[PATCH linux dev-4.13 04/10] fsi/fsi-master-gpio: More error handling cleanup

[Christopher Bostic]

Reviewed-by: Christopher Bostic <cbostic at linux.vnet.ibm.com>


On 5/24/18 12:14 AM, Benjamin Herrenschmidt wrote:
> Remove calls to the empty and useless fsi_master_gpio_error()
> function, and report CRC errors as "FSI_ERR_NO_SLAVE" when
> reading an all 1's response.
>
> Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> ---
>   drivers/fsi/fsi-master-gpio.c | 26 +++++---------------------
>   1 file changed, 5 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/fsi/fsi-master-gpio.c b/drivers/fsi/fsi-master-gpio.c
> index 351c12f2ac55..da556da62846 100644
> --- a/drivers/fsi/fsi-master-gpio.c
> +++ b/drivers/fsi/fsi-master-gpio.c
> @@ -41,13 +41,6 @@
>   #define	FSI_GPIO_RESP_BUSY	1	/* Slave busy */
>   #define	FSI_GPIO_RESP_ERRA	2	/* Any (misc) Error */
>   #define	FSI_GPIO_RESP_ERRC	3	/* Slave reports master CRC error */
> -#define	FSI_GPIO_MTOE		4	/* Master time out error */
> -#define	FSI_GPIO_CRC_INVAL	5	/* Master reports slave CRC error */
> -
> -/* Normal slave responses */
> -#define	FSI_GPIO_RESP_BUSY	1
> -#define	FSI_GPIO_RESP_ACK	0
> -#define	FSI_GPIO_RESP_ACKD	4
>
>   #define	FSI_GPIO_MAX_BUSY	200
>   #define	FSI_GPIO_MTOE_COUNT	1000
> @@ -359,15 +352,6 @@ static void build_term_command(struct fsi_gpio_msg *cmd, uint8_t slave_id)
>   	msg_push_crc(cmd);
>   }
>
> -/*
> - * Store information on master errors so handler can detect and clean
> - * up the bus
> - */
> -static void fsi_master_gpio_error(struct fsi_master_gpio *master, int error)
> -{
> -
> -}
> -
>   /*
>    * Note: callers rely specifically on this returning -EAGAIN for
>    * a CRC error detected in the response. Use other error code
> @@ -396,7 +380,6 @@ static int read_one_response(struct fsi_master_gpio *master,
>   	if (i == FSI_GPIO_MTOE_COUNT) {
>   		dev_dbg(master->dev,
>   			"Master time out waiting for response\n");
> -		fsi_master_gpio_error(master, FSI_GPIO_MTOE);
>   		spin_unlock_irqrestore(&master->bit_lock, flags);
>   		return -ETIMEDOUT;
>   	}
> @@ -422,8 +405,11 @@ static int read_one_response(struct fsi_master_gpio *master,
>   	crc = crc4(0, 1, 1);
>   	crc = crc4(crc, msg.msg, msg.bits);
>   	if (crc) {
> -		dev_dbg(master->dev, "ERR response CRC\n");
> -		fsi_master_gpio_error(master, FSI_GPIO_CRC_INVAL);
> +		/* Check if it's all 1's, that probably means the host is off */
> +		if (((~msg.msg) & ((1ull << msg.bits) - 1)) == 0)
> +			return -ENODEV;
> +		dev_dbg(master->dev, "ERR response CRC msg: 0x%016llx (%d bits)\n",
> +			msg.msg, msg.bits);
>   		return -EAGAIN;
>   	}
>
> @@ -538,12 +524,10 @@ static int poll_for_response(struct fsi_master_gpio *master,
>
>   	case FSI_GPIO_RESP_ERRA:
>   		dev_dbg(master->dev, "ERRA received: 0x%x\n", (int)response.msg);
> -		fsi_master_gpio_error(master, response.msg);
>   		rc = -EIO;
>   		break;
>   	case FSI_GPIO_RESP_ERRC:
>   		dev_dbg(master->dev, "ERRC received: 0x%x\n", (int)response.msg);
> -		fsi_master_gpio_error(master, response.msg);
>   		trace_fsi_master_gpio_crc_cmd_error(master);
>   		rc = -EAGAIN;
>   		break;