--- /dev/null
+/*
+ * Copyright (c) 2003, 2004, 2005, 2006 PathScale, Inc. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses. You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ * 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.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/delay.h>
+#include <linux/pci.h>
+#include <linux/vmalloc.h>
+
+#include "ipath_kernel.h"
+
+/*
+ * InfiniPath I2C driver for a serial eeprom. This is not a generic
+ * I2C interface. For a start, the device we're using (Atmel AT24C11)
+ * doesn't work like a regular I2C device. It looks like one
+ * electrically, but not logically. Normal I2C devices have a single
+ * 7-bit or 10-bit I2C address that they respond to. Valid 7-bit
+ * addresses range from 0x03 to 0x77. Addresses 0x00 to 0x02 and 0x78
+ * to 0x7F are special reserved addresses (e.g. 0x00 is the "general
+ * call" address.) The Atmel device, on the other hand, responds to ALL
+ * 7-bit addresses. It's designed to be the only device on a given I2C
+ * bus. A 7-bit address corresponds to the memory address within the
+ * Atmel device itself.
+ *
+ * Also, the timing requirements mean more than simple software
+ * bitbanging, with readbacks from chip to ensure timing (simple udelay
+ * is not enough).
+ *
+ * This all means that accessing the device is specialized enough
+ * that using the standard kernel I2C bitbanging interface would be
+ * impossible. For example, the core I2C eeprom driver expects to find
+ * a device at one or more of a limited set of addresses only. It doesn't
+ * allow writing to an eeprom. It also doesn't provide any means of
+ * accessing eeprom contents from within the kernel, only via sysfs.
+ */
+
+enum i2c_type {
+ i2c_line_scl = 0,
+ i2c_line_sda
+};
+
+enum i2c_state {
+ i2c_line_low = 0,
+ i2c_line_high
+};
+
+#define READ_CMD 1
+#define WRITE_CMD 0
+
+static int eeprom_init;
+
+/*
+ * The gpioval manipulation really should be protected by spinlocks
+ * or be converted to use atomic operations.
+ */
+
+/**
+ * i2c_gpio_set - set a GPIO line
+ * @dd: the infinipath device
+ * @line: the line to set
+ * @new_line_state: the state to set
+ *
+ * Returns 0 if the line was set to the new state successfully, non-zero
+ * on error.
+ */
+static int i2c_gpio_set(struct ipath_devdata *dd,
+ enum i2c_type line,
+ enum i2c_state new_line_state)
+{
+ u64 read_val, write_val, mask, *gpioval;
+
+ gpioval = &dd->ipath_gpio_out;
+ read_val = ipath_read_kreg64(dd, dd->ipath_kregs->kr_extctrl);
+ if (line == i2c_line_scl)
+ mask = ipath_gpio_scl;
+ else
+ mask = ipath_gpio_sda;
+
+ if (new_line_state == i2c_line_high)
+ /* tri-state the output rather than force high */
+ write_val = read_val & ~mask;
+ else
+ /* config line to be an output */
+ write_val = read_val | mask;
+ ipath_write_kreg(dd, dd->ipath_kregs->kr_extctrl, write_val);
+
+ /* set high and verify */
+ if (new_line_state == i2c_line_high)
+ write_val = 0x1UL;
+ else
+ write_val = 0x0UL;
+
+ if (line == i2c_line_scl) {
+ write_val <<= ipath_gpio_scl_num;
+ *gpioval = *gpioval & ~(1UL << ipath_gpio_scl_num);
+ *gpioval |= write_val;
+ } else {
+ write_val <<= ipath_gpio_sda_num;
+ *gpioval = *gpioval & ~(1UL << ipath_gpio_sda_num);
+ *gpioval |= write_val;
+ }
+ ipath_write_kreg(dd, dd->ipath_kregs->kr_gpio_out, *gpioval);
+
+ return 0;
+}
+
+/**
+ * i2c_gpio_get - get a GPIO line state
+ * @dd: the infinipath device
+ * @line: the line to get
+ * @curr_statep: where to put the line state
+ *
+ * Returns 0 if the line was set to the new state successfully, non-zero
+ * on error. curr_state is not set on error.
