platform/chrome: Fix MEC concurrency problems for Framework Laptop

index ddfbfec44f4c..6663141a07d4 100644
@@ -62,14 +62,16 @@ struct cros_ec_lpc {
 
 /**
  * struct lpc_driver_ops - LPC driver operations
- * @read: Copy length bytes from EC address offset into buffer dest. Returns
- *        the 8-bit checksum of all bytes read.
- * @write: Copy length bytes from buffer msg into EC address offset. Returns
- *         the 8-bit checksum of all bytes written.
+ * @read: Copy length bytes from EC address offset into buffer dest.
+ *        Returns a negative error code on error, or the 8-bit checksum
+ *        of all bytes read.
+ * @write: Copy length bytes from buffer msg into EC address offset.
+ *         Returns a negative error code on error, or the 8-bit checksum
+ *         of all bytes written.
  */
 struct lpc_driver_ops {
-	u8 (*read)(unsigned int offset, unsigned int length, u8 *dest);
-	u8 (*write)(unsigned int offset, unsigned int length, const u8 *msg);
+	int (*read)(unsigned int offset, unsigned int length, u8 *dest);
+	int (*write)(unsigned int offset, unsigned int length, const u8 *msg);
 };
 
 static struct lpc_driver_ops cros_ec_lpc_ops = { };

@@ -78,10 +80,10 @@ static struct lpc_driver_ops cros_ec_lpc_ops = { };
  * A generic instance of the read function of struct lpc_driver_ops, used for
  * the LPC EC.
  */
-static u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length,
-				 u8 *dest)
+static int cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length,
+				  u8 *dest)
 {
-	int sum = 0;
+	u8 sum = 0;
 	int i;
 
 	for (i = 0; i < length; ++i) {

@@ -97,10 +99,10 @@ static u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length,
  * A generic instance of the write function of struct lpc_driver_ops, used for
  * the LPC EC.
  */
-static u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length,
-				  const u8 *msg)
+static int cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length,
+				   const u8 *msg)
 {
-	int sum = 0;
+	u8 sum = 0;
 	int i;
 
 	for (i = 0; i < length; ++i) {

@@ -116,8 +118,8 @@ static u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length,
  * An instance of the read function of struct lpc_driver_ops, used for the
  * MEC variant of LPC EC.
  */
-static u8 cros_ec_lpc_mec_read_bytes(unsigned int offset, unsigned int length,
-				     u8 *dest)
+static int cros_ec_lpc_mec_read_bytes(unsigned int offset, unsigned int length,
+				      u8 *dest)
 {
 	int in_range = cros_ec_lpc_mec_in_range(offset, length);
 

@@ -135,8 +137,8 @@ static u8 cros_ec_lpc_mec_read_bytes(unsigned int offset, unsigned int length,
  * An instance of the write function of struct lpc_driver_ops, used for the
  * MEC variant of LPC EC.
  */
-static u8 cros_ec_lpc_mec_write_bytes(unsigned int offset, unsigned int length,
-				      const u8 *msg)
+static int cros_ec_lpc_mec_write_bytes(unsigned int offset, unsigned int length,
+				       const u8 *msg)
 {
 	int in_range = cros_ec_lpc_mec_in_range(offset, length);
 

@@ -154,11 +156,14 @@ static int ec_response_timed_out(void)
 {
 	unsigned long one_second = jiffies + HZ;
 	u8 data;
+	int ret;
 
 	usleep_range(200, 300);
 	do {
-		if (!(cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_CMD, 1, &data) &
-		    EC_LPC_STATUS_BUSY_MASK))
+		ret = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_CMD, 1, &data);
+		if (ret < 0)
+			return ret;
+		if (!(data & EC_LPC_STATUS_BUSY_MASK))
 			return 0;
 		usleep_range(100, 200);
 	} while (time_before(jiffies, one_second));

@@ -179,28 +184,41 @@ static int cros_ec_pkt_xfer_lpc(struct cros_ec_device *ec,
 		goto done;
 
 	/* Write buffer */
-	cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_PACKET, ret, ec->dout);
+	ret = cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_PACKET, ret, ec->dout);
+	if (ret < 0)
+		goto done;
 
 	/* Here we go */
 	sum = EC_COMMAND_PROTOCOL_3;
-	cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_CMD, 1, &sum);
+	ret = cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_CMD, 1, &sum);
+	if (ret < 0)
+		goto done;
 
