Re: [v6,10/23] drivers/fsi: Add device read/write/peek API

[Brad Bishop]

> On Apr 10, 2017, at 3:46 PM, Christopher Bostic <cbostic@xxxxxxxxxxxxxxxxxx> wrote:
> 
> From: Jeremy Kerr <jk@xxxxxxxxxx>
> 
> This change introduces the fsi device API: simple read, write and peek
> accessors for the devices' address spaces.
> 
> Includes contributions from Chris Bostic <cbostic@xxxxxxxxxxxxxxxxxx>
> and Edward A. James <eajames@xxxxxxxxxx>.
> 
> Signed-off-by: Edward A. James <eajames@xxxxxxxxxx>
> Signed-off-by: Jeremy Kerr <jk@xxxxxxxxxx>
> Signed-off-by: Chris Bostic <cbostic@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Joel Stanley <joel@xxxxxxxxx>
> ---
> drivers/fsi/fsi-core.c | 33 +++++++++++++++++++++++++++++++++
> include/linux/fsi.h    |  7 ++++++-
> 2 files changed, 39 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
> index a8faa89..4da0b030 100644
> --- a/drivers/fsi/fsi-core.c
> +++ b/drivers/fsi/fsi-core.c
> @@ -32,6 +32,8 @@
> #define FSI_SLAVE_CONF_CRC_MASK		0x0000000f
> #define FSI_SLAVE_CONF_DATA_BITS	28
> 
> +#define FSI_PEEK_BASE			0x410
> +
> static const int engine_page_size = 0x400;
> 
> #define FSI_SLAVE_BASE			0x800
> @@ -73,9 +75,40 @@ static int fsi_master_read(struct fsi_master *master, int link,
> 		uint8_t slave_id, uint32_t addr, void *val, size_t size);
> static int fsi_master_write(struct fsi_master *master, int link,
> 		uint8_t slave_id, uint32_t addr, const void *val, size_t size);
> +static int fsi_slave_read(struct fsi_slave *slave, uint32_t addr,
> +		void *val, size_t size);
> +static int fsi_slave_write(struct fsi_slave *slave, uint32_t addr,
> +		const void *val, size_t size);
> 
> /* FSI endpoint-device support */
> 
> +int fsi_device_read(struct fsi_device *dev, uint32_t addr, void *val,
> +		size_t size)
> +{
> +	if (addr > dev->size || size > dev->size || addr > dev->size - size)
> +		return -EINVAL;
> +
> +	return fsi_slave_read(dev->slave, dev->addr + addr, val, size);
> +}
> +EXPORT_SYMBOL_GPL(fsi_device_read);
> +
> +int fsi_device_write(struct fsi_device *dev, uint32_t addr, const void *val,
> +		size_t size)
> +{
> +	if (addr > dev->size || size > dev->size || addr > dev->size - size)
> +		return -EINVAL;
> +
> +	return fsi_slave_write(dev->slave, dev->addr + addr, val, size);
> +}
> +EXPORT_SYMBOL_GPL(fsi_device_write);
> +
> +int fsi_device_peek(struct fsi_device *dev, void *val)
> +{
> +	uint32_t addr = FSI_PEEK_BASE + ((dev->unit - 2) * sizeof(uint32_t));
> +
> +	return fsi_slave_read(dev->slave, addr, val, sizeof(uint32_t));
> +}
> +
> static void fsi_device_release(struct device *_device)
> {
> 	struct fsi_device *device = to_fsi_dev(_device);
> diff --git a/include/linux/fsi.h b/include/linux/fsi.h
> index efa55ba..66bce48 100644
> --- a/include/linux/fsi.h
> +++ b/include/linux/fsi.h
> @@ -27,6 +27,12 @@ struct fsi_device {
> 	uint32_t		size;
> };
> 
> +extern int fsi_device_read(struct fsi_device *dev, uint32_t addr,
> +		void *val, size_t size);
> +extern int fsi_device_write(struct fsi_device *dev, uint32_t addr,
> +		const void *val, size_t size);
> +extern int fsi_device_peek(struct fsi_device *dev, void *val);
> +
> struct fsi_device_id {
> 	u8	engine_type;
> 	u8	version;
> @@ -40,7 +46,6 @@ struct fsi_device_id {
> #define FSI_DEVICE_VERSIONED(t, v) \
> 	.engine_type = (t), .version = (v),
> 
> -
> struct fsi_driver {
> 	struct device_driver		drv;
> 	const struct fsi_device_id	*id_table;

I wrote a driver using this API.  It seems to be suitable enough.

Acked-by: Brad Bishop <bradleyb@xxxxxxxxxxxxxxxxxx>