drivers/platform/chrome/cros_ec_lpc.c - kernel/mindspeed - Git at Google

 /*
  * cros_ec_lpc - LPC access to the Chrome OS Embedded Controller
  *
  * Copyright (C) 2012-2015 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/dmi.h>
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/mfd/cros_ec.h>
 #include <linux/mfd/cros_ec_commands.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/printk.h>

 #define DRV_NAME "cros_ec_lpc"

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

 	usleep_range(200, 300);
 	do {
 		if (!(inb(EC_LPC_ADDR_HOST_CMD) & EC_LPC_STATUS_BUSY_MASK))
 			return 0;
 		usleep_range(100, 200);
 	} while (time_before(jiffies, one_second));

 	return 1;
 }

 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;
 	int ret = 0;

 	if (msg->outsize > EC_PROTO2_MAX_PARAM_SIZE ||
 	    msg->insize > EC_PROTO2_MAX_PARAM_SIZE) {
 		dev_err(ec->dev,
 			"invalid buffer sizes (out %d, in %d)\n",
 			msg->outsize, msg->insize);
 		return -EINVAL;
 	}

 	/* Now actually send the command to the EC and get the result */
 	args.flags = EC_HOST_ARGS_FLAG_FROM_HOST;
 	args.command_version = msg->version;
 	args.data_size = msg->outsize;

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

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

 	/* 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);

 	/* Here we go */
 	outb(msg->command, EC_LPC_ADDR_HOST_CMD);

 	if (ec_response_timed_out()) {
 		dev_warn(ec->dev, "EC responsed timed out\n");
 		ret = -EIO;
 		goto done;
 	}

 	/* Check result */
 	msg->result = inb(EC_LPC_ADDR_HOST_DATA);

 	switch (msg->result) {
 	case EC_RES_SUCCESS:
 		break;
 	case EC_RES_IN_PROGRESS:
 		ret = -EAGAIN;
 		dev_dbg(ec->dev, "command 0x%02x in progress\n",
 			msg->command);
 		goto done;
 	default:
 		dev_dbg(ec->dev, "command 0x%02x returned %d\n",
 			msg->command, msg->result);
 	}

 	/* 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);

 	if (args.data_size > msg->insize) {
 		dev_err(ec->dev,
 			"packet too long (%d bytes, expected %d)",
 			args.data_size, msg->insize);
 		ret = -ENOSPC;
 		goto done;
 	}

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

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

 	/* Verify checksum */
 	if (args.checksum != (csum & 0xFF)) {
 		dev_err(ec->dev,
 			"bad packet checksum, expected %02x, got %02x\n",
 			args.checksum, csum & 0xFF);
 		ret = -EBADMSG;
 		goto done;
 	}

 	/* Return actual amount of data received */
 	ret = args.data_size;
 done:
 	return ret;
 }

 /* Returns num bytes read, or negative on error. Doesn't need locking. */
 static int cros_ec_lpc_readmem(struct cros_ec_device *ec, unsigned int offset,
 			       unsigned int bytes, void *dest)
 {
 	int i = offset;
 	char *s = dest;
 	int cnt = 0;

 	if (offset >= EC_MEMMAP_SIZE - bytes)
 		return -EINVAL;

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

 	/* string */
 	for (; i < EC_MEMMAP_SIZE; i++, s++) {
 		*s = inb(EC_LPC_ADDR_MEMMAP + i);
 		cnt++;
 		if (!*s)
 			break;
 	}

 	return cnt;
 }

 static int cros_ec_lpc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct cros_ec_device *ec_dev;
 	int ret;

 	if (!devm_request_region(dev, EC_LPC_ADDR_MEMMAP, EC_MEMMAP_SIZE,
 				 dev_name(dev))) {
 		dev_err(dev, "couldn't reserve memmap region\n");
 		return -EBUSY;
 	}

 	if ((inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID) != 'E') ||
 	    (inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID + 1) != 'C')) {
 		dev_err(dev, "EC ID not detected\n");
 		return -ENODEV;
 	}

 	if (!devm_request_region(dev, EC_HOST_CMD_REGION0,
 				 EC_HOST_CMD_REGION_SIZE, dev_name(dev))) {
 		dev_err(dev, "couldn't reserve region0\n");
 		return -EBUSY;
 	}
 	if (!devm_request_region(dev, EC_HOST_CMD_REGION1,
 				 EC_HOST_CMD_REGION_SIZE, dev_name(dev))) {
 		dev_err(dev, "couldn't reserve region1\n");
 		return -EBUSY;
 	}

