[PATCH v6] drivers: ipmi: Support raw i2c packet in IPMB

[Corey Minyard <cminyard@mvista.com>]

On Wed, Dec 11, 2019 at 10:56:04AM -0800, Vijay Khemka wrote:
> Many IPMB devices don't support smbus protocol and this driver
> only supports the smbus protocol at the moment.

Ok, I have this in.  Documentation/IPMB.txt had moved, I had to adjust
for that.

-corey

> 
> Added support for the i2c protocol as well. There will be a variable
> "i2c-protocol" passed by the device tree or ACPI table which determines
> whether the protocol is i2c or smbus.
> 
> Signed-off-by: Vijay Khemka <vijaykhemka@fb.com>
> Reviewed-by: Asmaa Mnebhi <asmaa@mellanox.com>
> ---
>  Documentation/IPMB.txt           |  4 ++++
>  drivers/char/ipmi/ipmb_dev_int.c | 29 +++++++++++++++++++++++++++++
>  2 files changed, 33 insertions(+)
> 
> diff --git a/Documentation/IPMB.txt b/Documentation/IPMB.txt
> index a6ed8b68bd0f..7a023beff976 100644
> --- a/Documentation/IPMB.txt
> +++ b/Documentation/IPMB.txt
> @@ -71,9 +71,13 @@ b) Example for device tree:
>           ipmb at 10 {
>                   compatible = "ipmb-dev";
>                   reg = <0x10>;
> +                 i2c-protocol;
>           };
>  };
>  
> +If xmit of data to be done using raw i2c block vs smbus
> +then "i2c-protocol" needs to be defined as above.
> +
>  2) Manually from Linux:
>  modprobe ipmb-dev-int
>  
> diff --git a/drivers/char/ipmi/ipmb_dev_int.c b/drivers/char/ipmi/ipmb_dev_int.c
> index ae3bfba27526..68a254c0dd92 100644
> --- a/drivers/char/ipmi/ipmb_dev_int.c
> +++ b/drivers/char/ipmi/ipmb_dev_int.c
> @@ -63,6 +63,7 @@ struct ipmb_dev {
>  	spinlock_t lock;
>  	wait_queue_head_t wait_queue;
>  	struct mutex file_mutex;
> +	bool is_i2c_protocol;
>  };
>  
>  static inline struct ipmb_dev *to_ipmb_dev(struct file *file)
> @@ -112,6 +113,25 @@ static ssize_t ipmb_read(struct file *file, char __user *buf, size_t count,
>  	return ret < 0 ? ret : count;
>  }
>  
> +static int ipmb_i2c_write(struct i2c_client *client, u8 *msg, u8 addr)
> +{
> +	struct i2c_msg i2c_msg;
> +
> +	/*
> +	 * subtract 1 byte (rq_sa) from the length of the msg passed to
> +	 * raw i2c_transfer
> +	 */
> +	i2c_msg.len = msg[IPMB_MSG_LEN_IDX] - 1;
> +
> +	/* Assign message to buffer except first 2 bytes (length and address) */
> +	i2c_msg.buf = msg + 2;
> +
> +	i2c_msg.addr = addr;
> +	i2c_msg.flags = client->flags & I2C_CLIENT_PEC;
> +
> +	return i2c_transfer(client->adapter, &i2c_msg, 1);
> +}
> +
>  static ssize_t ipmb_write(struct file *file, const char __user *buf,
>  			size_t count, loff_t *ppos)
>  {
> @@ -133,6 +153,12 @@ static ssize_t ipmb_write(struct file *file, const char __user *buf,
>  	rq_sa = GET_7BIT_ADDR(msg[RQ_SA_8BIT_IDX]);
>  	netf_rq_lun = msg[NETFN_LUN_IDX];
>  
> +	/* Check i2c block transfer vs smbus */
> +	if (ipmb_dev->is_i2c_protocol) {
> +		ret = ipmb_i2c_write(ipmb_dev->client, msg, rq_sa);
> +		return (ret == 1) ? count : ret;
> +	}
> +
>  	/*
>  	 * subtract rq_sa and netf_rq_lun from the length of the msg passed to
>  	 * i2c_smbus_xfer
> @@ -302,6 +328,9 @@ static int ipmb_probe(struct i2c_client *client,
>  	if (ret)
>  		return ret;
>  
> +	ipmb_dev->is_i2c_protocol
> +		= device_property_read_bool(&client->dev, "i2c-protocol");
> +
>  	ipmb_dev->client = client;
>  	i2c_set_clientdata(client, ipmb_dev);
>  	ret = i2c_slave_register(client, ipmb_slave_cb);
> -- 
> 2.17.1
>