diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-cadence.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-cadence.c | 207 |
1 files changed, 192 insertions, 15 deletions
diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c index e689448d229f..ee2f32cd54ce 100644 --- a/drivers/i2c/busses/i2c-cadence.c +++ b/drivers/i2c/busses/i2c-cadence.c @@ -129,6 +129,7 @@ #define CDNS_I2C_BROKEN_HOLD_BIT BIT(0) #define CDNS_I2C_POLL_US 100000 +#define CDNS_I2C_POLL_US_ATOMIC 10 #define CDNS_I2C_TIMEOUT_US 500000 #define cdns_i2c_readreg(offset) readl_relaxed(id->membase + offset) @@ -189,6 +190,8 @@ enum cdns_i2c_slave_state { * @slave_state: I2C Slave state(idle/read/write). * @fifo_depth: The depth of the transfer FIFO * @transfer_size: The maximum number of bytes in one transfer + * @atomic: Mode of transfer + * @err_status_atomic: Error status in atomic mode */ struct cdns_i2c { struct device *dev; @@ -219,6 +222,8 @@ struct cdns_i2c { #endif u32 fifo_depth; unsigned int transfer_size; + bool atomic; + int err_status_atomic; }; struct cdns_platform_data { @@ -256,7 +261,7 @@ static void cdns_i2c_init(struct cdns_i2c *id) * * Return: 0 always */ -static int __maybe_unused cdns_i2c_runtime_suspend(struct device *dev) +static int cdns_i2c_runtime_suspend(struct device *dev) { struct cdns_i2c *xi2c = dev_get_drvdata(dev); @@ -273,7 +278,7 @@ static int __maybe_unused cdns_i2c_runtime_suspend(struct device *dev) * * Return: 0 on success and error value on error */ -static int __maybe_unused cdns_i2c_runtime_resume(struct device *dev) +static int cdns_i2c_runtime_resume(struct device *dev) { struct cdns_i2c *xi2c = dev_get_drvdata(dev); int ret; @@ -621,6 +626,89 @@ static irqreturn_t cdns_i2c_isr(int irq, void *ptr) return cdns_i2c_master_isr(ptr); } +static bool cdns_i2c_error_check(struct cdns_i2c *id) +{ + unsigned int isr_status; + + id->err_status = 0; + + isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET); + cdns_i2c_writereg(isr_status & CDNS_I2C_IXR_ERR_INTR_MASK, CDNS_I2C_ISR_OFFSET); + + id->err_status = isr_status & CDNS_I2C_IXR_ERR_INTR_MASK; + + return !!id->err_status; +} + +static void cdns_i2c_mrecv_atomic(struct cdns_i2c *id) +{ + while (id->recv_count > 0) { + bool updatetx; + + /* + * Check if transfer size register needs to be updated again for a + * large data receive operation. + */ + updatetx = id->recv_count > id->curr_recv_count; + + while (id->curr_recv_count > 0) { + if (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) & CDNS_I2C_SR_RXDV) { + *id->p_recv_buf = cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET); + id->p_recv_buf++; + id->recv_count--; + id->curr_recv_count--; + + /* + * Clear the hold bit that was set for FIFO control, + * if the remaining RX data is less than or equal to + * the FIFO depth, unless a repeated start is selected. + */ + if (id->recv_count <= id->fifo_depth && !id->bus_hold_flag) + cdns_i2c_clear_bus_hold(id); + } + if (cdns_i2c_error_check(id)) + return; + if (cdns_is_holdquirk(id, updatetx)) + break; + } + + /* + * The controller sends NACK to the slave/target when transfer size + * register reaches zero without considering the HOLD bit. + * This workaround is implemented for large data transfers to + * maintain transfer size non-zero while performing a large + * receive operation. + */ + if (cdns_is_holdquirk(id, updatetx)) { + /* wait while fifo is full */ + while (cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET) != + (id->curr_recv_count - id->fifo_depth)) + ; + + /* + * Check number of bytes to be received against maximum + * transfer size and update register accordingly. + */ + if ((id->recv_count - id->fifo_depth) > + id->transfer_size) { + cdns_i2c_writereg(id->transfer_size, + CDNS_I2C_XFER_SIZE_OFFSET); + id->curr_recv_count = id->transfer_size + + id->fifo_depth; + } else { + cdns_i2c_writereg(id->recv_count - + id->fifo_depth, + CDNS_I2C_XFER_SIZE_OFFSET); + id->curr_recv_count = id->recv_count; + } + } + } + + /* Clear hold (if not repeated start) */ + if (!id->recv_count && !id->bus_hold_flag) + cdns_i2c_clear_bus_hold(id); +} + /** * cdns_i2c_mrecv - Prepare and start a master receive operation * @id: pointer to the i2c device structure @@ -715,7 +803,34 @@ static void cdns_i2c_mrecv(struct cdns_i2c *id) cdns_i2c_writereg(addr, CDNS_I2C_ADDR_OFFSET); } - cdns_i2c_writereg(CDNS_I2C_ENABLED_INTR_MASK, CDNS_I2C_IER_OFFSET); + if (!id->atomic) + cdns_i2c_writereg(CDNS_I2C_ENABLED_INTR_MASK, CDNS_I2C_IER_OFFSET); + else + cdns_i2c_mrecv_atomic(id); +} + +static void cdns_i2c_msend_rem_atomic(struct cdns_i2c *id) +{ + while (id->send_count) { + unsigned int avail_bytes; + unsigned int bytes_to_send; + + avail_bytes = id->fifo_depth - cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET); + if (id->send_count > avail_bytes) + bytes_to_send = avail_bytes; + else + bytes_to_send = id->send_count; + + while (bytes_to_send--) { + cdns_i2c_writereg((*id->p_send_buf++), CDNS_I2C_DATA_OFFSET); + id->send_count--; + } + if (cdns_i2c_error_check(id)) + return; + } + + if (!id->send_count && !id->bus_hold_flag) + cdns_i2c_clear_bus_hold(id); } /** @@ -778,7 +893,10 @@ static void cdns_i2c_msend(struct cdns_i2c *id) cdns_i2c_writereg(id->p_msg->addr & CDNS_I2C_ADDR_MASK, CDNS_I2C_ADDR_OFFSET); - cdns_i2c_writereg(CDNS_I2C_ENABLED_INTR_MASK, CDNS_I2C_IER_OFFSET); + if (!id->atomic) + cdns_i2c_writereg(CDNS_I2C_ENABLED_INTR_MASK, CDNS_I2C_IER_OFFSET); + else if (id->send_count > 0) + cdns_i2c_msend_rem_atomic(id); } /** @@ -818,7 +936,8 @@ static int cdns_i2c_process_msg(struct cdns_i2c *id, struct i2c_msg *msg, id->p_msg = msg; id->err_status = 0; - reinit_completion(&id->xfer_done); + if (!id->atomic) + reinit_completion(&id->xfer_done); /* Check for the TEN Bit mode on each msg */ reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET); @@ -840,14 +959,31 @@ static int cdns_i2c_process_msg(struct cdns_i2c *id, struct i2c_msg *msg, /* Minimal time to execute this message */ msg_timeout = msecs_to_jiffies((1000 * msg->len * BITS_PER_BYTE) / id->i2c_clk); - /* Plus some wiggle room */ - msg_timeout += msecs_to_jiffies(500); + + /* + * Plus some wiggle room. + * For non-atomic contexts, 500 ms is added to the timeout. + * For atomic