[PATCH 05/13] platform/chrome: cros_ec_lpc: Add R/W helpers to LPC protocol variants

From: Enric Balletbo i Serra
Date: Fri Mar 17 2017 - 09:59:51 EST

From: Shawn Nematbakhsh <shawnn@xxxxxxxxxxxx>

Call common functions for read / write to prepare support for future
LPC protocol variants which use different I/O ops than inb / outb.

Signed-off-by: Shawn Nematbakhsh <shawnn@xxxxxxxxxxxx>
Signed-off-by: Thierry Escande <thierry.escande@xxxxxxxxxxxxx>
---
Changelog:
- v2:
-Fixed coding style issues
-Updated copyright to year 2016

drivers/platform/chrome/Makefile | 3 +-
drivers/platform/chrome/cros_ec_lpc.c | 88 +++++++++++++------------------
drivers/platform/chrome/cros_ec_lpc_reg.c | 64 ++++++++++++++++++++++
include/linux/mfd/cros_ec_lpc_reg.h | 47 +++++++++++++++++
4 files changed, 151 insertions(+), 51 deletions(-)
create mode 100644 drivers/platform/chrome/cros_ec_lpc_reg.c
create mode 100644 include/linux/mfd/cros_ec_lpc_reg.h

diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index 3870afe..61182fd 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -5,6 +5,7 @@ cros_ec_devs-objs := cros_ec_dev.o cros_ec_sysfs.o \
cros_ec_lightbar.o cros_ec_vbc.o \
cros_ec_debugfs.o
obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_devs.o
-obj-$(CONFIG_CROS_EC_LPC) += cros_ec_lpc.o
+cros_ec_lpcs-objs := cros_ec_lpc.o cros_ec_lpc_reg.o
+obj-$(CONFIG_CROS_EC_LPC) += cros_ec_lpcs.o
obj-$(CONFIG_CROS_EC_PROTO) += cros_ec_proto.o
obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT) += cros_kbd_led_backlight.o
diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
index f9a2454..6a782a6 100644
--- a/drivers/platform/chrome/cros_ec_lpc.c
+++ b/drivers/platform/chrome/cros_ec_lpc.c
@@ -26,19 +26,22 @@
#include <linux/io.h>
#include <linux/mfd/cros_ec.h>
#include <linux/mfd/cros_ec_commands.h>
+#include <linux/mfd/cros_ec_lpc_reg.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/printk.h>

-#define DRV_NAME "cros_ec_lpc"
+#define DRV_NAME "cros_ec_lpcs"

static int ec_response_timed_out(void)
{
unsigned long one_second = jiffies + HZ;
+ u8 data;

usleep_range(200, 300);
do {
- if (!(inb(EC_LPC_ADDR_HOST_CMD) & EC_LPC_STATUS_BUSY_MASK))
+ if (!(cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_CMD, 1, &data) &
+ EC_LPC_STATUS_BUSY_MASK))
return 0;
usleep_range(100, 200);
} while (time_before(jiffies, one_second));
@@ -51,21 +54,20 @@ static int cros_ec_pkt_xfer_lpc(struct cros_ec_device *ec,
{
struct ec_host_request *request;
struct ec_host_response response;
- u8 sum = 0;
- int i;
+ u8 sum;
int ret = 0;
u8 *dout;

ret = cros_ec_prepare_tx(ec, msg);

/* Write buffer */
- for (i = 0; i < ret; i++)
- outb(ec->dout[i], EC_LPC_ADDR_HOST_PACKET + i);
+ cros_ec_lpc_write_bytes(EC_LPC_ADDR_HOST_PACKET, ret, ec->dout);

request = (struct ec_host_request *)ec->dout;

/* Here we go */
- outb(EC_COMMAND_PROTOCOL_3, EC_LPC_ADDR_HOST_CMD);
+ sum = EC_COMMAND_PROTOCOL_3;
+ cros_ec_lpc_write_bytes(EC_LPC_ADDR_HOST_CMD, 1, &sum);

if (ec_response_timed_out()) {
dev_warn(ec->dev, "EC responsed timed out\n");
@@ -74,17 +76,15 @@ static int cros_ec_pkt_xfer_lpc(struct cros_ec_device *ec,
}

/* Check result */
- msg->result = inb(EC_LPC_ADDR_HOST_DATA);
+ msg->result = cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_DATA, 1, &sum);
ret = cros_ec_check_result(ec, msg);
if (ret)
goto done;

/* Read back response */
dout = (u8 *)&response;
- for (i = 0; i < sizeof(response); i++) {
- dout[i] = inb(EC_LPC_ADDR_HOST_PACKET + i);
- sum += dout[i];
- }
+ sum = cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_PACKET, sizeof(response),
+ dout);

msg->result = response.result;

