+++ /dev/null
-/*
- * Copyright(c) 2015, 2016 Intel Corporation.
- *
- * This file is provided under a dual BSD/GPLv2 license. When using or
- * redistributing this file, you may do so under either license.
- *
- * GPL LICENSE SUMMARY
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of version 2 of the GNU General Public License as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * BSD LICENSE
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * - Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * - 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.
- * - Neither the name of Intel Corporation nor the names of its
- * contributors may be used to endorse or promote products derived
- * from this software without specific prior written permission.
- *
- * 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 <linux/delay.h>
-#include <linux/pci.h>
-#include <linux/vmalloc.h>
-
-#include "hfi.h"
-#include "twsi.h"
-
-/*
- * "Two Wire Serial Interface" support.
- *
- * Originally written for a not-quite-i2c serial eeprom, which is
- * still used on some supported boards. Later boards have added a
- * variety of other uses, most board-specific, so the bit-boffing
- * part has been split off to this file, while the other parts
- * have been moved to chip-specific files.
- *
- * We have also dropped all pretense of fully generic (e.g. pretend
- * we don't know whether '1' is the higher voltage) interface, as
- * the restrictions of the generic i2c interface (e.g. no access from
- * driver itself) make it unsuitable for this use.
- */
-
-#define READ_CMD 1
-#define WRITE_CMD 0
-
-/**
- * i2c_wait_for_writes - wait for a write
- * @dd: the hfi1_ib device
- *
- * We use this instead of udelay directly, so we can make sure
- * that previous register writes have been flushed all the way
- * to the chip. Since we are delaying anyway, the cost doesn't
- * hurt, and makes the bit twiddling more regular
- */
-static void i2c_wait_for_writes(struct hfi1_devdata *dd, u32 target)
-{
- /*
- * implicit read of EXTStatus is as good as explicit
- * read of scratch, if all we want to do is flush
- * writes.
- */
- hfi1_gpio_mod(dd, target, 0, 0, 0);
- rmb(); /* inlined, so prevent compiler reordering */
-}
-
-/*
- * QSFP modules are allowed to hold SCL low for 500uSec. Allow twice that
- * for "almost compliant" modules
- */
-#define SCL_WAIT_USEC 1000
-
-/* BUF_WAIT is time bus must be free between STOP or ACK and to next START.
- * Should be 20, but some chips need more.
- */
-#define TWSI_BUF_WAIT_USEC 60
-
-static void scl_out(struct hfi1_devdata *dd, u32 target, u8 bit)
-{
- u32 mask;
-
- udelay(1);
-
- mask = QSFP_HFI0_I2CCLK;
-
- /* SCL is meant to be bare-drain, so never set "OUT", just DIR */
- hfi1_gpio_mod(dd, target, 0, bit ? 0 : mask, mask);
-
- /*
- * Allow for slow slaves by simple
- * delay for falling edge, sampling on rise.
- */
- if (!bit) {
- udelay(2);
- } else {
- int rise_usec;
-
- for (rise_usec = SCL_WAIT_USEC; rise_usec > 0; rise_usec -= 2) {
- if (mask & hfi1_gpio_mod(dd, target, 0, 0, 0))
- break;
- udelay(2);
- }
- if (rise_usec <= 0)
- dd_dev_err(dd, "SCL interface stuck low > %d uSec\n",
- SCL_WAIT_USEC);
- }
- i2c_wait_for_writes(dd, target);
-}
-
-static u8 scl_in(struct hfi1_devdata *dd, u32 target, int wait)
-{
- u32 read_val, mask;
-
- mask = QSFP_HFI0_I2CCLK;
- /* SCL is meant to be bare-drain, so never set "OUT", just DIR */
- hfi1_gpio_mod(dd, target, 0, 0, mask);
- read_val = hfi1_gpio_mod(dd, target, 0, 0, 0);
- if (wait)
- i2c_wait_for_writes(dd, target);
- return (read_val & mask) >> GPIO_SCL_NUM;
-}
-
-static void sda_out(struct hfi1_devdata *dd, u32 target, u8 bit)
-{
- u32 mask;
-
- mask = QSFP_HFI0_I2CDAT;
-
- /* SDA is meant to be bare-drain, so never set "OUT", just DIR */
- hfi1_gpio_mod(dd, target, 0, bit ? 0 : mask, mask);
-
- i2c_wait_for_writes(dd, target);
- udelay(2);
-}
-
-static u8 sda_in(struct hfi1_devdata *dd, u32 target, int wait)
