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SubjectRe: [PATCH 05/13] platform/chrome: cros_ec_lpc: Add R/W helpers to LPC protocol variants
On Fri, 17 Mar 2017, Enric Balletbo i Serra wrote:

> From: Shawn Nematbakhsh <shawnn@chromium.org>
>
> 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@chromium.org>
> Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
> ---
> 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 +++++++++++++++++

Acked-by: Lee Jones <lee.jones@linaro.org>

> 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 */

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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