 	ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
 	if (!ec_dev)
 		return -ENOMEM;

 	platform_set_drvdata(pdev, ec_dev);
 	ec_dev->dev = dev;
 	ec_dev->ec_name = pdev->name;
 	ec_dev->phys_name = dev_name(dev);
 	ec_dev->parent = dev;
 	ec_dev->cmd_xfer = cros_ec_cmd_xfer_lpc;
 	ec_dev->cmd_readmem = cros_ec_lpc_readmem;

 	ret = cros_ec_register(ec_dev);
 	if (ret) {
 		dev_err(dev, "couldn't register ec_dev (%d)\n", ret);
 		return ret;
 	}

 	return 0;
 }

 static int cros_ec_lpc_remove(struct platform_device *pdev)
 {
 	struct cros_ec_device *ec_dev;

 	ec_dev = platform_get_drvdata(pdev);
 	cros_ec_remove(ec_dev);

 	return 0;
 }

 static struct dmi_system_id cros_ec_lpc_dmi_table[] __initdata = {
 	{
 		/*
 		 * Today all Chromebooks/boxes ship with Google_* as version and
 		 * coreboot as bios vendor. No other systems with this
 		 * combination are known to date.
 		 */
 		.matches = {
 			DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
 			DMI_MATCH(DMI_BIOS_VERSION, "Google_"),
 		},
 	},
 	{
 		/* x86-link, the Chromebook Pixel. */
 		.matches = {
 			DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"),
 			DMI_MATCH(DMI_PRODUCT_NAME, "Link"),
 		},
 	},
 	{
 		/* x86-peppy, the Acer C720 Chromebook. */
 		.matches = {
 			DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 			DMI_MATCH(DMI_PRODUCT_NAME, "Peppy"),
 		},
 	},
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(dmi, cros_ec_lpc_dmi_table);

 static struct platform_driver cros_ec_lpc_driver = {
 	.driver = {
 		.name = DRV_NAME,
 	},
 	.probe = cros_ec_lpc_probe,
 	.remove = cros_ec_lpc_remove,
 };

 static struct platform_device cros_ec_lpc_device = {
 	.name = DRV_NAME
 };

 static int __init cros_ec_lpc_init(void)
 {
 	int ret;

 	if (!dmi_check_system(cros_ec_lpc_dmi_table)) {
 		pr_err(DRV_NAME ": unsupported system.\n");
 		return -ENODEV;
 	}

 	/* Register the driver */
 	ret = platform_driver_register(&cros_ec_lpc_driver);
 	if (ret) {
 		pr_err(DRV_NAME ": can't register driver: %d\n", ret);
 		return ret;
 	}

 	/* Register the device, and it'll get hooked up automatically */
 	ret = platform_device_register(&cros_ec_lpc_device);
 	if (ret) {
 		pr_err(DRV_NAME ": can't register device: %d\n", ret);
 		platform_driver_unregister(&cros_ec_lpc_driver);
 		return ret;
 	}

 	return 0;
 }

 static void __exit cros_ec_lpc_exit(void)
 {
 	platform_device_unregister(&cros_ec_lpc_device);
 	platform_driver_unregister(&cros_ec_lpc_driver);
 }

 module_init(cros_ec_lpc_init);
 module_exit(cros_ec_lpc_exit);

 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("ChromeOS EC LPC driver");
	/*
	* cros_ec_lpc - LPC access to the Chrome OS Embedded Controller
	*
	* Copyright (C) 2012-2015 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/dmi.h>
	#include <linux/delay.h>
	#include <linux/io.h>
	#include <linux/mfd/cros_ec.h>
	#include <linux/mfd/cros_ec_commands.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/printk.h>

	#define DRV_NAME "cros_ec_lpc"

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

	usleep_range(200, 300);
	do {
	if (!(inb(EC_LPC_ADDR_HOST_CMD) & EC_LPC_STATUS_BUSY_MASK))
	return 0;
	usleep_range(100, 200);
	} while (time_before(jiffies, one_second));

	return 1;
	}

	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;
	int ret = 0;

	if (msg->outsize > EC_PROTO2_MAX_PARAM_SIZE \|\|
	msg->insize > EC_PROTO2_MAX_PARAM_SIZE) {
	dev_err(ec->dev,
	"invalid buffer sizes (out %d, in %d)\n",
	msg->outsize, msg->insize);
	return -EINVAL;
	}

	/* Now actually send the command to the EC and get the result */
	args.flags = EC_HOST_ARGS_FLAG_FROM_HOST;
	args.command_version = msg->version;
	args.data_size = msg->outsize;

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

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

	/* 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);

	/* Here we go */
	outb(msg->command, EC_LPC_ADDR_HOST_CMD);

	if (ec_response_timed_out()) {
	dev_warn(ec->dev, "EC responsed timed out\n");
	ret = -EIO;
	goto done;
	}

	/* Check result */
	msg->result = inb(EC_LPC_ADDR_HOST_DATA);

	switch (msg->result) {
	case EC_RES_SUCCESS:
	break;
	case EC_RES_IN_PROGRESS:
	ret = -EAGAIN;
	dev_dbg(ec->dev, "command 0x%02x in progress\n",
	msg->command);
	goto done;
	default:
	dev_dbg(ec->dev, "command 0x%02x returned %d\n",
	msg->command, msg->result);
	}

	/* 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);

	if (args.data_size > msg->insize) {
	dev_err(ec->dev,
	"packet too long (%d bytes, expected %d)",
	args.data_size, msg->insize);
	ret = -ENOSPC;
	goto done;
	}

