From 2aba2f2a704d368583e832555b25d88265e62b6d Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Mon, 21 Oct 2019 01:00:42 +0200 Subject: [PATCH] mtd: physmap_of: add a hook for Intel IXP4xx flash probing In order to support device tree probing of IXP4xx NOR flash chips, a certain big-endian or mixed-endian memory access pattern need to be used. I have opted to use the pattern set by previous plug-ins to physmap for Gemini and Versatile, just override some functions and reuse most of the physmap core code as it is to minimize maintenance. Parts of drivers/mtd/ixp4xx.c are copied into this file. After we have IXP4xx converted fully to device tree, the drivers/mtd/ixp4xx.c file will be deleted and this will be the only access pattern to the IXP4xx flash. I did not keep the quirk in the flash write function after probe, where the old code for a while checks for access to odd addresses, fails and assigns a "faster" write function once it has convinced probe to only use 2-byte accesses. As we mandate that this device should be using bank-width = <2> this should not be a problem unless misconfigured. Signed-off-by: Linus Walleij Signed-off-by: Miquel Raynal --- drivers/mtd/maps/Kconfig | 11 ++++ drivers/mtd/maps/Makefile | 1 + drivers/mtd/maps/physmap-core.c | 5 ++ drivers/mtd/maps/physmap-ixp4xx.c | 132 ++++++++++++++++++++++++++++++++++++++ drivers/mtd/maps/physmap-ixp4xx.h | 17 +++++ 5 files changed, 166 insertions(+) create mode 100644 drivers/mtd/maps/physmap-ixp4xx.c create mode 100644 drivers/mtd/maps/physmap-ixp4xx.h diff --git a/drivers/mtd/maps/Kconfig b/drivers/mtd/maps/Kconfig index bc82305..b28225a 100644 --- a/drivers/mtd/maps/Kconfig +++ b/drivers/mtd/maps/Kconfig @@ -96,6 +96,17 @@ config MTD_PHYSMAP_GEMINI platforms, some detection and setting up parallel mode on the external interface. +config MTD_PHYSMAP_IXP4XX + bool "Intel IXP4xx OF-based physical memory map handling" + depends on MTD_PHYSMAP_OF + depends on ARM + select MTD_COMPLEX_MAPPINGS + select MTD_CFI_BE_BYTE_SWAP if CPU_BIG_ENDIAN + default ARCH_IXP4XX + help + This provides some extra DT physmap parsing for the Intel IXP4xx + platforms, some elaborate endianness handling in particular. + config MTD_PHYSMAP_GPIO_ADDR bool "GPIO-assisted Flash Chip Support" depends on MTD_PHYSMAP diff --git a/drivers/mtd/maps/Makefile b/drivers/mtd/maps/Makefile index 1146009..c0da86a 100644 --- a/drivers/mtd/maps/Makefile +++ b/drivers/mtd/maps/Makefile @@ -20,6 +20,7 @@ obj-$(CONFIG_MTD_PXA2XX) += pxa2xx-flash.o physmap-objs-y += physmap-core.o physmap-objs-$(CONFIG_MTD_PHYSMAP_VERSATILE) += physmap-versatile.o physmap-objs-$(CONFIG_MTD_PHYSMAP_GEMINI) += physmap-gemini.o +physmap-objs-$(CONFIG_MTD_PHYSMAP_IXP4XX) += physmap-ixp4xx.o physmap-objs := $(physmap-objs-y) obj-$(CONFIG_MTD_PHYSMAP) += physmap.o obj-$(CONFIG_MTD_PISMO) += pismo.o diff --git a/drivers/mtd/maps/physmap-core.c b/drivers/mtd/maps/physmap-core.c index 21b556a..a9f7964 100644 --- a/drivers/mtd/maps/physmap-core.c +++ b/drivers/mtd/maps/physmap-core.c @@ -41,6 +41,7 @@ #include #include "physmap-gemini.h" +#include "physmap-ixp4xx.h" #include "physmap-versatile.h" struct physmap_flash_info { @@ -370,6 +371,10 @@ static int physmap_flash_of_init(struct platform_device *dev) if (err) return err; + err = of_flash_probe_ixp4xx(dev, dp, &info->maps[i]); + if (err) + return err; + err = of_flash_probe_versatile(dev, dp, &info->maps[i]); if (err) return err; diff --git a/drivers/mtd/maps/physmap-ixp4xx.c b/drivers/mtd/maps/physmap-ixp4xx.c new file mode 100644 index 0000000..6a05422 --- /dev/null +++ b/drivers/mtd/maps/physmap-ixp4xx.c @@ -0,0 +1,132 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Intel