-{
- u32 read_val, mask;
-
- mask = QSFP_HFI0_I2CDAT;
- /* SDA is meant to be bare-drain, so never set "OUT", just DIR */
- hfi1_gpio_mod(dd, target, 0, 0, mask);
- read_val = hfi1_gpio_mod(dd, target, 0, 0, 0);
- if (wait)
- i2c_wait_for_writes(dd, target);
- return (read_val & mask) >> GPIO_SDA_NUM;
-}
-
-/**
- * i2c_ackrcv - see if ack following write is true
- * @dd: the hfi1_ib device
- */
-static int i2c_ackrcv(struct hfi1_devdata *dd, u32 target)
-{
- u8 ack_received;
-
- /* AT ENTRY SCL = LOW */
- /* change direction, ignore data */
- ack_received = sda_in(dd, target, 1);
- scl_out(dd, target, 1);
- ack_received = sda_in(dd, target, 1) == 0;
- scl_out(dd, target, 0);
- return ack_received;
-}
-
-static void stop_cmd(struct hfi1_devdata *dd, u32 target);
-
-/**
- * rd_byte - read a byte, sending STOP on last, else ACK
- * @dd: the hfi1_ib device
- *
- * Returns byte shifted out of device
- */
-static int rd_byte(struct hfi1_devdata *dd, u32 target, int last)
-{
- int bit_cntr, data;
-
- data = 0;
-
- for (bit_cntr = 7; bit_cntr >= 0; --bit_cntr) {
- data <<= 1;
- scl_out(dd, target, 1);
- data |= sda_in(dd, target, 0);
- scl_out(dd, target, 0);
- }
- if (last) {
- scl_out(dd, target, 1);
- stop_cmd(dd, target);
- } else {
- sda_out(dd, target, 0);
- scl_out(dd, target, 1);
- scl_out(dd, target, 0);
- sda_out(dd, target, 1);
- }
- return data;
-}
-
-/**
- * wr_byte - write a byte, one bit at a time
- * @dd: the hfi1_ib device
- * @data: the byte to write
- *
- * Returns 0 if we got the following ack, otherwise 1
- */
-static int wr_byte(struct hfi1_devdata *dd, u32 target, u8 data)
-{
- int bit_cntr;
- u8 bit;
-
- for (bit_cntr = 7; bit_cntr >= 0; bit_cntr--) {
- bit = (data >> bit_cntr) & 1;
- sda_out(dd, target, bit);
- scl_out(dd, target, 1);
- scl_out(dd, target, 0);
- }
- return (!i2c_ackrcv(dd, target)) ? 1 : 0;
-}
-
-/*
- * issue TWSI start sequence:
- * (both clock/data high, clock high, data low while clock is high)
- */
-static void start_seq(struct hfi1_devdata *dd, u32 target)
-{
- sda_out(dd, target, 1);
- scl_out(dd, target, 1);
- sda_out(dd, target, 0);
- udelay(1);
- scl_out(dd, target, 0);
-}
-
-/**
- * stop_seq - transmit the stop sequence
- * @dd: the hfi1_ib device
- *
- * (both clock/data low, clock high, data high while clock is high)
- */
-static void stop_seq(struct hfi1_devdata *dd, u32 target)
-{
- scl_out(dd, target, 0);
- sda_out(dd, target, 0);
- scl_out(dd, target, 1);
- sda_out(dd, target, 1);
-}
-
-/**
- * stop_cmd - transmit the stop condition
- * @dd: the hfi1_ib device
- *
- * (both clock/data low, clock high, data high while clock is high)
- */
-static void stop_cmd(struct hfi1_devdata *dd, u32 target)
-{
- stop_seq(dd, target);
- udelay(TWSI_BUF_WAIT_USEC);
-}
-
-/**
- * hfi1_twsi_reset - reset I2C communication
- * @dd: the hfi1_ib device
- * returns 0 if ok, -EIO on error
- */
-int hfi1_twsi_reset(struct hfi1_devdata *dd, u32 target)
-{
- int clock_cycles_left = 9;
- u32 mask;
-
- /* Both SCL and SDA should be high. If not, there
- * is something wrong.
- */
- mask = QSFP_HFI0_I2CCLK | QSFP_HFI0_I2CDAT;
-
- /*
- * Force pins to desired innocuous state.
- * This is the default power-on state with out=0 and dir=0,
- * So tri-stated and should be floating high (barring HW problems)
- */
- hfi1_gpio_mod(dd, target, 0, 0, mask);
-
- /* Check if SCL is low, if it is low then we have a slave device
- * misbehaving and there is not much we can do.
- */
- if (!scl_in(dd, target, 0))
- return -EIO;
-
- /* Check if SDA is low, if it is low then we have to clock SDA
- * up to 9 times for the device to release the bus
- */
- while (clock_cycles_left--) {
- if (sda_in(dd, target, 0))
- return 0;
- scl_out(dd, target, 0);
- scl_out(dd, target, 1);
- }
-
- return -EIO;
-}
-
-#define HFI1_TWSI_START 0x100
-#define HFI1_TWSI_STOP 0x200
-
-/* Write byte to TWSI, optionally prefixed with START or suffixed with
- * STOP.
