst, + "WARNING: FIFO not empty at end of write operation."); +} + +/**************************************************************************** +* +* SMI DMA operations +* +***************************************************************************/ + +/* Disable SMI and put it into the correct direction before doing DMA setup. + Stops spurious DREQs during setup. Peripheral is re-enabled by init_*() */ +static void smi_disable(struct bcm2835_smi_instance *inst, + enum dma_transfer_direction direction) +{ + int smics_temp = read_smi_reg(inst, SMICS) & ~SMICS_ENABLE; + + if (direction == DMA_DEV_TO_MEM) + smics_temp &= ~SMICS_WRITE; + else + smics_temp |= SMICS_WRITE; + write_smi_reg(inst, smics_temp, SMICS); + while (read_smi_reg(inst, SMICS) & SMICS_ACTIVE) + ; +} + +static struct scatterlist *smi_scatterlist_from_buffer( + struct bcm2835_smi_instance *inst, + dma_addr_t buf, + size_t len, + struct scatterlist *sg) +{ + sg_init_table(sg, 1); + sg_dma_address(sg) = buf; + sg_dma_len(sg) = len; + return sg; +} + +static void smi_dma_callback_user_copy(void *param) +{ + /* Notify the bottom half that a chunk is ready for user copy */ + struct bcm2835_smi_instance *inst = + (struct bcm2835_smi_instance *)param; + + up(&inst->bounce.callback_sem); +} + +/* Creates a descriptor, assigns the given callback, and submits the + descriptor to dmaengine. Does not block - can queue up multiple + descriptors and then wait for them all to complete. + sg_len is the number of control blocks, NOT the number of bytes. + dir can be DMA_MEM_TO_DEV or DMA_DEV_TO_MEM. + callback can be NULL - in this case it is not called. */ +static inline struct dma_async_tx_descriptor *smi_dma_submit_sgl( + struct bcm2835_smi_instance *inst, + struct scatterlist *sgl, + size_t sg_len, + enum dma_transfer_direction dir, + dma_async_tx_callback callback) +{ + struct dma_async_tx_descriptor *desc; + + desc = dmaengine_prep_slave_sg(inst->dma_chan, + sgl, + sg_len, + dir, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK | + DMA_PREP_FENCE); + if (!desc) { + dev_err(inst->dev, "read_sgl: dma slave preparation failed!"); + write_smi_reg(inst, read_smi_reg(inst, SMICS) & ~SMICS_ACTIVE, + SMICS); + while (read_smi_reg(inst, SMICS) & SMICS_ACTIVE) + cpu_relax(); + write_smi_reg(inst, read_smi_reg(inst, SMICS) | SMICS_ACTIVE, + SMICS); + return NULL; + } + desc->callback = callback; + desc->callback_param = inst; + if (dmaengine_submit(desc) < 0) + return NULL; + return desc; +} + +/* NB this function blocks until the transfer is complete */ +static void +smi_dma_read_sgl(struct bcm2835_smi_instance *inst, + struct scatterlist *sgl, size_t sg_len, size_t n_bytes) +{ + struct dma_async_tx_descriptor *desc; + + /* Disable SMI and set to read before dispatching DMA - if SMI is in + * write mode and TX fifo is empty, it will generate a DREQ which may + * cause the read DMA to complete before the SMI read command is even + * dispatched! We want to dispatch DMA before SMI read so that reading + * is gapless, for logic analyser. + */ + + smi_disable(inst, DMA_DEV_TO_MEM); + + desc = smi_dma_submit_sgl(inst, sgl, sg_len, DMA_DEV_TO_MEM, NULL); + dma_async_issue_pending(inst->dma_chan); + + if (inst->settings.data_width == SMI_WIDTH_8BIT) + smi_init_programmed_read(inst, n_bytes); + else + smi_init_programmed_read(inst, n_bytes / 2); + + if (dma_wait_for_async_tx(desc) == DMA_ERROR) + smi_dump_context_labelled(inst, "DMA timeout!"); +} + +static void +smi_dma_write_sgl(struct bcm2835_smi_instance *inst, + struct scatterlist *sgl, size_t sg_len, size_t n_bytes) +{ + struct dma_async_tx_descriptor *desc; + + if (inst->settings.data_width == SMI_WIDTH_8BIT) + smi_init_programmed_write(inst, n_bytes); + else + smi_init_programmed_write(inst, n_bytes / 2); + + desc = smi_dma_submit_sgl(inst, sgl, sg_len, DMA_MEM_TO_DEV, NULL); + dma_async_issue_pending(inst->dma_chan); + + if (dma_wait_for_async_tx(desc) == DMA_ERROR) + smi_dump_context_labelled(inst, "DMA timeout!"); + else + /* Wait for SMI to finish our writes */ + while (!(read_smi_reg(inst, SMICS) & SMICS_DONE)) + cpu_relax(); +} + +ssize_t bcm2835_smi_user_dma( + struct bcm2835_smi_instance *inst, + enum dma_transfer_direction dma_dir, + char __user *user_ptr, size_t count, + struct bcm2835_smi_bounce_info **bounce) +{ + int chunk_no = 0, chunk_size, count_left = count; + struct scatterlist *sgl; + void (*init_trans_func)(struct bcm2835_smi_instance *, int); + + spin_lock(&inst->transaction_lock); + + if (dma_dir == DMA_DEV_TO_MEM) + init_trans_func = smi_init_programmed_read; + else + init_trans_func = smi_init_programmed_write; + + smi_disable(inst, dma_dir); + + sema_init(&inst->bounce.callback_sem, 0); + if (bounce) + *bounce = &inst->bounce; + while (count_left) { + chunk_size = count_left > DMA_BOUNCE_BUFFER_SIZE ? + DMA_BOUNCE_BUFFER_SIZE : count_left; + if (chunk_size == DMA_BOUNCE_BUFFER_SIZE) { + sgl = + &inst->bounce.sgl[chunk_no % DMA_BOUNCE_BUFFER_COUNT]; + } else { + sgl = smi_scatterlist_from_buffer( + inst, + inst->bounce.phys[ + chunk_no % DMA_BOUNCE_BUFFER_COUNT], + chunk_size, + &inst->buffer_sgl); + } + + if (!smi_dma_submit_sgl(inst, sgl, 1, dma_dir, + smi_dma_callback_user_copy + )) { + dev_err(inst->dev, "sgl submit failed"); + count = 0; + goto out; + } + count_left -= chunk_size; + chunk_no++; + } + dma_async_issue_pending(inst->dma_chan); + + if (inst->settings.data_width == SMI_WIDTH_8BIT) + init_trans_func(inst, count); + else if (inst->settings.data_width == SMI_WIDTH_16BIT) + init_trans_func(inst, count / 2); +out: + spin_unlock(&inst->transaction_lock); + return count; +} +EXPORT_SYMBOL(bcm2835_smi_user_dma); + + +/**************************************************************************** +* +* High level buffer transfer functions - for use by other drivers +* +***************************************************************************/ + +/* Buffer must be physically contiguous - i.e. kmalloc, not vmalloc! */ +void bcm2835_smi_write_buf( + struct bcm2835_smi_instance *inst, + const void *buf, size_t n_bytes) +{ + int odd_bytes = n_bytes & 0x3; + + n_bytes -= odd_bytes; + + spin_lock(&inst->transaction_lock); + + if (n_bytes > DMA_THRESHOLD_BYTES) { + dma_addr_t phy_addr = dma_map_single( + inst->dev, + (void *)buf, + n_bytes, + DMA_MEM_TO_DEV); + struct scatterlist *sgl = + smi_scatterlist_from_buffer(inst, phy_addr, n_bytes, + &inst->buffer_sgl); + + if (!sgl) { + smi_dump_context_labelled(inst, + "Error: could not create scatterlist for write!"); + goto out; + } + smi_dma_write_sgl(inst, sgl, 1, n_bytes); + + dma_unmap_single + (inst->dev, phy_addr, n_bytes, DMA_MEM_TO_DEV); + } else