On 04/07/2017 03:00 PM, Moritz Fischer wrote:
From: Moritz Fischer <mdf@xxxxxxxxxx>
The ChromeOS EC has mapped memory regions where things like temperature
sensors and fan speed are stored. Provide access to those from the
cros-ec mfd device.
Signed-off-by: Moritz Fischer <mdf@xxxxxxxxxx>
I'll have to consult with others at Google if this is a good idea.
Benson, can you comment ?
---
drivers/platform/chrome/cros_ec_proto.c | 55 +++++++++++++++++++++++++++++++++
include/linux/mfd/cros_ec.h | 39 +++++++++++++++++++++++
2 files changed, 94 insertions(+)
diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
index ed5dee7..28063de 100644
--- a/drivers/platform/chrome/cros_ec_proto.c
+++ b/drivers/platform/chrome/cros_ec_proto.c
@@ -494,3 +494,58 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev)
return get_keyboard_state_event(ec_dev);
}
EXPORT_SYMBOL(cros_ec_get_next_event);
+
+static int __cros_ec_read_mapped_mem(struct cros_ec_device *ec, uint8_t offset,
+ void *buf, size_t size)
+{
+ int ret;
+ struct ec_params_read_memmap *params;
+ struct cros_ec_command *msg;
+
+ msg = kzalloc(sizeof(*msg) + max(sizeof(*params), size), GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
I don't think using kzalloc here makes much sense. It is well known
that size is <= 4, so using a local buffer should not be a problem.
+ msg->version = 0;
+ msg->command = EC_CMD_READ_MEMMAP;
+ msg->insize = size;
+ msg->outsize = sizeof(*params);
+
+ params = (struct ec_params_read_memmap *)msg->data;
+ params->offset = offset;
+ params->size = size;
+
+ ret = cros_ec_cmd_xfer(ec, msg);
+ if (ret < 0 || msg->result != EC_RES_SUCCESS) {
cros_ec_cmd_xfer_status() was introduced to be able to avoid the second check.
+ dev_warn(ec->dev, "cannot read mapped reg: %d/%d\n",
+ ret, msg->result);
+ goto out_free;
+ }
+
+ memcpy(buf, msg->data, size);
+
+out_free:
+ kfree(msg);
+ return ret;
+}
+
+int cros_ec_read_mapped_mem32(struct cros_ec_device *ec, const uint8_t offset,
+ uint32_t *data)
+{
+ return __cros_ec_read_mapped_mem(ec, offset, data, sizeof(*data));
+}
+EXPORT_SYMBOL_GPL(cros_ec_read_mapped_mem32);
+
+int cros_ec_read_mapped_mem16(struct cros_ec_device *ec, const uint8_t offset,
+ uint16_t *data)
+{
+ return __cros_ec_read_mapped_mem(ec, offset, data, sizeof(*data));
+}
+EXPORT_SYMBOL_GPL(cros_ec_read_mapped_mem16);
+
Either case, this assumes that EC endianness matches host endianness. I don't
think we can just assume that this is the case.
+int cros_ec_read_mapped_mem8(struct cros_ec_device *ec, const uint8_t offset,
+ uint8_t *data)
+{
+ return __cros_ec_read_mapped_mem(ec, offset, data, sizeof(*data));
+}
+EXPORT_SYMBOL_GPL(cros_ec_read_mapped_mem8);
diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index b3d04de..c2de878 100644
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -190,6 +190,45 @@ struct cros_ec_dev {
};
/**
+ * cros_ec_read_mapped_mem8 - Read mapped memory in the ChromeOS EC
+ *
+ * This can be called by drivers to access the mapped memory in the EC
+ *
+ * @ec_dev: Device to read from
+ * @offset: Offset to read
+ * @data: Return data
+ * @return: 0 if Ok, -ve on error
+ */
+int cros_ec_read_mapped_mem8(struct cros_ec_device *ec, const uint8_t offset,
+ uint8_t *data);
+
+/**
+ * cros_ec_read_mapped_mem16 - Read mapped memory in the ChromeOS EC
+ *
+ * This can be called by drivers to access the mapped memory in the EC
+ *
+ * @ec_dev: Device to read from
+ * @offset: Offset to read
+ * @data: Return data
+ * @return: 0 if Ok, -ve on error
+ */
+int cros_ec_read_mapped_mem16(struct cros_ec_device *ec, const uint8_t offset,
+ uint16_t *data);
+
+/**
+ * cros_ec_read_mapped_mem32 - Read mapped memory in the ChromeOS EC
+ *
+ * This can be called by drivers to access the mapped memory in the EC
+ *
+ * @ec_dev: Device to read from
+ * @offset: Offset to read
+ * @data: Return data
+ * @return: 0 if Ok, -ve on error
+ */
+int cros_ec_read_mapped_mem32(struct cros_ec_device *ec, const uint8_t offset,
+ uint32_t *data);
+
+/**
* cros_ec_suspend - Handle a suspend operation for the ChromeOS EC device
*
* This can be called by drivers to handle a suspend event.
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