-	if (ec_response_timed_out()) {
+	ret = ec_response_timed_out();
+	if (ret < 0)
+		goto done;
+	if (ret) {
 		dev_warn(ec->dev, "EC response timed out\n");
 		ret = -EIO;
 		goto done;
 	}
 
 	/* Check result */
-	msg->result = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_DATA, 1, &sum);
+	ret = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_DATA, 1, &sum);
+	if (ret < 0)
+		goto done;
+	msg->result = ret;
 	ret = cros_ec_check_result(ec, msg);
 	if (ret)
 		goto done;
 
 	/* Read back response */
 	dout = (u8 *)&response;
-	sum = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PACKET, sizeof(response),
+	ret = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PACKET, sizeof(response),
 				   dout);
+	if (ret < 0)
+		goto done;
+	sum = ret;
 
 	msg->result = response.result;
 

@@ -213,9 +231,12 @@ static int cros_ec_pkt_xfer_lpc(struct cros_ec_device *ec,
 	}
 
 	/* Read response and process checksum */
-	sum += cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PACKET +
-				    sizeof(response), response.data_len,
-				    msg->data);
+	ret = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PACKET +
+				   sizeof(response), response.data_len,
+				   msg->data);
+	if (ret < 0)
+		goto done;
+	sum += ret;
 
 	if (sum) {
 		dev_err(ec->dev,

@@ -255,32 +276,47 @@ static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec,
 	sum = msg->command + args.flags + args.command_version + args.data_size;
 
 	/* Copy data and update checksum */
-	sum += cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_PARAM, msg->outsize,
-				     msg->data);
+	ret = cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_PARAM, msg->outsize,
+				    msg->data);
+	if (ret < 0)
+		goto done;
+	sum += ret;
 
 	/* Finalize checksum and write args */
 	args.checksum = sum;
-	cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_ARGS, sizeof(args),
-			      (u8 *)&args);
+	ret = cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_ARGS, sizeof(args),
+				    (u8 *)&args);
+	if (ret < 0)
+		goto done;
 
 	/* Here we go */
 	sum = msg->command;
-	cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_CMD, 1, &sum);
+	ret = cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_CMD, 1, &sum);
+	if (ret < 0)
+		goto done;
 
-	if (ec_response_timed_out()) {
+	ret = ec_response_timed_out();
+	if (ret < 0)
+		goto done;
+	if (ret) {
 		dev_warn(ec->dev, "EC response timed out\n");
 		ret = -EIO;
 		goto done;
 	}
 
 	/* Check result */
-	msg->result = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_DATA, 1, &sum);
+	ret = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_DATA, 1, &sum);
+	if (ret < 0)
+		goto done;
+	msg->result = ret;
 	ret = cros_ec_check_result(ec, msg);
 	if (ret)
 		goto done;
 
 	/* Read back args */
-	cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_ARGS, sizeof(args), (u8 *)&args);
+	ret = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_ARGS, sizeof(args), (u8 *)&args);
+	if (ret < 0)
+		goto done;
 
 	if (args.data_size > msg->insize) {
 		dev_err(ec->dev,

@@ -294,8 +330,11 @@ static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec,
 	sum = msg->command + args.flags + args.command_version + args.data_size;
 
 	/* Read response and update checksum */
-	sum += cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PARAM, args.data_size,
-				    msg->data);
+	ret = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PARAM, args.data_size,
+				   msg->data);
+	if (ret < 0)
+		goto done;
+	sum += ret;
 
 	/* Verify checksum */
 	if (args.checksum != sum) {

@@ -320,19 +359,24 @@ static int cros_ec_lpc_readmem(struct cros_ec_device *ec, unsigned int offset,
 	int i = offset;
 	char *s = dest;
 	int cnt = 0;
+	int ret;
 
 	if (offset >= EC_MEMMAP_SIZE - bytes)
 		return -EINVAL;
 
 	/* fixed length */
 	if (bytes) {
-		cros_ec_lpc_ops.read(ec_lpc->mmio_memory_base + offset, bytes, s);
+		ret = cros_ec_lpc_ops.read(ec_lpc->mmio_memory_base + offset, bytes, s);
+		if (ret < 0)
+			return ret;
 		return bytes;
 	}
 