if (n_bytes) { + smi_write_fifo(inst, (uint32_t *) buf, n_bytes); + } + buf += n_bytes; + + if (inst->settings.data_width == SMI_WIDTH_8BIT) { + while (odd_bytes--) + smi_write_single_word(inst, *(uint8_t *) (buf++)); + } else { + while (odd_bytes >= 2) { + smi_write_single_word(inst, *(uint16_t *)buf); + buf += 2; + odd_bytes -= 2; + } + if (odd_bytes) { + /* Reading an odd number of bytes on a 16 bit bus is + a user bug. It's kinder to fail early and tell them + than to e.g. transparently give them the bottom byte + of a 16 bit transfer. */ + dev_err(inst->dev, + "WARNING: odd number of bytes specified for wide transfer."); + dev_err(inst->dev, + "At least one byte dropped as a result."); + dump_stack(); + } + } +out: + spin_unlock(&inst->transaction_lock); +} +EXPORT_SYMBOL(bcm2835_smi_write_buf); + +void bcm2835_smi_read_buf(struct bcm2835_smi_instance *inst, + void *buf, size_t n_bytes) +{ + + /* SMI is inherently 32-bit, which causes surprising amounts of mess + for bytes % 4 != 0. Easiest to avoid this mess altogether + by handling remainder separately. */ + int odd_bytes = n_bytes & 0x3; + + spin_lock(&inst->transaction_lock); + n_bytes -= odd_bytes; + if (n_bytes > DMA_THRESHOLD_BYTES) { + dma_addr_t phy_addr = dma_map_single(inst->dev, + buf, n_bytes, + DMA_DEV_TO_MEM); + struct scatterlist *sgl = smi_scatterlist_from_buffer( + inst, phy_addr, n_bytes, + &inst->buffer_sgl); + if (!sgl) { + smi_dump_context_labelled(inst, + "Error: could not create scatterlist for read!"); + goto out; + } + smi_dma_read_sgl(inst, sgl, 1, n_bytes); + dma_unmap_single(inst->dev, phy_addr, n_bytes, DMA_DEV_TO_MEM); + } else if (n_bytes) { + smi_read_fifo(inst, (uint32_t *)buf, n_bytes); + } + buf += n_bytes; + + if (inst->settings.data_width == SMI_WIDTH_8BIT) { + while (odd_bytes--) + *((uint8_t *) (buf++)) = smi_read_single_word(inst); + } else { + while (odd_bytes >= 2) { + *(uint16_t *) buf = smi_read_single_word(inst); + buf += 2; + odd_bytes -= 2; + } + if (odd_bytes) { + dev_err(inst->dev, + "WARNING: odd number of bytes specified for wide transfer."); + dev_err(inst->dev, + "At least one byte dropped as a result."); + dump_stack(); + } + } +out: + spin_unlock(&inst->transaction_lock); +} +EXPORT_SYMBOL(bcm2835_smi_read_buf); + +void bcm2835_smi_set_address(struct bcm2835_smi_instance *inst, + unsigned int address) +{ + spin_lock(&inst->transaction_lock); + smi_set_address(inst, address); + spin_unlock(&inst->transaction_lock); +} +EXPORT_SYMBOL(bcm2835_smi_set_address); + +struct bcm2835_smi_instance *bcm2835_smi_get(struct device_node *node) +{ + struct platform_device *pdev; + + if (!node) + return NULL; + + pdev = of_find_device_by_node(node); + if (!pdev) + return NULL; + + return platform_get_drvdata(pdev); +} +EXPORT_SYMBOL(bcm2835_smi_get); + +/**************************************************************************** +* +* bcm2835_smi_probe - called when the driver is loaded. +* +***************************************************************************/ + +static int bcm2835_smi_dma_setup(struct bcm2835_smi_instance *inst) +{ + int i, rv = 0; + + inst->dma_chan = dma_request_slave_channel(inst->dev, "rx-tx"); + + inst->dma_config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; + inst->dma_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; + inst->dma_config.src_addr = inst->smi_regs_busaddr + SMID; + inst->dma_config.dst_addr = inst->dma_config.src_addr; + /* Direction unimportant - always overridden by prep_slave_sg */ + inst->dma_config.direction = DMA_DEV_TO_MEM; + dmaengine_slave_config(inst->dma_chan, &inst->dma_config); + /* Alloc and map bounce buffers */ + for (i = 0; i < DMA_BOUNCE_BUFFER_COUNT; ++i) { + inst->bounce.buffer[i] = + dmam_alloc_coherent(inst->dev, DMA_BOUNCE_BUFFER_SIZE, + &inst->bounce.phys[i], + GFP_KERNEL); + if (!inst->bounce.buffer[i]) { + dev_err(inst->dev, "Could not allocate buffer!"); + rv = -ENOMEM; + break; + } + smi_scatterlist_from_buffer( + inst, + inst->bounce.phys[i], + DMA_BOUNCE_BUFFER_SIZE, + &inst->bounce.sgl[i] + ); + } + + return rv; +} + +static int bcm2835_smi_probe(struct platform_device *pdev) +{ + int err; + struct device *dev = &pdev->dev; + struct device_node *node = dev->of_node; + struct resource *ioresource; + struct bcm2835_smi_instance *inst; + const __be32 *addr; + + /* We require device tree support */ + if (!node) + return -EINVAL; + /* Allocate buffers and instance data */ + inst = devm_kzalloc(dev, sizeof(struct bcm2835_smi_instance), + GFP_KERNEL); + if (!inst) + return -ENOMEM; + + inst->dev = dev; + spin_lock_init(&inst->transaction_lock); + + ioresource = platform_get_resource(pdev, IORESOURCE_MEM, 0); + inst->smi_regs_ptr = devm_ioremap_resource(dev, ioresource); + if (IS_ERR(inst->smi_regs_ptr)) { + err = PTR_ERR(inst->smi_regs_ptr); + goto err; + } + addr = of_get_address(node, 0, NULL, NULL); + inst->smi_regs_busaddr = be32_to_cpu(*addr); + + err = bcm2835_smi_dma_setup(inst); + if (err) + goto err; + + /* request clock */ + inst->clk = devm_clk_get(dev, NULL); + if (!inst->clk) + goto err; + clk_prepare_enable(inst->clk); + + /* Finally, do peripheral setup */ + smi_setup_regs(inst); + + platform_set_drvdata(pdev, inst); + + dev_info(inst->dev, "initialised"); + + return 0; +err: + kfree(inst); + return err; +} + +/**************************************************************************** +* +* bcm2835_smi_remove - called when the driver is unloaded. +* +***************************************************************************/ + +static int bcm2835_smi_remove(struct platform_device *pdev) +{ + struct bcm2835_smi_instance *inst = platform_get_drvdata(pdev); + struct device *dev = inst->dev; + + dmaengine_terminate_all(inst->dma_chan); + dma_release_channel(inst->dma_chan); + + clk_disable_unprepare(inst->clk); + + dev_info(dev, "SMI device removed - OK"); + return 0; +} + +/**************************************************************************** +* +* Register the driver with device tree +* +***************************************************************************/ + +static const struct of_device_id bcm2835_smi_of_match[] = { + {.compatible = "brcm,bcm2835-smi",}, + { /* sentinel */ }, +}; + +MODULE_DEVICE_TABLE(of, bcm2835_smi_of_match); + +static struct platform_driver bcm2835_smi_driver = { + .probe = bcm2835_smi_probe, + .remove = bcm2835_smi_remove, + .driver = { + .name = DRIVER_NAME, + .owner = THIS_MODULE, + .of_match_table = bcm2835_smi_of_match, + }, +}; + +module_platform_driver(bcm2835_smi_driver); + +MODULE_ALIAS("platform:smi-bcm2835"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Device driver for BCM2835's secondary memory interface"); +MODULE_AUTHOR("Luke Wren "); diff --git a/include/linux/broadcom/bcm2835_smi.h b/include/linux/broadcom/bcm2835_smi.h new file mode 100644 index 0000000..ee3a75e --- /dev/null +++ b/include/linux/broadcom/bcm2835_smi.h @@ -0,0 +1,391 @@ +/** + * Declarations and definitions for Broadcom's Secondary Memory Interface + * + * Written by Luke Wren + * Copyright (c) 2015, Raspberry Pi (Trading) Ltd. + * Copyright (c) 2010-2012 Broadcom. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions, and the following disclaimer, + * without modification. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The names of the above-listed copyright holders may not be used + * to endorse or promote products derived from this software without + * specific prior written permission. + * + * ALTERNATIVELY, this software may be distributed under the terms of the + * GNU General Public License ("GPL") version 2, as published by the Free + * Software Foundation. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS + * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef BCM2835_SMI_H +#define BCM2835_SMI_H + +#include + +#ifndef __KERNEL__ +#include +#include +#endif + +#define BCM2835_SMI_IOC_MAGIC 0x1 +#define BCM2835_SMI_INVALID_HANDLE (~0) + +/* IOCTLs 0x100...0x1ff are not device-specific - we can use them */ +#define BCM2835_SMI_IOC_GET_SETTINGS _IO(BCM2835_SMI_IOC_MAGIC, 0) +#define BCM2835_SMI_IOC_WRITE_SETTINGS _IO(BCM2835_SMI_IOC_MAGIC, 1) +#define BCM2835_SMI_IOC_ADDRESS _IO(BCM2835_SMI_IOC_MAGIC, 2) +#define BCM2835_SMI_IOC_MAX 2 + +#define SMI_WIDTH_8BIT 0 +#define SMI_WIDTH_16BIT 1 +#define SMI_WIDTH_9BIT 2 +#define SMI_WIDTH_18BIT 3 + +/* max number of bytes where DMA will not be used */ +#define DMA_THRESHOLD_BYTES 128 +#define DMA_BOUNCE_BUFFER_SIZE (1024 * 1024 / 2) +#define DMA_BOUNCE_BUFFER_COUNT 3 + + +struct smi_settings { + int data_width; + /* Whether or not to pack multiple SMI transfers into a + single 32 bit FIFO word */ + bool pack_data; + + /* Timing for reads (writes the same but for WE) + * + * OE ----------+ +-------------------- + * | | + * +----------+ + * SD -<==============================>----------- + * SA -<=========================================>- + * <-setup-> <-strobe -> <-hold -> <- pace -> + */ + + int read_setup_time; + int read_hold_time; + int read_pace_time; + int read_strobe_time; + + int write_setup_time; + int write_hold_time; + int write_pace_time; + int write_strobe_time; + + bool dma_enable; /* DREQs */ + bool dma_passthrough_enable; /* External DREQs */ + int dma_read_thresh; + int dma_write_thresh; + int dma_panic_read_thresh; + int dma_panic_write_thresh; +}; + +/**************************************************************************** +* +* Declare exported SMI functions +* +***************************************************************************/ + +#ifdef __KERNEL__ + +#include /* for enum dma_transfer_direction */ +#include +#include + +struct bcm2835_smi_instance; + +struct bcm2835_smi_bounce_info { + struct semaphore callback_sem; + void *buffer[DMA_BOUNCE_BUFFER_COUNT]; + dma_addr_t phys[DMA_BOUNCE_BUFFER_COUNT]; + struct scatterlist sgl[DMA_BOUNCE_BUFFER_COUNT]; +}; + + +void bcm2835_smi_set_regs_from_settings(struct bcm2835_smi_instance *); + +struct smi_settings *bcm2835_smi_get_settings_from_regs( + struct bcm2835_smi_instance *inst); + +void bcm2835_smi_write_buf( + struct bcm2835_smi_instance *inst, + const void *buf, + size_t n_bytes); + +void bcm2835_smi_read_buf( + struct bcm2835_smi_instance *inst, + void *buf, + size_t n_bytes); + +void bcm2835_smi_set_address(struct bcm2835_smi_instance *inst, + unsigned int address); + +ssize_t bcm2835_smi_user_dma( + struct bcm2835_smi_instance *inst, + enum dma_transfer_direction dma_dir, + char __user *user_ptr, + size_t count, + struct bcm2835_smi_bounce_info **bounce); + +struct bcm2835_smi_instance *bcm2835_smi_get(struct device_node *node); + +#endif /* __KERNEL__ */ + +/**************************************************************** +* +* Implementation-only declarations +* +****************************************************************/ + +#ifdef BCM2835_SMI_IMPLEMENTATION + +/* Clock manager registers for SMI clock: */ +#define CM_SMI_BASE_ADDRESS ((BCM2708_PERI_BASE) + 0x1010b0) +/* Clock manager "password" to protect registers from spurious writes */ +#define CM_PWD (0x5a << 24) + +#define CM_SMI_CTL 0x00 +#define CM_SMI_DIV 0x04 + +#define CM_SMI_CTL_FLIP (1 << 8) +#define CM_SMI_CTL_BUSY (1 << 7) +#define CM_SMI_CTL_KILL (1 << 5) +#define CM_SMI_CTL_ENAB (1 << 4) +#define CM_SMI_CTL_SRC_MASK (0xf) +#define CM_SMI_CTL_SRC_OFFS (0) + +#define CM_SMI_DIV_DIVI_MASK (0xf << 12) +#define CM_SMI_DIV_DIVI_OFFS (12) +#define CM_SMI_DIV_DIVF_MASK (0xff << 4) +#define CM_SMI_DIV_DIVF_OFFS (4) + +/* SMI register mapping:*/ +#define SMI_BASE_ADDRESS ((BCM2708_PERI_BASE) + 0x600000) + +#define SMICS 0x00 /* control + status register */ +#define SMIL 0x04 /* length/count (n external txfers) */ +#define SMIA 0x08 /* address register */ +#define SMID 0x0c /* data register */ +#define SMIDSR0 0x10 /* device 0 read settings */ +#define SMIDSW0 0x14 /* device 0 write settings */ +#define SMIDSR1 0x18 /* device 1 read settings */ +#define SMIDSW1 0x1c /* device 1 write settings */ +#define SMIDSR2 0x20 /* device 2 read settings */ +#define SMIDSW2 0x24 /* device 2 write settings */ +#define SMIDSR3 0x28 /* device 3 read settings */ +#define SMIDSW3 0x2c /* device 3 write settings */ +#define SMIDC 0x30 /* DMA control registers */ +#define SMIDCS 0x34 /* direct control/status register */ +#define SMIDA 0x38 /* direct address register */ +#define SMIDD 0x3c /* direct data registers */ +#define SMIFD 0x40 /* FIFO debug register */ + + + +/* Control and Status register bits: + * SMICS_RXF : RX fifo full: 1 when RX fifo is full + * SMICS_TXE : TX fifo empty: 1 when empty. + * SMICS_RXD : RX fifo contains data: 1 when there is data. + * SMICS_TXD : TX fifo can accept data: 1 when true. + * SMICS_RXR : RX fifo needs reading: 1 when fifo more than 3/4 full, or + * when "DONE" and fifo not emptied. + * SMICS_TXW : TX fifo needs writing: 1 when less than 1/4 full. + * SMICS_AFERR : AXI FIFO error: 1 when fifo read when empty or written + * when full. Write 1 to clear. + * SMICS_EDREQ : 1 when external DREQ received. + * SMICS_PXLDAT : Pixel data: write 1 to enable pixel transfer modes. + * SMICS_SETERR : 1 if there was an error writing to setup regs (e.g. + * tx was in progress). Write 1 to clear. + * SMICS_PVMODE : Set to 1 to enable pixel valve mode. + * SMICS_INTR : Set to 1 to enable interrupt