diff options
Diffstat (limited to 'drivers/fsi/fsi-master-gpio.c')
| -rw-r--r-- | drivers/fsi/fsi-master-gpio.c | 90 |
1 files changed, 72 insertions, 18 deletions
diff --git a/drivers/fsi/fsi-master-gpio.c b/drivers/fsi/fsi-master-gpio.c index 0a6799bda294..351c12f2ac55 100644 --- a/drivers/fsi/fsi-master-gpio.c +++ b/drivers/fsi/fsi-master-gpio.c @@ -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 @@ retry: 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; } |