 	/* string */
 	for (; i < EC_MEMMAP_SIZE; i++, s++) {
-		cros_ec_lpc_ops.read(ec_lpc->mmio_memory_base + i, 1, s);
+		ret = cros_ec_lpc_ops.read(ec_lpc->mmio_memory_base + i, 1, s);
+		if (ret < 0)
+			return ret;
 		cnt++;
 		if (!*s)
 			break;

@@ -425,8 +469,8 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
 	 */
 	cros_ec_lpc_ops.read = cros_ec_lpc_mec_read_bytes;
 	cros_ec_lpc_ops.write = cros_ec_lpc_mec_write_bytes;
-	cros_ec_lpc_ops.read(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID, 2, buf);
-	if (buf[0] != 'E' || buf[1] != 'C') {
+	ret = cros_ec_lpc_ops.read(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID, 2, buf);
+	if (ret < 0 || buf[0] != 'E' || buf[1] != 'C') {
 		if (!devm_request_region(dev, ec_lpc->mmio_memory_base, EC_MEMMAP_SIZE,
 					 dev_name(dev))) {
 			dev_err(dev, "couldn't reserve memmap region\n");

@@ -436,9 +480,9 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
 		/* Re-assign read/write operations for the non MEC variant */
 		cros_ec_lpc_ops.read = cros_ec_lpc_read_bytes;
 		cros_ec_lpc_ops.write = cros_ec_lpc_write_bytes;
-		cros_ec_lpc_ops.read(ec_lpc->mmio_memory_base + EC_MEMMAP_ID, 2,
-				     buf);
-		if (buf[0] != 'E' || buf[1] != 'C') {
+		ret = cros_ec_lpc_ops.read(ec_lpc->mmio_memory_base + EC_MEMMAP_ID, 2,
+					   buf);
+		if (ret < 0 || buf[0] != 'E' || buf[1] != 'C') {
 			dev_err(dev, "EC ID not detected\n");
 			return -ENODEV;
 		}

index 0d9c79b270ce..395dc3a6fb5e 100644
@@ -67,11 +67,12 @@ int cros_ec_lpc_mec_in_range(unsigned int offset, unsigned int length)
  * @length:  Number of bytes to read / write
  * @buf:     Destination / source buffer
  *
- * Return: 8-bit checksum of all bytes read / written
+ * @return:  A negative error code on error, or 8-bit checksum of all
+ *           bytes read / written
  */
-u8 cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,
-			    unsigned int offset, unsigned int length,
-			    u8 *buf)
+int cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,
+			     unsigned int offset, unsigned int length,
+			     u8 *buf)
 {
 	int i = 0;
 	int io_addr;

index 9d0521b23e8a..69670832f187 100644
@@ -64,9 +64,10 @@ int cros_ec_lpc_mec_in_range(unsigned int offset, unsigned int length);
  * @length:  Number of bytes to read / write
  * @buf:     Destination / source buffer
  *
- * @return 8-bit checksum of all bytes read / written
+ * @return:  A negative error code on error, or 8-bit checksum of all
+ *           bytes read / written
  */
-u8 cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,
-			    unsigned int offset, unsigned int length, u8 *buf);
+int cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,
+			     unsigned int offset, unsigned int length, u8 *buf);
 
 #endif /* __CROS_EC_LPC_MEC_H */

index 0f98358ea824..4d8273b47cde 100644
@@ -117,13 +117,17 @@ static int wilco_ec_transfer(struct wilco_ec_device *ec,
 			     struct wilco_ec_request *rq)
 {
 	struct wilco_ec_response *rs;
-	u8 checksum;
+	int ret;
 	u8 flag;
 
 	/* Write request header, then data */
-	cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, 0, sizeof(*rq), (u8 *)rq);
-	cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, sizeof(*rq), msg->request_size,
-				 msg->request_data);
+	ret = cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, 0, sizeof(*rq), (u8 *)rq);
+	if (ret < 0)
+		return ret;
+	ret = cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, sizeof(*rq), msg->request_size,
+				       msg->request_data);
+	if (ret < 0)
+		return ret;
 
 	/* Start the command */
 	outb(EC_MAILBOX_START_COMMAND, ec->io_command->start);