on RX. + * SMICS_INTT : Set to 1 to enable interrupt on TX. + * SMICS_INTD : Set to 1 to enable interrupt on DONE condition. + * SMICS_TEEN : Tear effect mode enabled: Programmed transfers will wait + * for a TE trigger before writing. + * SMICS_PAD1 : Padding settings for external transfers. For writes: the + * number of bytes initially written to the TX fifo that + * SMICS_PAD0 : should be ignored. For reads: the number of bytes that will + * be read before the data, and should be dropped. + * SMICS_WRITE : Transfer direction: 1 = write to external device, 0 = read + * SMICS_CLEAR : Write 1 to clear the FIFOs. + * SMICS_START : Write 1 to start the programmed transfer. + * SMICS_ACTIVE : Reads as 1 when a programmed transfer is underway. + * SMICS_DONE : Reads as 1 when transfer finished. For RX, not set until + * FIFO emptied. + * SMICS_ENABLE : Set to 1 to enable the SMI peripheral, 0 to disable. + */ + +#define SMICS_RXF (1 << 31) +#define SMICS_TXE (1 << 30) +#define SMICS_RXD (1 << 29) +#define SMICS_TXD (1 << 28) +#define SMICS_RXR (1 << 27) +#define SMICS_TXW (1 << 26) +#define SMICS_AFERR (1 << 25) +#define SMICS_EDREQ (1 << 15) +#define SMICS_PXLDAT (1 << 14) +#define SMICS_SETERR (1 << 13) +#define SMICS_PVMODE (1 << 12) +#define SMICS_INTR (1 << 11) +#define SMICS_INTT (1 << 10) +#define SMICS_INTD (1 << 9) +#define SMICS_TEEN (1 << 8) +#define SMICS_PAD1 (1 << 7) +#define SMICS_PAD0 (1 << 6) +#define SMICS_WRITE (1 << 5) +#define SMICS_CLEAR (1 << 4) +#define SMICS_START (1 << 3) +#define SMICS_ACTIVE (1 << 2) +#define SMICS_DONE (1 << 1) +#define SMICS_ENABLE (1 << 0) + +/* Address register bits: */ + +#define SMIA_DEVICE_MASK ((1 << 9) | (1 << 8)) +#define SMIA_DEVICE_OFFS (8) +#define SMIA_ADDR_MASK (0x3f) /* bits 5 -> 0 */ +#define SMIA_ADDR_OFFS (0) + +/* DMA control register bits: + * SMIDC_DMAEN : DMA enable: set 1: DMA requests will be issued. + * SMIDC_DMAP : DMA passthrough: when set to 0, top two data pins are used by + * SMI as usual. When set to 1, the top two pins are used for + * external DREQs: pin 16 read request, 17 write. + * SMIDC_PANIC* : Threshold at which DMA will panic during read/write. + * SMIDC_REQ* : Threshold at which DMA will generate a DREQ. + */ + +#define SMIDC_DMAEN (1 << 28) +#define SMIDC_DMAP (1 << 24) +#define SMIDC_PANICR_MASK (0x3f << 18) +#define SMIDC_PANICR_OFFS (18) +#define SMIDC_PANICW_MASK (0x3f << 12) +#define SMIDC_PANICW_OFFS (12) +#define SMIDC_REQR_MASK (0x3f << 6) +#define SMIDC_REQR_OFFS (6) +#define SMIDC_REQW_MASK (0x3f) +#define SMIDC_REQW_OFFS (0) + +/* Device settings register bits: same for all 4 (or 3?) device register sets. + * Device read settings: + * SMIDSR_RWIDTH : Read transfer width. 00 = 8bit, 01 = 16bit, + * 10 = 18bit, 11 = 9bit. + * SMIDSR_RSETUP : Read setup time: number of core cycles between chip + * select/address and read strobe. Min 1, max 64. + * SMIDSR_MODE68 : 1 for System 68 mode (i.e. enable + direction pins, + * rather than OE + WE pin) + * SMIDSR_FSETUP : If set to 1, setup time only applies to first + * transfer after address change. + * SMIDSR_RHOLD : Number of core cycles between read strobe going + * inactive and CS/address going inactive. Min 1, max 64 + * SMIDSR_RPACEALL : When set to 1, this device's RPACE value will always + * be used for the next