+ */
+static int i2c_gpio_get(struct ipath_devdata *dd,
+ enum i2c_type line,
+ enum i2c_state *curr_statep)
+{
+ u64 read_val, write_val, mask;
+ int ret;
+
+ /* check args */
+ if (curr_statep == NULL) {
+ ret = 1;
+ goto bail;
+ }
+
+ read_val = ipath_read_kreg64(dd, dd->ipath_kregs->kr_extctrl);
+ /* config line to be an input */
+ if (line == i2c_line_scl)
+ mask = ipath_gpio_scl;
+ else
+ mask = ipath_gpio_sda;
+ write_val = read_val & ~mask;
+ ipath_write_kreg(dd, dd->ipath_kregs->kr_extctrl, write_val);
+ read_val = ipath_read_kreg64(dd, dd->ipath_kregs->kr_extstatus);
+
+ if (read_val & mask)
+ *curr_statep = i2c_line_high;
+ else
+ *curr_statep = i2c_line_low;
+
+ ret = 0;
+
+bail:
+ return ret;
+}
+
+/**
+ * i2c_wait_for_writes - wait for a write
+ * @dd: the infinipath 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 ipath_devdata *dd)
+{
+ (void)ipath_read_kreg32(dd, dd->ipath_kregs->kr_scratch);
+}
+
+static void scl_out(struct ipath_devdata *dd, u8 bit)
+{
+ i2c_gpio_set(dd, i2c_line_scl, bit ? i2c_line_high : i2c_line_low);
+
+ i2c_wait_for_writes(dd);
+}
+
+static void sda_out(struct ipath_devdata *dd, u8 bit)
+{
+ i2c_gpio_set(dd, i2c_line_sda, bit ? i2c_line_high : i2c_line_low);
+
+ i2c_wait_for_writes(dd);
+}
+
+static u8 sda_in(struct ipath_devdata *dd, int wait)
+{
+ enum i2c_state bit;
+
+ if (i2c_gpio_get(dd, i2c_line_sda, &bit))
+ ipath_dbg("get bit failed!\n");
+
+ if (wait)
+ i2c_wait_for_writes(dd);
+
+ return bit == i2c_line_high ? 1U : 0;
+}
+
+/**
+ * i2c_ackrcv - see if ack following write is true
+ * @dd: the infinipath device
+ */
+static int i2c_ackrcv(struct ipath_devdata *dd)
+{
+ u8 ack_received;
+
+ /* AT ENTRY SCL = LOW */
+ /* change direction, ignore data */
+ ack_received = sda_in(dd, 1);
+ scl_out(dd, i2c_line_high);
+ ack_received = sda_in(dd, 1) == 0;
+ scl_out(dd, i2c_line_low);
+ return ack_received;
+}
+
+/**
+ * wr_byte - write a byte, one bit at a time
+ * @dd: the infinipath device
+ * @data: the byte to write
+ *
+ * Returns 0 if we got the following ack, otherwise 1
+ */
+static int wr_byte(struct ipath_devdata *dd, u8 data)
+{
+ int bit_cntr;
+ u8 bit;
+
+ for (bit_cntr = 7; bit_cntr >= 0; bit_cntr--) {
+ bit = (data >> bit_cntr) & 1;
+ sda_out(dd, bit);
+ scl_out(dd, i2c_line_high);
+ scl_out(dd, i2c_line_low);
+ }
+ return (!i2c_ackrcv(dd)) ? 1 : 0;
+}
+
+static void send_ack(struct ipath_devdata *dd)
+{
+ sda_out(dd, i2c_line_low);
+ scl_out(dd, i2c_line_high);
+ scl_out(dd, i2c_line_low);
+ sda_out(dd, i2c_line_high);
+}
+
+/**
+ * i2c_startcmd - transmit the start condition, followed by address/cmd
+ * @dd: the infinipath device
+ * @offset_dir: direction byte
+ *
+ * (both clock/data high, clock high, data low while clock is high)
+ */
+static int i2c_startcmd(struct ipath_devdata *dd, u8 offset_dir)
+{
+ int res;
+
+ /* issue start sequence */
+ sda_out(dd, i2c_line_high);
+ scl_out(dd, i2c_line_high);
+ sda_out(dd, i2c_line_low);
+ scl_out(dd, i2c_line_low);
+
+ /* issue length and direction byte */
+ res = wr_byte(dd, offset_dir);
+
+ if (res)
+ ipath_cdbg(VERBOSE, "No ack to complete start\n");
+
+ return res;
+}
+
+/**
+ * stop_cmd - transmit the stop condition
+ * @dd: the infinipath device
+ *
+ * (both clock/data low, clock high, data high while clock is high)
+ */
+static void stop_cmd(struct ipath_devdata *dd)
+{
+ scl_out(dd, i2c_line_low);
+ sda_out(dd, i2c_line_low);
+ scl_out(dd, i2c_line_high);
+ sda_out(dd, i2c_line_high);
+ udelay(2);
+}
+
+/**
+ * eeprom_reset - reset I2C communication
+ * @dd: the infinipath device
+ */
+
+static int eeprom_reset(struct ipath_devdata *dd)
+{
+ int clock_cycles_left = 9;
+ u64 *gpioval = &dd->ipath_gpio_out;
+ int ret;
+
+ eeprom_init = 1;
+ *gpioval = ipath_read_kreg64(dd, dd->ipath_kregs->kr_gpio_out);
+ ipath_cdbg(VERBOSE, "Resetting i2c eeprom; initial gpioout reg "
+ "is %llx\n", (unsigned long long) *gpioval);
