Re: [PATCH 1/3] mfd: cros-ec: Add functions to read mapped memory

From: Guenter Roeck
Date: Thu Apr 13 2017 - 17:04:04 EST


On Fri, Apr 07, 2017 at 03:00:08PM -0700, 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.
>

Turns out struct cros_ec_device already provides a cmd_readmem callback,
which is widely used by other drivers. Why don't you just use it ?

Thanks,
Guenter

> Signed-off-by: Moritz Fischer <mdf@xxxxxxxxxx>
> ---
> 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;
> +
> + 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) {
> + 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);
> +
> +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.
> --
> 2.7.4
>