transaction, even if it is not + * to this device. + * SMIDSR_RPACE : Number of core cycles spent waiting between CS + * deassert and start of next transfer. Min 1, max 128 + * SMIDSR_RDREQ : 1 = use external DMA request on SD16 to pace reads + * from device. Must also set DMAP in SMICS. + * SMIDSR_RSTROBE : Number of cycles to assert the read strobe. + * min 1, max 128. + */ +#define SMIDSR_RWIDTH_MASK ((1<<31)|(1<<30)) +#define SMIDSR_RWIDTH_OFFS (30) +#define SMIDSR_RSETUP_MASK (0x3f << 24) +#define SMIDSR_RSETUP_OFFS (24) +#define SMIDSR_MODE68 (1 << 23) +#define SMIDSR_FSETUP (1 << 22) +#define SMIDSR_RHOLD_MASK (0x3f << 16) +#define SMIDSR_RHOLD_OFFS (16) +#define SMIDSR_RPACEALL (1 << 15) +#define SMIDSR_RPACE_MASK (0x7f << 8) +#define SMIDSR_RPACE_OFFS (8) +#define SMIDSR_RDREQ (1 << 7) +#define SMIDSR_RSTROBE_MASK (0x7f) +#define SMIDSR_RSTROBE_OFFS (0) + +/* Device write settings: + * SMIDSW_WWIDTH : Write transfer width. 00 = 8bit, 01 = 16bit, + * 10= 18bit, 11 = 9bit. + * SMIDSW_WSETUP : Number of cycles between CS assert and write strobe. + * Min 1, max 64. + * SMIDSW_WFORMAT : Pixel format of input. 0 = 16bit RGB 565, + * 1 = 32bit RGBA 8888 + * SMIDSW_WSWAP : 1 = swap pixel data bits. (Use with SMICS_PXLDAT) + * SMIDSW_WHOLD : Time between WE deassert and CS deassert. 1 to 64 + * SMIDSW_WPACEALL : 1: this device's WPACE will be used for the next + * transfer, regardless of that transfer's device. + * SMIDSW_WPACE : Cycles between CS deassert and next CS assert. + * Min 1, max 128 + * SMIDSW_WDREQ : Use external DREQ on pin 17 to pace writes. DMAP must + * be set in SMICS. + * SMIDSW_WSTROBE : Number of cycles to assert the write strobe. + * Min 1, max 128 + */ +#define SMIDSW_WWIDTH_MASK ((1<<31)|(1<<30)) +#define SMIDSW_WWIDTH_OFFS (30) +#define SMIDSW_WSETUP_MASK (0x3f << 24) +#define SMIDSW_WSETUP_OFFS (24) +#define SMIDSW_WFORMAT (1 << 23) +#define SMIDSW_WSWAP (1 << 22) +#define SMIDSW_WHOLD_MASK (0x3f << 16) +#define SMIDSW_WHOLD_OFFS (16) +#define SMIDSW_WPACEALL (1 << 15) +#define SMIDSW_WPACE_MASK (0x7f << 8) +#define SMIDSW_WPACE_OFFS (8) +#define SMIDSW_WDREQ (1 << 7) +#define SMIDSW_WSTROBE_MASK (0x7f) +#define SMIDSW_WSTROBE_OFFS (0) + +/* Direct transfer control + status register + * SMIDCS_WRITE : Direction of transfer: 1 -> write, 0 -> read + * SMIDCS_DONE : 1 when a transfer has finished. Write 1 to clear. + * SMIDCS_START : Write 1 to start a transfer, if one is not already underway. + * SMIDCE_ENABLE: Write 1 to enable SMI in direct mode. + */ + +#define SMIDCS_WRITE (1 << 3) +#define SMIDCS_DONE (1 << 2) +#define SMIDCS_START (1 << 1) +#define SMIDCS_ENABLE (1 << 0) + +/* Direct transfer address register + * SMIDA_DEVICE : Indicates which of the device settings banks should be used. + * SMIDA_ADDR : The value to be asserted on the address pins. + */ + +#define SMIDA_DEVICE_MASK ((1<<9)|(1<<8)) +#define SMIDA_DEVICE_OFFS (8) +#define SMIDA_ADDR_MASK (0x3f) +#define SMIDA_ADDR_OFFS (0) + +/* FIFO debug register + * SMIFD_FLVL : The high-tide mark of FIFO count during the most recent txfer + * SMIFD_FCNT : The current FIFO count. + */ +#define SMIFD_FLVL_MASK (0x3f << 8) +#define SMIFD_FLVL_OFFS (8) +#define SMIFD_FCNT_MASK (0x3f) +#define SMIFD_FCNT_OFFS (0) + +#endif /* BCM2835_SMI_IMPLEMENTATION */ + +#endif /* BCM2835_SMI_H */ -- 2.7.4