+
+ /*
+ * This is to get the i2c into a known state, by first going low,
+ * then tristate sda (and then tristate scl as first thing
+ * in loop)
+ */
+ scl_out(dd, i2c_line_low);
+ sda_out(dd, i2c_line_high);
+
+ while (clock_cycles_left--) {
+ scl_out(dd, i2c_line_high);
+
+ if (sda_in(dd, 0)) {
+ sda_out(dd, i2c_line_low);
+ scl_out(dd, i2c_line_low);
+ ret = 0;
+ goto bail;
+ }
+
+ scl_out(dd, i2c_line_low);
+ }
+
+ ret = 1;
+
+bail:
+ return ret;
+}
+
+/**
+ * ipath_eeprom_read - receives bytes from the eeprom via I2C
+ * @dd: the infinipath device
+ * @eeprom_offset: address to read from
+ * @buffer: where to store result
+ * @len: number of bytes to receive
+ */
+
+int ipath_eeprom_read(struct ipath_devdata *dd, u8 eeprom_offset,
+ void *buffer, int len)
+{
+ /* compiler complains unless initialized */
+ u8 single_byte = 0;
+ int bit_cntr;
+ int ret;
+
+ if (!eeprom_init)
+ eeprom_reset(dd);
+
+ eeprom_offset = (eeprom_offset << 1) | READ_CMD;
+
+ if (i2c_startcmd(dd, eeprom_offset)) {
+ ipath_dbg("Failed startcmd\n");
+ stop_cmd(dd);
+ ret = 1;
+ goto bail;
+ }
+
+ /*
+ * eeprom keeps clocking data out as long as we ack, automatically
+ * incrementing the address.
+ */
+ while (len-- > 0) {
+ /* get data */
+ single_byte = 0;
+ for (bit_cntr = 8; bit_cntr; bit_cntr--) {
+ u8 bit;
+ scl_out(dd, i2c_line_high);
+ bit = sda_in(dd, 0);
+ single_byte |= bit << (bit_cntr - 1);
+ scl_out(dd, i2c_line_low);
+ }
+
+ /* send ack if not the last byte */
+ if (len)
+ send_ack(dd);
+
+ *((u8 *) buffer) = single_byte;
+ buffer++;
+ }
+
+ stop_cmd(dd);
+
+ ret = 0;
+
+bail:
+ return ret;
+}
+
+/**
+ * ipath_eeprom_write - writes data to the eeprom via I2C
+ * @dd: the infinipath device
+ * @eeprom_offset: where to place data
+ * @buffer: data to write
+ * @len: number of bytes to write
+ */
+int ipath_eeprom_write(struct ipath_devdata *dd, u8 eeprom_offset,
+ const void *buffer, int len)
+{
+ u8 single_byte;
+ int sub_len;
+ const u8 *bp = buffer;
+ int max_wait_time, i;
+ int ret;
+
+ if (!eeprom_init)
+ eeprom_reset(dd);
+
+ while (len > 0) {
+ if (i2c_startcmd(dd, (eeprom_offset << 1) | WRITE_CMD)) {
+ ipath_dbg("Failed to start cmd offset %u\n",
+ eeprom_offset);
+ goto failed_write;
+ }
+
+ sub_len = min(len, 4);
+ eeprom_offset += sub_len;
+ len -= sub_len;
+
+ for (i = 0; i < sub_len; i++) {
+ if (wr_byte(dd, *bp++)) {
+ ipath_dbg("no ack after byte %u/%u (%u "
+ "total remain)\n", i, sub_len,
+ len + sub_len - i);
+ goto failed_write;
+ }
+ }
+
+ stop_cmd(dd);
+
+ /*
+ * wait for write complete by waiting for a successful
+ * read (the chip replies with a zero after the write
+ * cmd completes, and before it writes to the eeprom.
+ * The startcmd for the read will fail the ack until
+ * the writes have completed. We do this inline to avoid
+ * the debug prints that are in the real read routine
+ * if the startcmd fails.
+ */
+ max_wait_time = 100;
+ while (i2c_startcmd(dd, READ_CMD)) {
+ stop_cmd(dd);
+ if (!--max_wait_time) {
+ ipath_dbg("Did not get successful read to "
+ "complete write\n");
+ goto failed_write;
+ }
+ }
+ /* now read the zero byte */
+ for (i = single_byte = 0; i < 8; i++) {
+ u8 bit;
+ scl_out(dd, i2c_line_high);
+ bit = sda_in(dd, 0);
+ scl_out(dd, i2c_line_low);
+ single_byte <<= 1;
+ single_byte |= bit;
+ }
+ stop_cmd(dd);
+ }
+
+ ret = 0;
+ goto bail;
+
+failed_write:
+ stop_cmd(dd);
+ ret = 1;
+
+bail:
+ return ret;
+}
+
+static u8 flash_csum(struct ipath_flash *ifp, int adjust)
+{
+ u8 *ip = (u8 *) ifp;
+ u8 csum = 0, len;
+
+ for (len = 0; len < ifp->if_length; len++)
+ csum += *ip++;
+ csum -= ifp->if_csum;
+ csum = ~csum;
+ if (adjust)
+ ifp->if_csum = csum;
+
+ return csum;
+}
+
+/**
+ * ipath_get_guid - get the GUID from the i2c device
+ * @dd: the infinipath device
+ *
+ * We have the capability to use the ipath_nguid field, and get
+ * the guid from the first chip's flash, to use for all of them.