@@ -97,11 +97,9 @@ static int cros_ec_pkt_xfer_lpc(struct cros_ec_device *ec,
}

/* Read response and process checksum */
- for (i = 0; i < response.data_len; i++) {
- msg->data[i] =
- inb(EC_LPC_ADDR_HOST_PACKET + sizeof(response) + i);
- sum += msg->data[i];
- }
+ sum += cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_PACKET +
+ sizeof(response), response.data_len,
+ msg->data);

if (sum) {
dev_err(ec->dev,
@@ -121,8 +119,7 @@ static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec,
struct cros_ec_command *msg)
{
struct ec_lpc_host_args args;
- int csum;
- int i;
+ u8 sum;
int ret = 0;

if (msg->outsize > EC_PROTO2_MAX_PARAM_SIZE ||
@@ -139,24 +136,20 @@ static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec,
args.data_size = msg->outsize;

/* Initialize checksum */
- csum = msg->command + args.flags +
- args.command_version + args.data_size;
+ sum = msg->command + args.flags + args.command_version + args.data_size;

/* Copy data and update checksum */
- for (i = 0; i < msg->outsize; i++) {
- outb(msg->data[i], EC_LPC_ADDR_HOST_PARAM + i);
- csum += msg->data[i];
- }
+ sum += cros_ec_lpc_write_bytes(EC_LPC_ADDR_HOST_PARAM, msg->outsize,
+ msg->data);

/* Finalize checksum and write args */
- args.checksum = csum & 0xFF;
- outb(args.flags, EC_LPC_ADDR_HOST_ARGS);
- outb(args.command_version, EC_LPC_ADDR_HOST_ARGS + 1);
- outb(args.data_size, EC_LPC_ADDR_HOST_ARGS + 2);
- outb(args.checksum, EC_LPC_ADDR_HOST_ARGS + 3);
+ args.checksum = sum;
+ cros_ec_lpc_write_bytes(EC_LPC_ADDR_HOST_ARGS, sizeof(args),
+ (u8 *)&args);

/* Here we go */
- outb(msg->command, EC_LPC_ADDR_HOST_CMD);
+ sum = msg->command;
+ cros_ec_lpc_write_bytes(EC_LPC_ADDR_HOST_CMD, 1, &sum);

if (ec_response_timed_out()) {
dev_warn(ec->dev, "EC responsed timed out\n");
@@ -165,16 +158,14 @@ static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec,
}

/* Check result */
- msg->result = inb(EC_LPC_ADDR_HOST_DATA);
+ msg->result = cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_DATA, 1, &sum);
ret = cros_ec_check_result(ec, msg);
if (ret)
goto done;

/* Read back args */
- args.flags = inb(EC_LPC_ADDR_HOST_ARGS);
- args.command_version = inb(EC_LPC_ADDR_HOST_ARGS + 1);
- args.data_size = inb(EC_LPC_ADDR_HOST_ARGS + 2);
- args.checksum = inb(EC_LPC_ADDR_HOST_ARGS + 3);
+ cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_ARGS, sizeof(args),
+ (u8 *)&args);

if (args.data_size > msg->insize) {
dev_err(ec->dev,
@@ -185,20 +176,17 @@ static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec,
}

/* Start calculating response checksum */
- csum = msg->command + args.flags +
- args.command_version + args.data_size;
+ sum = msg->command + args.flags + args.command_version + args.data_size;

/* Read response and update checksum */
- for (i = 0; i < args.data_size; i++) {
- msg->data[i] = inb(EC_LPC_ADDR_HOST_PARAM + i);
- csum += msg->data[i];
- }
+ sum += cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_PARAM, args.data_size,
+ msg->data);

/* Verify checksum */
- if (args.checksum != (csum & 0xFF)) {
+ if (args.checksum != sum) {
dev_err(ec->dev,
"bad packet checksum, expected %02x, got %02x\n",
- args.checksum, csum & 0xFF);
+ args.checksum, sum);
ret = -EBADMSG;
goto done;
}
@@ -222,14 +210,13 @@ static int cros_ec_lpc_readmem(struct cros_ec_device *ec, unsigned int offset,

/* fixed length */
if (bytes) {
- for (; cnt < bytes; i++, s++, cnt++)
- *s = inb(EC_LPC_ADDR_MEMMAP + i);
- return cnt;
+ cros_ec_lpc_read_bytes(EC_LPC_ADDR_MEMMAP + offset, bytes, s);
+ return bytes;
}