IXP4xx OF physmap add-on + * Copyright (C) 2019 Linus Walleij + * + * Based on the ixp4xx.c map driver, originally written by: + * Intel Corporation + * Deepak Saxena + * Copyright (C) 2002 Intel Corporation + * Copyright (C) 2003-2004 MontaVista Software, Inc. + */ +#include +#include +#include +#include +#include +#include "physmap-ixp4xx.h" + +/* + * Read/write a 16 bit word from flash address 'addr'. + * + * When the cpu is in little-endian mode it swizzles the address lines + * ('address coherency') so we need to undo the swizzling to ensure commands + * and the like end up on the correct flash address. + * + * To further complicate matters, due to the way the expansion bus controller + * handles 32 bit reads, the byte stream ABCD is stored on the flash as: + * D15 D0 + * +---+---+ + * | A | B | 0 + * +---+---+ + * | C | D | 2 + * +---+---+ + * This means that on LE systems each 16 bit word must be swapped. Note that + * this requires CONFIG_MTD_CFI_BE_BYTE_SWAP to be enabled to 'unswap' the CFI + * data and other flash commands which are always in D7-D0. + */ +#ifndef CONFIG_CPU_BIG_ENDIAN + +static inline u16 flash_read16(void __iomem *addr) +{ + return be16_to_cpu(__raw_readw((void __iomem *)((unsigned long)addr ^ 0x2))); +} + +static inline void flash_write16(u16 d, void __iomem *addr) +{ + __raw_writew(cpu_to_be16(d), (void __iomem *)((unsigned long)addr ^ 0x2)); +} + +#define BYTE0(h) ((h) & 0xFF) +#define BYTE1(h) (((h) >> 8) & 0xFF) + +#else + +static inline u16 flash_read16(const void __iomem *addr) +{ + return __raw_readw(addr); +} + +static inline void flash_write16(u16 d, void __iomem *addr) +{ + __raw_writew(d, addr); +} + +#define BYTE0(h) (((h) >> 8) & 0xFF) +#define BYTE1(h) ((h) & 0xFF) +#endif + +static map_word ixp4xx_read16(struct map_info *map, unsigned long ofs) +{ + map_word val; + + val.x[0] = flash_read16(map->virt + ofs); + return val; +} + +/* + * The IXP4xx expansion bus only allows 16-bit wide acceses + * when attached to a 16-bit wide device (such as the 28F128J3A), + * so we can't just memcpy_fromio(). + */ +static void ixp4xx_copy_from(struct map_info *map, void *to, + unsigned long from, ssize_t len) +{ + u8 *dest = (u8 *) to; + void __iomem *src = map->virt + from; + + if (len <= 0) + return; + + if (from & 1) { + *dest++ = BYTE1(flash_read16(src-1)); + src++; + --len; + } + + while (len >= 2) { + u16 data = flash_read16(src); + *dest++ = BYTE0(data); + *dest++ = BYTE1(data); + src += 2; + len -= 2; + } + + if (len > 0) + *dest++ = BYTE0(flash_read16(src)); +} + +static void ixp4xx_write16(struct map_info *map, map_word d, unsigned long adr) +{ + flash_write16(d.x[0], map->virt + adr); +} + +int of_flash_probe_ixp4xx(struct platform_device *pdev, + struct device_node *np, + struct map_info *map) +{ + struct device *dev = &pdev->dev; + + /* Multiplatform guard */ + if (!of_device_is_compatible(np, "intel,ixp4xx-flash")) + return 0; + + map->read = ixp4xx_read16; + map->write = ixp4xx_write16; + map->copy_from = ixp4xx_copy_from; + map->copy_to = NULL; + + dev_info(dev, "initialized Intel IXP4xx-specific physmap control\n"); + + return 0; +} diff --git a/drivers/mtd/maps/physmap-ixp4xx.h b/drivers/mtd/maps/physmap-ixp4xx.h new file mode 100644 index 0000000..b0fc49b --- /dev/null +++ b/drivers/mtd/maps/physmap-ixp4xx.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include +#include + +#ifdef CONFIG_MTD_PHYSMAP_IXP4XX +int of_flash_probe_ixp4xx(struct platform_device *pdev, + struct device_node *np, + struct map_info *map); +#else +static inline +int of_flash_probe_ixp4xx(struct platform_device *pdev, + struct device_node *np, + struct map_info *map) +{ + return 0; +} +#endif -- 2.7.4