@@ -149,10 +153,12 @@ static int wilco_ec_transfer(struct wilco_ec_device *ec,
 
 	/* Read back response */
 	rs = ec->data_buffer;
-	checksum = cros_ec_lpc_io_bytes_mec(MEC_IO_READ, 0,
-					    sizeof(*rs) + EC_MAILBOX_DATA_SIZE,
-					    (u8 *)rs);
-	if (checksum) {
+	ret = cros_ec_lpc_io_bytes_mec(MEC_IO_READ, 0,
+				       sizeof(*rs) + EC_MAILBOX_DATA_SIZE,
+				       (u8 *)rs);
+	if (ret < 0)
+		return ret;
+	if (ret) {
 		dev_dbg(ec->dev, "bad packet checksum 0x%02x\n", rs->checksum);
 		return -EBADMSG;
 	}

index 395dc3a6fb5e..fce1bdfb0a64 100644
@@ -10,13 +10,67 @@
 
 #include "cros_ec_lpc_mec.h"
 
+#define ACPI_LOCK_DELAY_MS 500
+
 /*
  * This mutex must be held while accessing the EMI unit. We can't rely on the
  * EC mutex because memmap data may be accessed without it being held.
  */
 static DEFINE_MUTEX(io_mutex);
+/*
+ * An alternative mutex to be used when the ACPI AML code may also
+ * access memmap data.  When set, this mutex is used in preference to
+ * io_mutex.
+ */
+static acpi_handle aml_mutex;
+
 static u16 mec_emi_base, mec_emi_end;
 
+/**
+ * cros_ec_lpc_mec_lock() - Acquire mutex for EMI
+ *
+ * @return: Negative error code, or zero for success
+ */
+static int cros_ec_lpc_mec_lock(void)
+{
+	bool success;
+
+	if (!aml_mutex) {
+		mutex_lock(&io_mutex);
+		return 0;
+	}
+
+	success = ACPI_SUCCESS(acpi_acquire_mutex(aml_mutex,
+						  NULL, ACPI_LOCK_DELAY_MS));
+
+	if (!success)
+		return -EBUSY;
+
+	return 0;
+}
+
+/**
+ * cros_ec_lpc_mec_unlock() - Release mutex for EMI
+ *
+ * @return: Negative error code, or zero for success
+ */
+static int cros_ec_lpc_mec_unlock(void)
+{
+	bool success;
+
+	if (!aml_mutex) {
+		mutex_unlock(&io_mutex);
+		return 0;
+	}
+
+	success = ACPI_SUCCESS(acpi_release_mutex(aml_mutex, NULL));
+
+	if (!success)
+		return -EBUSY;
+
+	return 0;
+}
+
 /**
  * cros_ec_lpc_mec_emi_write_address() - Initialize EMI at a given address.
  *

@@ -78,6 +132,7 @@ int cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,
 	int io_addr;
 	u8 sum = 0;
 	enum cros_ec_lpc_mec_emi_access_mode access, new_access;
+	int ret;
 
 	/* Return checksum of 0 if window is not initialized */
 	WARN_ON(mec_emi_base == 0 || mec_emi_end == 0);

@@ -93,7 +148,9 @@ int cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,
 	else
 		access = ACCESS_TYPE_LONG_AUTO_INCREMENT;
 
-	mutex_lock(&io_mutex);
+	ret = cros_ec_lpc_mec_lock();
+	if (ret)
+		return ret;
 
 	/* Initialize I/O at desired address */
 	cros_ec_lpc_mec_emi_write_address(offset, access);

@@ -135,7 +192,9 @@ int cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,
 	}
 
 done:
-	mutex_unlock(&io_mutex);
+	ret = cros_ec_lpc_mec_unlock();
+	if (ret < 0)
+		return ret;
 
 	return sum;
 }

@@ -147,3 +206,18 @@ void cros_ec_lpc_mec_init(unsigned int base, unsigned int end)
 	mec_emi_end = end;
 }
 EXPORT_SYMBOL(cros_ec_lpc_mec_init);
+
+int cros_ec_lpc_mec_acpi_mutex(struct acpi_device *adev, const char *pathname)
+{
+	int status;
+
+	if (!adev)
+		return -ENOENT;
+
+	status = acpi_get_handle(adev->handle, pathname, &aml_mutex);
+	if (ACPI_FAILURE(status))
+		return -ENOENT;
+
+	return 0;
+}
+EXPORT_SYMBOL(cros_ec_lpc_mec_acpi_mutex);

index 69670832f187..69f9d8786f61 100644
@@ -8,6 +8,8 @@
 #ifndef __CROS_EC_LPC_MEC_H
 #define __CROS_EC_LPC_MEC_H
 