/* string */
for (; i < EC_MEMMAP_SIZE; i++, s++) {
- *s = inb(EC_LPC_ADDR_MEMMAP + i);
+ cros_ec_lpc_read_bytes(EC_LPC_ADDR_MEMMAP + i, 1, s);
cnt++;
if (!*s)
break;
@@ -242,6 +229,7 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct cros_ec_device *ec_dev;
+ u8 buf[2];
int ret;

if (!devm_request_region(dev, EC_LPC_ADDR_MEMMAP, EC_MEMMAP_SIZE,
@@ -250,8 +238,8 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
return -EBUSY;
}

- if ((inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID) != 'E') ||
- (inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID + 1) != 'C')) {
+ cros_ec_lpc_read_bytes(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID, 2, buf);
+ if (buf[0] != 'E' || buf[1] != 'C') {
dev_err(dev, "EC ID not detected\n");
return -ENODEV;
}
diff --git a/drivers/platform/chrome/cros_ec_lpc_reg.c b/drivers/platform/chrome/cros_ec_lpc_reg.c
new file mode 100644
index 0000000..03c9781
--- /dev/null
+++ b/drivers/platform/chrome/cros_ec_lpc_reg.c
@@ -0,0 +1,64 @@
+/*
+ * cros_ec_lpc_reg - LPC access to the Chrome OS Embedded Controller
+ *
+ * Copyright (C) 2016 Google, Inc
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ * This driver uses the Chrome OS EC byte-level message-based protocol for
+ * communicating the keyboard state (which keys are pressed) from a keyboard EC
+ * to the AP over some bus (such as i2c, lpc, spi). The EC does debouncing,
+ * but everything else (including deghosting) is done here. The main
+ * motivation for this is to keep the EC firmware as simple as possible, since
+ * it cannot be easily upgraded and EC flash/IRAM space is relatively
+ * expensive.
+ */
+
+#include <linux/io.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/mfd/cros_ec_commands.h>
+
+static u8 lpc_read_bytes(unsigned int offset, unsigned int length, u8 *dest)
+{
+ int i;
+ int sum = 0;
+
+ for (i = 0; i < length; ++i) {
+ dest[i] = inb(offset + i);
+ sum += dest[i];
+ }
+
+ /* Return checksum of all bytes read */
+ return sum;
+}
+
+static u8 lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg)
+{
+ int i;
+ int sum = 0;
+
+ for (i = 0; i < length; ++i) {
+ outb(msg[i], offset + i);
+ sum += msg[i];
+ }
+
+ /* Return checksum of all bytes written */
+ return sum;
+}
+
+u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length, u8 *dest)
+{
+ return lpc_read_bytes(offset, length, dest);
+}
+
+u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg)
+{
+ return lpc_write_bytes(offset, length, msg);
+}
diff --git a/include/linux/mfd/cros_ec_lpc_reg.h b/include/linux/mfd/cros_ec_lpc_reg.h
new file mode 100644
index 0000000..4089bd5
--- /dev/null
+++ b/include/linux/mfd/cros_ec_lpc_reg.h
@@ -0,0 +1,47 @@
+/*
+ * cros_ec_lpc_reg - LPC access to the Chrome OS Embedded Controller
+ *
+ * Copyright (C) 2016 Google, Inc
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ * This driver uses the Chrome OS EC byte-level message-based protocol for
+ * communicating the keyboard state (which keys are pressed) from a keyboard EC
+ * to the AP over some bus (such as i2c, lpc, spi). The EC does debouncing,
+ * but everything else (including deghosting) is done here. The main
+ * motivation for this is to keep the EC firmware as simple as possible, since
+ * it cannot be easily upgraded and EC flash/IRAM space is relatively
+ * expensive.
+ */
+
+#ifndef __LINUX_MFD_CROS_EC_REG_H
+#define __LINUX_MFD_CROS_EC_REG_H
+
+/**
+ * cros_ec_lpc_read_bytes - Read bytes from a given LPC-mapped address.
+ * Returns 8-bit checksum of all bytes read.
+ *
+ * @offset: Base read address
+ * @length: Number of bytes to read
+ * @dest: Destination buffer
+ */
+u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length, u8 *dest);
+
+/**
+ * cros_ec_lpc_write_bytes - Write bytes to a given LPC-mapped address.
+ * Returns 8-bit checksum of all bytes written.
+ *
+ * @offset: Base write address
+ * @length: Number of bytes to write
+ * @msg: Write data buffer
+ */
+u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg);
+
+#endif /* __LINUX_MFD_CROS_EC_REG_H */
--
2.9.3