mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-24 11:40:53 +07:00
fsi/fsi-master-gpio: Implement CRC error recovery
The FSI protocol defines two modes of recovery from CRC errors, this implements both: - If the device returns an ECRC (it detected a CRC error in the command), then we simply issue the command again. - If the master detects a CRC error in the response, we send an E_POLL command which requests a resend of the response without actually re-executing the command (which could otherwise have unwanted side effects such as dequeuing a FIFO twice). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com> Tested-by: Joel Stanley <joel@jms.id.au> --- Note: This was actually tested by removing some of my fixes, thus causing us to hit occasional CRC errors during high LPC activity.
This commit is contained in:
Benjamin Herrenschmidt
parent
0e82e5c1fa
commit
4e56828a5d
@ -22,20 +22,23 @@
|
||||
#define FSI_BREAK_CLOCKS 256 /* Number of clocks to issue break */
|
||||
#define FSI_POST_BREAK_CLOCKS 16000 /* Number clocks to set up cfam */
|
||||
#define FSI_INIT_CLOCKS 5000 /* Clock out any old data */
|
||||
#define FSI_GPIO_DPOLL_CLOCKS 50 /* < 21 will cause slave to hang */
|
||||
#define FSI_GPIO_EPOLL_CLOCKS 50 /* Number of clocks for E_POLL retry */
|
||||
#define FSI_GPIO_STD_DELAY 10 /* Standard GPIO delay in nS */
|
||||
/* todo: adjust down as low as */
|
||||
/* possible or eliminate */
|
||||
#define FSI_CRC_ERR_RETRIES 10
|
||||
|
||||
#define FSI_GPIO_CMD_DPOLL 0x2
|
||||
#define FSI_GPIO_CMD_EPOLL 0x3
|
||||
#define FSI_GPIO_CMD_TERM 0x3f
|
||||
#define FSI_GPIO_CMD_ABS_AR 0x4
|
||||
#define FSI_GPIO_CMD_REL_AR 0x5
|
||||
#define FSI_GPIO_CMD_SAME_AR 0x3 /* but only a 2-bit opcode... */
|
||||
|
||||
|
||||
#define FSI_GPIO_DPOLL_CLOCKS 50 /* < 21 will cause slave to hang */
|
||||
|
||||
/* Bus errors */
|
||||
#define FSI_GPIO_ERR_BUSY 1 /* Slave stuck in busy state */
|
||||
/* Slave responses */
|
||||
#define FSI_GPIO_RESP_ACK 0 /* Success */
|
||||
#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 */
|
||||
@ -330,6 +333,16 @@ static void build_dpoll_command(struct fsi_gpio_msg *cmd, uint8_t slave_id)
|
||||
msg_push_crc(cmd);
|
||||
}
|
||||
|
||||
static void build_epoll_command(struct fsi_gpio_msg *cmd, uint8_t slave_id)
|
||||
{
|
||||
cmd->bits = 0;
|
||||
cmd->msg = 0;
|
||||
|
||||
msg_push_bits(cmd, slave_id, 2);
|
||||
msg_push_bits(cmd, FSI_GPIO_CMD_EPOLL, 3);
|
||||
msg_push_crc(cmd);
|
||||
}
|
||||
|
||||
static void echo_delay(struct fsi_master_gpio *master)
|
||||
{
|
||||
set_sda_output(master, 1);
|
||||
@ -355,6 +368,12 @@ 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
|
||||
* for other situations. It will be converted to something else
|
||||
* higher up the stack before it reaches userspace.
|
||||
*/
|
||||
static int read_one_response(struct fsi_master_gpio *master,
|
||||
uint8_t data_size, struct fsi_gpio_msg *msgp, uint8_t *tagp)
|
||||
{
|
||||
@ -379,7 +398,7 @@ static int read_one_response(struct fsi_master_gpio *master,
|
||||
"Master time out waiting for response\n");
|
||||
fsi_master_gpio_error(master, FSI_GPIO_MTOE);
|
||||
spin_unlock_irqrestore(&master->bit_lock, flags);
|
||||
return -EIO;
|
||||
return -ETIMEDOUT;
|
||||
}
|
||||
|
||||
msg.bits = 0;
|
||||
@ -405,7 +424,7 @@ static int read_one_response(struct fsi_master_gpio *master,
|
||||
if (crc) {
|
||||
dev_dbg(master->dev, "ERR response CRC\n");
|
||||
fsi_master_gpio_error(master, FSI_GPIO_CRC_INVAL);
|
||||
return -EIO;
|
||||
return -EAGAIN;
|
||||
}
|
||||
|
||||
if (msgp)
|
||||
@ -451,11 +470,33 @@ static int poll_for_response(struct fsi_master_gpio *master,
|
||||
unsigned long flags;
|
||||
uint8_t tag;
|
||||
uint8_t *data_byte = data;
|
||||
|
||||
int crc_err_retries = 0;
|
||||
retry:
|
||||
rc = read_one_response(master, size, &response, &tag);
|
||||
if (rc)
|
||||
return rc;
|
||||
|
||||
/* Handle retries on CRC errors */
|
||||
if (rc == -EAGAIN) {
|
||||
/* Too many retries ? */
|
||||
if (crc_err_retries++ > FSI_CRC_ERR_RETRIES) {
|
||||
/*
|
||||
* Pass it up as a -EIO otherwise upper level will retry
|
||||
* the whole command which isn't what we want here.