+#include <linux/acpi.h>
+
 enum cros_ec_lpc_mec_emi_access_mode {
 	/* 8-bit access */
 	ACCESS_TYPE_BYTE = 0x0,

@@ -45,6 +47,15 @@ enum cros_ec_lpc_mec_io_type {
  */
 void cros_ec_lpc_mec_init(unsigned int base, unsigned int end);
 
+/**
+ * cros_ec_lpc_mec_acpi_mutex() - Find and set ACPI mutex for MEC
+ *
+ * @adev:     Parent ACPI device
+ * @pathname: Name of AML mutex
+ * @return:   Negative error code, or zero for success
+ */
+int cros_ec_lpc_mec_acpi_mutex(struct acpi_device *adev, const char *pathname);
+
 /**
  * cros_ec_lpc_mec_in_range() - Determine if addresses are in MEC EMI range.
  *

index 6663141a07d4..c1c26a7ba6d4 100644
@@ -39,6 +39,11 @@ static bool cros_ec_lpc_acpi_device_found;
  * be used as the base port for EC mapped memory.
  */
 #define CROS_EC_LPC_QUIRK_REMAP_MEMORY              BIT(0)
+/*
+ * Indicates that lpc_driver_data.quirk_acpi_id should be used to find
+ * the ACPI device.
+ */
+#define CROS_EC_LPC_QUIRK_ACPI_ID                   BIT(1)
 
 /**
  * struct lpc_driver_data - driver data attached to a DMI device ID to indicate

@@ -46,10 +51,12 @@ static bool cros_ec_lpc_acpi_device_found;
  * @quirks: a bitfield composed of quirks from CROS_EC_LPC_QUIRK_*
  * @quirk_mmio_memory_base: The first I/O port addressing EC mapped memory (used
  *                          when quirk ...REMAP_MEMORY is set.)
+ * @quirk_acpi_id: An ACPI HID to be used to find the ACPI device.
  */
 struct lpc_driver_data {
 	u32 quirks;
 	u16 quirk_mmio_memory_base;
+	const char *quirk_acpi_id;
 };
 
 /**

@@ -418,6 +425,26 @@ static void cros_ec_lpc_acpi_notify(acpi_handle device, u32 value, void *data)
 		pm_system_wakeup();
 }
 
+static acpi_status cros_ec_lpc_parse_device(acpi_handle handle, u32 level,
+					    void *context, void **retval)
+{
+	*(struct acpi_device **)context = acpi_fetch_acpi_dev(handle);
+	return AE_CTRL_TERMINATE;
+}
+
+static struct acpi_device *cros_ec_lpc_get_device(const char *id)
+{
+	struct acpi_device *adev = NULL;
+	acpi_status status = acpi_get_devices(id, cros_ec_lpc_parse_device,
+					      &adev, NULL);
+	if (ACPI_FAILURE(status)) {
+		pr_warn(DRV_NAME ": Looking for %s failed\n", id);
+		return NULL;
+	}
+
+	return adev;
+}
+
 static int cros_ec_lpc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;

@@ -436,6 +463,8 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
 
 	ec_lpc->mmio_memory_base = EC_LPC_ADDR_MEMMAP;
 
+	adev = ACPI_COMPANION(dev);
+
 	driver_data = platform_get_drvdata(pdev);
 	if (driver_data) {
 		quirks = driver_data->quirks;

@@ -445,6 +474,16 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
 
 		if (quirks & CROS_EC_LPC_QUIRK_REMAP_MEMORY)
 			ec_lpc->mmio_memory_base = driver_data->quirk_mmio_memory_base;
+
+		if (quirks & CROS_EC_LPC_QUIRK_ACPI_ID) {
+			adev = cros_ec_lpc_get_device(driver_data->quirk_acpi_id);
+			if (!adev) {
+				dev_err(dev, "failed to get ACPI device '%s'",
+					driver_data->quirk_acpi_id);
+				return -ENODEV;
+			}
+			ACPI_COMPANION_SET(dev, adev);
+		}
 	}
 