contexts, 2000 ms is added because transfers happen in polled + * mode, requiring more time to account for the polling overhead. + */ + if (!id->atomic) + msg_timeout += msecs_to_jiffies(500); + else + msg_timeout += msecs_to_jiffies(2000); if (msg_timeout < adap->timeout) msg_timeout = adap->timeout; - /* Wait for the signal of completion */ - time_left = wait_for_completion_timeout(&id->xfer_done, msg_timeout); + if (!id->atomic) { + /* Wait for the signal of completion */ + time_left = wait_for_completion_timeout(&id->xfer_done, msg_timeout); + } else { + /* 0 is success, -ETIMEDOUT is error */ + time_left = !readl_poll_timeout_atomic(id->membase + CDNS_I2C_ISR_OFFSET, + reg, (reg & CDNS_I2C_IXR_COMP), + CDNS_I2C_POLL_US_ATOMIC, msg_timeout); + } + if (time_left == 0) { cdns_i2c_master_reset(adap); return -ETIMEDOUT; @@ -876,11 +1012,16 @@ static int cdns_i2c_master_common_xfer(struct i2c_adapter *adap, bool hold_quirk; /* Check if the bus is free */ - - ret = readl_relaxed_poll_timeout(id->membase + CDNS_I2C_SR_OFFSET, - reg, - !(reg & CDNS_I2C_SR_BA), - CDNS_I2C_POLL_US, CDNS_I2C_TIMEOUT_US); + if (!id->atomic) + ret = readl_relaxed_poll_timeout(id->membase + CDNS_I2C_SR_OFFSET, + reg, + !(reg & CDNS_I2C_SR_BA), + CDNS_I2C_POLL_US, CDNS_I2C_TIMEOUT_US); + else + ret = readl_poll_timeout_atomic(id->membase + CDNS_I2C_SR_OFFSET, + reg, + !(reg & CDNS_I2C_SR_BA), + CDNS_I2C_POLL_US_ATOMIC, CDNS_I2C_TIMEOUT_US); if (ret) { ret = -EAGAIN; if (id->adap.bus_recovery_info) @@ -926,7 +1067,7 @@ static int cdns_i2c_master_common_xfer(struct i2c_adapter *adap, return ret; /* Report the other error interrupts to application */ - if (id->err_status) { + if (id->err_status || id->err_status_atomic) { cdns_i2c_master_reset(adap); if (id->err_status & CDNS_I2C_IXR_NACK) @@ -993,6 +1134,41 @@ out: } /** + * cdns_i2c_master_xfer_atomic - The i2c transfer function in atomic mode + * @adap: pointer to the i2c adapter driver instance + * @msgs: pointer to the i2c message structure + * @num: the number of messages to transfer + * + * Return: number of msgs processed on success, negative error otherwise + */ +static int cdns_i2c_master_xfer_atomic(struct i2c_adapter *adap, struct i2c_msg *msgs, + int num) +{ + int ret; + struct cdns_i2c *id = adap->algo_data; + + ret = cdns_i2c_runtime_resume(id->dev); + if (ret) + return ret; + + if (id->quirks & CDNS_I2C_BROKEN_HOLD_BIT) { + dev_warn(id->adap.dev.parent, + "Atomic xfer not supported for version 1.0\n"); + return 0; + } + + id->atomic = true; + ret = cdns_i2c_master_common_xfer(adap, msgs, num); + if (!ret) + ret = num; + + id->atomic = false; + cdns_i2c_runtime_suspend(id->dev); + + return ret; +} + +/** * cdns_i2c_func - Returns the supported features of the I2C driver * @adap: pointer to the i2c adapter structure * @@ -1056,6 +1232,7 @@ static int cdns_unreg_slave(struct i2c_client *slave) static const struct i2c_algorithm cdns_i2c_algo = { .master_xfer = cdns_i2c_master_xfer, + .master_xfer_atomic = cdns_i2c_master_xfer_atomic, .functionality = cdns_i2c_func, #if IS_ENABLED(CONFIG_I2C_SLAVE) .reg_slave = cdns_reg_slave, |