|
||||
*/
|
||||
rc = -EIO;
|
||||
goto fail;
|
||||
}
|
||||
dev_dbg(master->dev,
|
||||
"CRC error retry %d\n", crc_err_retries);
|
||||
trace_fsi_master_gpio_crc_rsp_error(master);
|
||||
build_epoll_command(&cmd, slave);
|
||||
spin_lock_irqsave(&master->bit_lock, flags);
|
||||
clock_zeros(master, FSI_GPIO_EPOLL_CLOCKS);
|
||||
serial_out(master, &cmd);
|
||||
echo_delay(master);
|
||||
spin_unlock_irqrestore(&master->bit_lock, flags);
|
||||
goto retry;
|
||||
} else if (rc)
|
||||
goto fail;
|
||||
|
||||
switch (tag) {
|
||||
case FSI_GPIO_RESP_ACK:
|
||||
@ -496,18 +537,21 @@ static int poll_for_response(struct fsi_master_gpio *master,
|
||||
break;
|
||||
|
||||
case FSI_GPIO_RESP_ERRA:
|
||||
case FSI_GPIO_RESP_ERRC:
|
||||
dev_dbg(master->dev, "ERR%c received: 0x%x\n",
|
||||
tag == FSI_GPIO_RESP_ERRA ? 'A' : 'C',
|
||||
(int)response.msg);
|
||||
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;
|
||||
}
|
||||
|
||||
if (busy_count > 0)
|
||||
trace_fsi_master_gpio_poll_response_busy(master, busy_count);
|
||||
|
||||
fail:
|
||||
/* Clock the slave enough to be ready for next operation */
|
||||
spin_lock_irqsave(&master->bit_lock, flags);
|
||||
clock_zeros(master, FSI_GPIO_PRIME_SLAVE_CLOCKS);
|
||||
@ -536,11 +580,21 @@ static int send_request(struct fsi_master_gpio *master,
|
||||
static int fsi_master_gpio_xfer(struct fsi_master_gpio *master, uint8_t slave,
|
||||
struct fsi_gpio_msg *cmd, size_t resp_len, void *resp)
|
||||
{
|
||||
int rc;
|
||||
int rc = -EAGAIN, retries = 0;
|
||||
|
||||
rc = send_request(master, cmd);
|
||||
if (!rc)
|
||||
while ((retries++) < FSI_CRC_ERR_RETRIES) {
|
||||
rc = send_request(master, cmd);
|
||||
if (rc)
|
||||
break;
|
||||
rc = poll_for_response(master, slave, resp_len, resp);
|
||||
if (rc != -EAGAIN)
|
||||
break;
|
||||
rc = -EIO;
|
||||
dev_warn(master->dev, "ECRC retry %d\n", retries);
|
||||
|
||||
/* Pace it a bit before retry */
|
||||
msleep(1);
|
||||
}
|
||||
|
||||
return rc;
|
||||
}
|
||||
|
||||
@ -64,6 +64,33 @@ TRACE_EVENT(fsi_master_gpio_break,
|
||||
)
|
||||
);
|
||||
|
||||
TRACE_EVENT(fsi_master_gpio_crc_cmd_error,
|
||||
TP_PROTO(const struct fsi_master_gpio *master),
|
||||
TP_ARGS(master),
|
||||
TP_STRUCT__entry(
|
||||
__field(int, master_idx)
|
||||
),
|
||||
TP_fast_assign(
|
||||
__entry->master_idx = master->master.idx;
|
||||
),
|
||||
TP_printk("fsi-gpio%d ----CRC command retry---",
|
||||
__entry->master_idx
|
||||
)
|
||||
);
|
||||
|
||||
TRACE_EVENT(fsi_master_gpio_crc_rsp_error,
|
||||
TP_PROTO(const struct fsi_master_gpio *master),
|
||||
TP_ARGS(master),
|
||||
TP_STRUCT__entry(
|
||||
__field(int, master_idx)
|
||||
),
|
||||
TP_fast_assign(
|
||||
__entry->master_idx = master->master.idx;
|
||||
),
|
||||
TP_printk("fsi-gpio%d ----CRC response---",
|
||||
__entry->master_idx
|
||||
)
|
||||
);
|
||||
|
||||
TRACE_EVENT(fsi_master_gpio_poll_response_busy,
|
||||
TP_PROTO(const struct fsi_master_gpio *master, int busy),
|
||||
|
||||
Loading…
Reference in New Issue
Block a user