 	/*

@@ -538,7 +577,6 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
 	 * Connect a notify handler to process MKBP messages if we have a
 	 * companion ACPI device.
 	 */
-	adev = ACPI_COMPANION(dev);
 	if (adev) {
 		status = acpi_install_notify_handler(adev->handle,
 						     ACPI_ALL_NOTIFY,

@@ -705,23 +743,12 @@ static struct platform_device cros_ec_lpc_device = {
 	.name = DRV_NAME
 };
 
-static acpi_status cros_ec_lpc_parse_device(acpi_handle handle, u32 level,
-					    void *context, void **retval)
-{
-	*(bool *)context = true;
-	return AE_CTRL_TERMINATE;
-}
-
 static int __init cros_ec_lpc_init(void)
 {
 	int ret;
-	acpi_status status;
 	const struct dmi_system_id *dmi_match;
 
-	status = acpi_get_devices(ACPI_DRV_NAME, cros_ec_lpc_parse_device,
-				  &cros_ec_lpc_acpi_device_found, NULL);
-	if (ACPI_FAILURE(status))
-		pr_warn(DRV_NAME ": Looking for %s failed\n", ACPI_DRV_NAME);
+	cros_ec_lpc_acpi_device_found = !!cros_ec_lpc_get_device(ACPI_DRV_NAME);
 
 	dmi_match = dmi_first_match(cros_ec_lpc_dmi_table);
 

index c1c26a7ba6d4..60627c5a596b 100644
@@ -44,6 +44,11 @@ static bool cros_ec_lpc_acpi_device_found;
  * the ACPI device.
  */
 #define CROS_EC_LPC_QUIRK_ACPI_ID                   BIT(1)
+/*
+ * Indicates that lpc_driver_data.quirk_aml_mutex_name should be used
+ * to find an AML mutex to protect access to Microchip EC.
+ */
+#define CROS_EC_LPC_QUIRK_AML_MUTEX                 BIT(2)
 
 /**
  * struct lpc_driver_data - driver data attached to a DMI device ID to indicate

@@ -52,11 +57,14 @@ static bool cros_ec_lpc_acpi_device_found;
  * @quirk_mmio_memory_base: The first I/O port addressing EC mapped memory (used
  *                          when quirk ...REMAP_MEMORY is set.)
  * @quirk_acpi_id: An ACPI HID to be used to find the ACPI device.
+ * @quirk_aml_mutex_name: The name of an AML mutex to be used to protect access
+ *                        to Microchip EC.
  */
 struct lpc_driver_data {
 	u32 quirks;
 	u16 quirk_mmio_memory_base;
 	const char *quirk_acpi_id;
+	const char *quirk_aml_mutex_name;
 };
 
 /**

@@ -484,6 +492,18 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
 			}
 			ACPI_COMPANION_SET(dev, adev);
 		}
+
+		if (quirks & CROS_EC_LPC_QUIRK_AML_MUTEX) {
+			const char *name
+				= driver_data->quirk_aml_mutex_name;
+			ret = cros_ec_lpc_mec_acpi_mutex(adev, name);
+			if (ret) {
+				dev_err(dev, "failed to get AML mutex '%s'", name);
+				return ret;
+			}
+
+			dev_info(dev, "got AML mutex '%s'", name);
+		}
 	}
 
 	/*

index 60627c5a596b..bebf76404512 100644
@@ -634,6 +634,12 @@ static const struct lpc_driver_data framework_laptop_amd_lpc_driver_data __initc
 	.quirk_mmio_memory_base = 0xE00,
 };
 
+static const struct lpc_driver_data framework_laptop_11_lpc_driver_data __initconst = {
+	.quirks = CROS_EC_LPC_QUIRK_ACPI_ID|CROS_EC_LPC_QUIRK_AML_MUTEX,
+	.quirk_acpi_id = "PNP0C09",
+	.quirk_aml_mutex_name = "ECMT",
+};
+
 static const struct dmi_system_id cros_ec_lpc_dmi_table[] __initconst = {
 	{
 		/*

@@ -702,6 +708,7 @@ static const struct dmi_system_id cros_ec_lpc_dmi_table[] __initconst = {
 			DMI_MATCH(DMI_SYS_VENDOR, "Framework"),
 			DMI_MATCH(DMI_PRODUCT_NAME, "Laptop"),
 		},
+		.driver_data = (void *)&framework_laptop_11_lpc_driver_data,
 	},
 	{ /* sentinel */ }
 };