IB/ipath: misc driver support code

EEPROM support, interrupt handling, statistics gathering, and write
combining management for x86_64.

A note regarding i2c: The Atmel EEPROM hardware we use looks like an
i2c device electrically, but is not i2c compliant at all from a
functional perspective.  We tried using the kernel's i2c support to
talk to it, but failed.

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 addresses.  It's designed to be the only
device on a given i2c bus.  A given i2c device address corresponds to
the memory address within the i2c device itself.

At least one reason why the linux core i2c stuff won't work for this
is that it prohibits access to reserved addresses like 0x00, which are
really valid addresses on the Atmel devices.

Signed-off-by: Bryan O'Sullivan <bos@pathscale.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 613 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_eeprom.c b/drivers/infiniband/hw/ipath/ipath_eeprom.c
new file mode 100644
index 00000000000..f11a900e8cd
--- /dev/null
+++ b/drivers/infiniband/hw/ipath/ipath_eeprom.c
@@ -0,0 +1,613 @@
+/*
+ * 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
+ *
+ * When we add the multi-chip support, we will probably have to add
+ * the ability to use the number of guids field, and get the guid from
+ * the first chip's flash, to use for all of them.
+ */
+void ipath_get_guid(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:;
+}