+ */
+void ipath_get_eeprom_info(struct ipath_devdata *dd)
+{
+ void *buf;
+ struct ipath_flash *ifp;
+ __be64 guid;
+ int len;
+ u8 csum, *bguid;
+ int t = dd->ipath_unit;
+ struct ipath_devdata *dd0 = ipath_lookup(0);
+
+ if (t && dd0->ipath_nguid > 1 && t <= dd0->ipath_nguid) {
+ u8 *bguid, oguid;
+ dd->ipath_guid = dd0->ipath_guid;
+ bguid = (u8 *) & dd->ipath_guid;
+
+ oguid = bguid[7];
+ bguid[7] += t;
+ if (oguid > bguid[7]) {
+ if (bguid[6] == 0xff) {
+ if (bguid[5] == 0xff) {
+ ipath_dev_err(
+ dd,
+ "Can't set %s GUID from "
+ "base, wraps to OUI!\n",
+ ipath_get_unit_name(t));
+ dd->ipath_guid = 0;
+ goto bail;
+ }
+ bguid[5]++;
+ }
+ bguid[6]++;
+ }
+ dd->ipath_nguid = 1;
+
+ ipath_dbg("nguid %u, so adding %u to device 0 guid, "
+ "for %llx\n",
+ dd0->ipath_nguid, t,
+ (unsigned long long) be64_to_cpu(dd->ipath_guid));
+ goto bail;
+ }
+
+ len = offsetof(struct ipath_flash, if_future);
+ buf = vmalloc(len);
+ if (!buf) {
+ ipath_dev_err(dd, "Couldn't allocate memory to read %u "
+ "bytes from eeprom for GUID\n", len);
+ goto bail;
+ }
+
+ if (ipath_eeprom_read(dd, 0, buf, len)) {
+ ipath_dev_err(dd, "Failed reading GUID from eeprom\n");
+ goto done;
+ }
+ ifp = (struct ipath_flash *)buf;
+
+ csum = flash_csum(ifp, 0);
+ if (csum != ifp->if_csum) {
+ dev_info(&dd->pcidev->dev, "Bad I2C flash checksum: "
+ "0x%x, not 0x%x\n", csum, ifp->if_csum);
+ goto done;
+ }
+ if (*(__be64 *) ifp->if_guid == 0ULL ||
+ *(__be64 *) ifp->if_guid == __constant_cpu_to_be64(-1LL)) {
+ ipath_dev_err(dd, "Invalid GUID %llx from flash; "
+ "ignoring\n",
+ *(unsigned long long *) ifp->if_guid);
+ /* don't allow GUID if all 0 or all 1's */
+ goto done;
+ }
+
+ /* complain, but allow it */
+ if (*(u64 *) ifp->if_guid == 0x100007511000000ULL)
+ dev_info(&dd->pcidev->dev, "Warning, GUID %llx is "
+ "default, probably not correct!\n",
+ *(unsigned long long *) ifp->if_guid);
+
+ bguid = ifp->if_guid;
+ if (!bguid[0] && !bguid[1] && !bguid[2]) {
+ /* original incorrect GUID format in flash; fix in
+ * core copy, by shifting up 2 octets; don't need to
+ * change top octet, since both it and shifted are
+ * 0.. */
+ bguid[1] = bguid[3];
+ bguid[2] = bguid[4];
+ bguid[3] = bguid[4] = 0;
+ guid = *(__be64 *) ifp->if_guid;
+ ipath_cdbg(VERBOSE, "Old GUID format in flash, top 3 zero, "
+ "shifting 2 octets\n");
+ } else
+ guid = *(__be64 *) ifp->if_guid;
+ dd->ipath_guid = guid;
+ dd->ipath_nguid = ifp->if_numguid;
+ memcpy(dd->ipath_serial, ifp->if_serial,
+ sizeof(ifp->if_serial));
+ ipath_cdbg(VERBOSE, "Initted GUID to %llx from eeprom\n",
+ (unsigned long long) be64_to_cpu(dd->ipath_guid));
+
+done:
+ vfree(buf);
+
+bail:;
+}
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