diff options
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-bcm-iproc.c | 84 |
1 files changed, 75 insertions, 9 deletions
diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c index 859a623..b9f0fff 100644 --- a/drivers/i2c/busses/i2c-bcm-iproc.c +++ b/drivers/i2c/busses/i2c-bcm-iproc.c @@ -58,11 +58,13 @@ #define IE_M_RX_FIFO_FULL_SHIFT 31 #define IE_M_RX_THLD_SHIFT 30 #define IE_M_START_BUSY_SHIFT 28 +#define IE_M_TX_UNDERRUN_SHIFT 27 #define IS_OFFSET 0x3c #define IS_M_RX_FIFO_FULL_SHIFT 31 #define IS_M_RX_THLD_SHIFT 30 #define IS_M_START_BUSY_SHIFT 28 +#define IS_M_TX_UNDERRUN_SHIFT 27 #define M_TX_OFFSET 0x40 #define M_TX_WR_STATUS_SHIFT 31 @@ -76,7 +78,7 @@ #define M_RX_DATA_SHIFT 0 #define M_RX_DATA_MASK 0xff -#define I2C_TIMEOUT_MSEC 100 +#define I2C_TIMEOUT_MSEC 50000 #define M_TX_RX_FIFO_SIZE 64 enum bus_speed_index { @@ -95,12 +97,17 @@ struct bcm_iproc_i2c_dev { struct completion done; int xfer_is_done; + + struct i2c_msg *msg; + + /* bytes that have been transferred */ + unsigned int tx_bytes; }; /* * Can be expanded in the future if more interrupt status bits are utilized */ -#define ISR_MASK (1 << IS_M_START_BUSY_SHIFT) +#define ISR_MASK (BIT(IS_M_START_BUSY_SHIFT) | BIT(IS_M_TX_UNDERRUN_SHIFT)) static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data) { @@ -112,9 +119,49 @@ static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data) if (!status) return IRQ_NONE; + /* TX FIFO is empty and we have more data to send */ + if (status & BIT(IS_M_TX_UNDERRUN_SHIFT)) { + struct i2c_msg *msg = iproc_i2c->msg; + unsigned int tx_bytes = msg->len - iproc_i2c->tx_bytes; + unsigned int i; + u32 val; + + /* can only fill up to the FIFO size */ + tx_bytes = min_t(unsigned int, tx_bytes, M_TX_RX_FIFO_SIZE); + for (i = 0; i < tx_bytes; i++) { + /* start from where we left over */ + unsigned int idx = iproc_i2c->tx_bytes + i; + + val = msg->buf[idx]; + + /* mark the last byte */ + if (idx == msg->len - 1) { + u32 tmp; + + val |= BIT(M_TX_WR_STATUS_SHIFT); + + /* + * Since this is the last byte, we should + * now disable TX FIFO underrun interrupt + */ + tmp = readl(iproc_i2c->base + IE_OFFSET); + tmp &= ~BIT(IE_M_TX_UNDERRUN_SHIFT); + writel(tmp, iproc_i2c->base + IE_OFFSET); + } + + /* load data into TX FIFO */ + writel(val, iproc_i2c->base + M_TX_OFFSET); + } + /* update number of transferred bytes */ + iproc_i2c->tx_bytes += tx_bytes; + } + + if (status & BIT(IS_M_START_BUSY_SHIFT)) { + iproc_i2c->xfer_is_done = 1; + complete_all(&iproc_i2c->done); + } + writel(status, iproc_i2c->base + IS_OFFSET); - iproc_i2c->xfer_is_done = 1; - complete_all(&iproc_i2c->done); return IRQ_HANDLED; } @@ -207,6 +254,7 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c, int ret, i; u8 addr; u32 val; + unsigned int tx_bytes; unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT_MSEC); /* check if bus is busy */ @@ -216,13 +264,20 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c, return -EBUSY; } + iproc_i2c->msg = msg; + /* format and load slave address into the TX FIFO */ addr = msg->addr << 1 | (msg->flags & I2C_M_RD ? 1 : 0); writel(addr, iproc_i2c->base + M_TX_OFFSET); - /* for a write transaction, load data into the TX FIFO */ + /* + * For a write transaction, load data into the TX FIFO. Only allow + * loading up to TX FIFO size - 1 bytes of data since the first byte + * has been used up by the slave address + */ + tx_bytes = min_t(unsigned int, msg->len, M_TX_RX_FIFO_SIZE - 1); if (!(msg->flags & I2C_M_RD)) { - for (i = 0; i < msg->len; i++) { + for (i = 0; i < tx_bytes; i++) { val = msg->buf[i]; /* mark the last byte */ @@ -231,6 +286,7 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c, writel(val, iproc_i2c->base + M_TX_OFFSET); } + iproc_i2c->tx_bytes = tx_bytes; } /* mark as incomplete before starting the transaction */ @@ -242,13 +298,24 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c, * transaction is done, i.e., the internal start_busy bit, transitions * from 1 to 0. */ - writel(1 << IE_M_START_BUSY_SHIFT, iproc_i2c->base + IE_OFFSET); + val = BIT(IE_M_START_BUSY_SHIFT); + + /* + * If TX data size is larger than the TX FIFO, need to enable TX + * underrun interrupt, which will be triggerred when the TX FIFO is + * empty. When that happens we can then pump more data into the FIFO + */ + if (!(msg->flags & I2C_M_RD) && + msg->len > iproc_i2c->tx_bytes) + val |= BIT(IE_M_TX_UNDERRUN_SHIFT); + + writel(val, iproc_i2c->base + IE_OFFSET); /* * Now we can activate the transfer. For a read operation, specify the * number of bytes to read */ - val = 1 << M_CMD_START_BUSY_SHIFT; + val = BIT(M_CMD_START_BUSY_SHIFT); if (msg->flags & I2C_M_RD) { val |= (M_CMD_PROTOCOL_BLK_RD << M_CMD_PROTOCOL_SHIFT) | (msg->len << M_CMD_RD_CNT_SHIFT); @@ -331,7 +398,6 @@ static const struct i2c_algorithm bcm_iproc_algo = { static struct i2c_adapter_quirks bcm_iproc_i2c_quirks = { /* need to reserve one byte in the FIFO for the slave address */ .max_read_len = M_TX_RX_FIFO_SIZE - 1, - .max_write_len = M_TX_RX_FIFO_SIZE - 1, }; static int bcm_iproc_i2c_cfg_speed(struct bcm_iproc_i2c_dev *iproc_i2c) |