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

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

	/* Verify checksum */
	if (args.checksum != (csum & 0xFF)) {
	dev_err(ec->dev,
	"bad packet checksum, expected %02x, got %02x\n",
	args.checksum, csum & 0xFF);
	ret = -EBADMSG;
	goto done;
	}

	/* Return actual amount of data received */
	ret = args.data_size;
	done:
	return ret;
	}

	/* Returns num bytes read, or negative on error. Doesn't need locking. */
	static int cros_ec_lpc_readmem(struct cros_ec_device *ec, unsigned int offset,
	unsigned int bytes, void *dest)
	{
	int i = offset;
	char *s = dest;
	int cnt = 0;

	if (offset >= EC_MEMMAP_SIZE - bytes)
	return -EINVAL;

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

	/* string */
	for (; i < EC_MEMMAP_SIZE; i++, s++) {
	*s = inb(EC_LPC_ADDR_MEMMAP + i);
	cnt++;
	if (!*s)
	break;
	}

	return cnt;
	}

	static int cros_ec_lpc_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct cros_ec_device *ec_dev;
	int ret;

	if (!devm_request_region(dev, EC_LPC_ADDR_MEMMAP, EC_MEMMAP_SIZE,
	dev_name(dev))) {
	dev_err(dev, "couldn't reserve memmap region\n");
	return -EBUSY;
	}

	if ((inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID) != 'E') \|\|
	(inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID + 1) != 'C')) {
	dev_err(dev, "EC ID not detected\n");
	return -ENODEV;
	}

	if (!devm_request_region(dev, EC_HOST_CMD_REGION0,
	EC_HOST_CMD_REGION_SIZE, dev_name(dev))) {
	dev_err(dev, "couldn't reserve region0\n");
	return -EBUSY;
	}
	if (!devm_request_region(dev, EC_HOST_CMD_REGION1,
	EC_HOST_CMD_REGION_SIZE, dev_name(dev))) {
	dev_err(dev, "couldn't reserve region1\n");
	return -EBUSY;
	}

	ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
	if (!ec_dev)
	return -ENOMEM;

	platform_set_drvdata(pdev, ec_dev);
	ec_dev->dev = dev;
	ec_dev->ec_name = pdev->name;
	ec_dev->phys_name = dev_name(dev);
	ec_dev->parent = dev;
	ec_dev->cmd_xfer = cros_ec_cmd_xfer_lpc;
	ec_dev->cmd_readmem = cros_ec_lpc_readmem;

	ret = cros_ec_register(ec_dev);
	if (ret) {
	dev_err(dev, "couldn't register ec_dev (%d)\n", ret);
	return ret;
	}

	return 0;
	}

	static int cros_ec_lpc_remove(struct platform_device *pdev)
	{
	struct cros_ec_device *ec_dev;

	ec_dev = platform_get_drvdata(pdev);
	cros_ec_remove(ec_dev);

	return 0;
	}

	static struct dmi_system_id cros_ec_lpc_dmi_table[] __initdata = {
	{
	/*
	* Today all Chromebooks/boxes ship with Google_* as version and
	* coreboot as bios vendor. No other systems with this
	* combination are known to date.
	*/
	.matches = {
	DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
	DMI_MATCH(DMI_BIOS_VERSION, "Google_"),
	},
	},
	{
	/* x86-link, the Chromebook Pixel. */
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"),
	DMI_MATCH(DMI_PRODUCT_NAME, "Link"),
	},
	},
	{
	/* x86-peppy, the Acer C720 Chromebook. */
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
	DMI_MATCH(DMI_PRODUCT_NAME, "Peppy"),
	},
	},
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(dmi, cros_ec_lpc_dmi_table);

	static struct platform_driver cros_ec_lpc_driver = {
	.driver = {
	.name = DRV_NAME,
	},
	.probe = cros_ec_lpc_probe,
	.remove = cros_ec_lpc_remove,
	};

	static struct platform_device cros_ec_lpc_device = {
	.name = DRV_NAME
	};

	static int __init cros_ec_lpc_init(void)
	{
	int ret;

	if (!dmi_check_system(cros_ec_lpc_dmi_table)) {
	pr_err(DRV_NAME ": unsupported system.\n");
	return -ENODEV;
	}

	/* Register the driver */
	ret = platform_driver_register(&cros_ec_lpc_driver);
	if (ret) {
	pr_err(DRV_NAME ": can't register driver: %d\n", ret);
	return ret;
	}

	/* Register the device, and it'll get hooked up automatically */
	ret = platform_device_register(&cros_ec_lpc_device);
	if (ret) {
	pr_err(DRV_NAME ": can't register device: %d\n", ret);
	platform_driver_unregister(&cros_ec_lpc_driver);
	return ret;
	}

	return 0;
	}

	static void __exit cros_ec_lpc_exit(void)
	{
	platform_device_unregister(&cros_ec_lpc_device);
	platform_driver_unregister(&cros_ec_lpc_driver);
	}

	module_init(cros_ec_lpc_init);
	module_exit(cros_ec_lpc_exit);

	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("ChromeOS EC LPC driver");