- * returns 0 if OK (ACK received), else != 0
- */
-static int twsi_wr(struct hfi1_devdata *dd, u32 target, int data, int flags)
-{
- int ret = 1;
-
- if (flags & HFI1_TWSI_START)
- start_seq(dd, target);
-
- /* Leaves SCL low (from i2c_ackrcv()) */
- ret = wr_byte(dd, target, data);
-
- if (flags & HFI1_TWSI_STOP)
- stop_cmd(dd, target);
- return ret;
-}
-
-/* Added functionality for IBA7220-based cards */
-#define HFI1_TEMP_DEV 0x98
-
-/*
- * hfi1_twsi_blk_rd
- * General interface for data transfer from twsi devices.
- * One vestige of its former role is that it recognizes a device
- * HFI1_TWSI_NO_DEV and does the correct operation for the legacy part,
- * which responded to all TWSI device codes, interpreting them as
- * address within device. On all other devices found on board handled by
- * this driver, the device is followed by a N-byte "address" which selects
- * the "register" or "offset" within the device from which data should
- * be read.
- */
-int hfi1_twsi_blk_rd(struct hfi1_devdata *dd, u32 target, int dev, int addr,
- void *buffer, int len)
-{
- u8 *bp = buffer;
- int ret = 1;
- int i;
- int offset_size;
-
- /* obtain the offset size, strip it from the device address */
- offset_size = (dev >> 8) & 0xff;
- dev &= 0xff;
-
- /* allow at most a 2 byte offset */
- if (offset_size > 2)
- goto bail;
-
- if (dev == HFI1_TWSI_NO_DEV) {
- /* legacy not-really-I2C */
- addr = (addr << 1) | READ_CMD;
- ret = twsi_wr(dd, target, addr, HFI1_TWSI_START);
- } else {
- /* Actual I2C */
- if (offset_size) {
- ret = twsi_wr(dd, target,
- dev | WRITE_CMD, HFI1_TWSI_START);
- if (ret) {
- stop_cmd(dd, target);
- goto bail;
- }
-
- for (i = 0; i < offset_size; i++) {
- ret = twsi_wr(dd, target,
- (addr >> (i * 8)) & 0xff, 0);
- udelay(TWSI_BUF_WAIT_USEC);
- if (ret) {
- dd_dev_err(dd, "Failed to write byte %d of offset 0x%04X\n",
- i, addr);
- goto bail;
- }
- }
- }
- ret = twsi_wr(dd, target, dev | READ_CMD, HFI1_TWSI_START);
- }
- if (ret) {
- stop_cmd(dd, target);
- goto bail;
- }
-
- /*
- * block devices keeps clocking data out as long as we ack,
- * automatically incrementing the address. Some have "pages"
- * whose boundaries will not be crossed, but the handling
- * of these is left to the caller, who is in a better
- * position to know.
- */
- while (len-- > 0) {
- /*
- * Get and store data, sending ACK if length remaining,
- * else STOP
- */
- *bp++ = rd_byte(dd, target, !len);
- }
-
- ret = 0;
-
-bail:
- return ret;
-}
-
-/*
- * hfi1_twsi_blk_wr
- * General interface for data transfer to twsi devices.
- * One vestige of its former role is that it recognizes a device
- * HFI1_TWSI_NO_DEV and does the correct operation for the legacy part,
- * which responded to all TWSI device codes, interpreting them as
- * address within device. On all other devices found on board handled by
- * this driver, the device is followed by a N-byte "address" which selects
- * the "register" or "offset" within the device to which data should
- * be written.
- */
-int hfi1_twsi_blk_wr(struct hfi1_devdata *dd, u32 target, int dev, int addr,
- const void *buffer, int len)
-{
- const u8 *bp = buffer;
- int ret = 1;
- int i;
- int offset_size;
-
- /* obtain the offset size, strip it from the device address */
- offset_size = (dev >> 8) & 0xff;
- dev &= 0xff;
-
- /* allow at most a 2 byte offset */
- if (offset_size > 2)
- goto bail;
-
- if (dev == HFI1_TWSI_NO_DEV) {
- if (twsi_wr(dd, target, (addr << 1) | WRITE_CMD,
- HFI1_TWSI_START)) {
- goto failed_write;
- }
- } else {
- /* Real I2C */
- if (twsi_wr(dd, target, dev | WRITE_CMD, HFI1_TWSI_START))
- goto failed_write;
- }
-
- for (i = 0; i < offset_size; i++) {
- ret = twsi_wr(dd, target, (addr >> (i * 8)) & 0xff, 0);
- udelay(TWSI_BUF_WAIT_USEC);
- if (ret) {
- dd_dev_err(dd, "Failed to write byte %d of offset 0x%04X\n",
- i, addr);
- goto bail;
- }
- }
-
- for (i = 0; i < len; i++)
- if (twsi_wr(dd, target, *bp++, 0))
- goto failed_write;
-
- ret = 0;
-
-failed_write:
- stop_cmd(dd, target);
-
-bail:
- return ret;
-}
projects / platform / kernel / linux-rpi3.git / commitdiff