[PATCH linux dev-4.7 v3 2/2] drivers/fsi: Cleanup and retry op on error

[Eddie James]

Acked-by: Eddie James <eajames at linux.vnet.ibm.com>


On 02/23/2017 01:58 PM, Christopher Bostic wrote:
> On detect of FSI bus error clean up the bus and then retry
> the original operation.
>
> Signed-off-by: Christopher Bostic <cbostic at linux.vnet.ibm.com>
>
> v3 - Move comon read/write code into a retry utility
>
>     - Add comment on why trying again
>
>     - Change nested error check from atomic bit type to atomic_t
>
>     - loop on retry instead of duplicating the same code
> ---
>   drivers/fsi/fsi-core.c        | 30 ++++++++++++++++++++++++++++++
>   drivers/fsi/fsi-master-gpio.c | 28 ++++++++++++++++++++++++++--
>   drivers/fsi/fsi-master.h      |  1 +
>   3 files changed, 57 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
> index 02ca3c0..a7b705d 100644
> --- a/drivers/fsi/fsi-core.c
> +++ b/drivers/fsi/fsi-core.c
> @@ -42,6 +42,9 @@
>
>   #define FSI_PEEK_BASE			0x410
>   #define	FSI_SLAVE_BASE			0x800
> +#define	FSI_HUB_CONTROL			0x3400
> +
> +#define	FSI_SLAVE_SMODE_DFLT		0xa0ff0100
>
>   #define FSI_IPOLL_PERIOD		msecs_to_jiffies(fsi_ipoll_period_ms)
>
> @@ -55,6 +58,7 @@ static const int engine_page_size = 0x400;
>   static struct task_struct *master_ipoll;
>   static unsigned int fsi_ipoll_period_ms = 100;
>   struct class *hub_master_class;
> +static atomic_t in_err_cleanup = ATOMIC_INIT(-1);
>
>   static DEFINE_IDA(master_ida);
>
> @@ -653,6 +657,32 @@ static int fsi_master_break(struct fsi_master *master, int link)
>   	return 0;
>   }
>
> +void fsi_master_handle_error(struct fsi_master *master, uint32_t addr)
> +{
> +	uint32_t smode = FSI_SLAVE_SMODE_DFLT;
> +
> +	if (!atomic_inc_and_test(&in_err_cleanup))
> +		return;
> +
> +	fsi_master_break(master, 0);
> +	udelay(200);
> +	master->write(master, 0, 0, FSI_SLAVE_BASE + FSI_SMODE, &smode,
> +			sizeof(smode));
> +	smode = FSI_MRESB_RST_GEN | FSI_MRESB_RST_ERR;
> +	master->write(master, 0, 0, FSI_HUB_CONTROL + FSI_MRESB0, &smode,
> +		sizeof(smode));
> +
> +	if (addr > FSI_HUB_LINK_OFFSET) {
> +		smode = FSI_BREAK;
> +		master->write(master, 0, 0, 0x100004, &smode, sizeof(smode));
> +		smode = FSI_SLAVE_SMODE_DFLT;
> +		master->write(master, 0, 0, 0x100800, &smode, sizeof(smode));
> +	}
> +
> +	atomic_set(&in_err_cleanup, -1);
> +}
> +EXPORT_SYMBOL(fsi_master_handle_error);
> +
>   static int fsi_master_scan(struct fsi_master *master)
>   {
>   	int link, slave_id, rc;
> diff --git a/drivers/fsi/fsi-master-gpio.c b/drivers/fsi/fsi-master-gpio.c
> index b6feec1..c5f4f9c 100644
> --- a/drivers/fsi/fsi-master-gpio.c
> +++ b/drivers/fsi/fsi-master-gpio.c
> @@ -370,6 +370,28 @@ static int send_command(struct fsi_master_gpio *master,
>   	return rc;
>   }
>
> +static int fsi_master_gpio_send(struct fsi_master_gpio *master,
> +				struct fsi_gpio_msg *cmd, uint8_t expected,
> +				uint32_t addr, size_t size, void *val)
> +{
> +	static const int master_retries = 2;
> +	uint8_t retries;
> +	int rc;
> +
> +	/*
> +	 * In case the FSI bus is in a bad state a retry may help
> +	 * the operation to complete successfully
> +	 */
> +	for (retries = 0; retries < master_retries; retries++) {
> +		rc = send_command(master, cmd, expected, size, val);
> +		if (!rc)
> +			break;
> +		fsi_master_handle_error(&master->master, addr);
> +	}
> +
> +	return rc;
> +}
> +
>   static int fsi_master_gpio_read(struct fsi_master *_master, int link,
>   		uint8_t slave, uint32_t addr, void *val, size_t size)
>   {
> @@ -380,7 +402,8 @@ static int fsi_master_gpio_read(struct fsi_master *_master, int link,
>   		return -ENODEV;
>
>   	build_abs_ar_command(&cmd, FSI_GPIO_CMD_READ, slave, addr, size, NULL);
> -	return send_command(master, &cmd, FSI_GPIO_RESP_ACKD, size, val);
> +	return fsi_master_gpio_send(master, &cmd, FSI_GPIO_RESP_ACKD, addr,
> +				size, val);
>   }
>
>   static int fsi_master_gpio_write(struct fsi_master *_master, int link,
> @@ -393,7 +416,8 @@ static int fsi_master_gpio_write(struct fsi_master *_master, int link,
>   		return -ENODEV;
>
>   	build_abs_ar_command(&cmd, FSI_GPIO_CMD_WRITE, slave, addr, size, val);
> -	return send_command(master, &cmd, FSI_GPIO_RESP_ACK, size, NULL);
> +	return fsi_master_gpio_send(master, &cmd, FSI_GPIO_RESP_ACK, addr,
> +				size, NULL);
>   }
>
>   /*
> diff --git a/drivers/fsi/fsi-master.h b/drivers/fsi/fsi-master.h
> index 4a3176b..54723a7 100644
> --- a/drivers/fsi/fsi-master.h
> +++ b/drivers/fsi/fsi-master.h
> @@ -85,6 +85,7 @@ struct fsi_master {
>   extern int fsi_master_register(struct fsi_master *master);
>   extern void fsi_master_unregister(struct fsi_master *master);
>   extern int fsi_master_start_ipoll(struct fsi_master *master);
> +extern void fsi_master_handle_error(struct fsi_master *master, uint32_t addr);
>
>   /**
>    * crc4 helper: Given a starting crc4 state @c, calculate the crc4 vaue of @x,