From c24b8d574b7c6f9cc2c50ed1e674f4333cc53736 Mon Sep 17 00:00:00 2001 From: Shreesha Rajashekar Date: Tue, 2 Apr 2019 18:18:22 -0700 Subject: [PATCH] i2c: iproc: Extend I2C read up to 255 bytes Add support to allow I2C master read transfer up to 255 bytes. Signed-off-by: Shreesha Rajashekar Signed-off-by: Rayagonda Kokatanur Signed-off-by: Ray Jui Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-bcm-iproc.c | 96 +++++++++++++++++++++++++++++--------- 1 file changed, 74 insertions(+), 22 deletions(-) diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c index 4c8c3bc4669c..4c31f4e178b6 100644 --- a/drivers/i2c/busses/i2c-bcm-iproc.c +++ b/drivers/i2c/busses/i2c-bcm-iproc.c @@ -80,6 +80,10 @@ #define I2C_TIMEOUT_MSEC 50000 #define M_TX_RX_FIFO_SIZE 64 +#define M_RX_FIFO_MAX_THLD_VALUE (M_TX_RX_FIFO_SIZE - 1) + +#define M_RX_MAX_READ_LEN 255 +#define M_RX_FIFO_THLD_VALUE 50 enum bus_speed_index { I2C_SPD_100K = 0, @@ -102,17 +106,39 @@ struct bcm_iproc_i2c_dev { /* bytes that have been transferred */ unsigned int tx_bytes; + /* bytes that have been read */ + unsigned int rx_bytes; + unsigned int thld_bytes; }; /* * Can be expanded in the future if more interrupt status bits are utilized */ -#define ISR_MASK (BIT(IS_M_START_BUSY_SHIFT) | BIT(IS_M_TX_UNDERRUN_SHIFT)) +#define ISR_MASK (BIT(IS_M_START_BUSY_SHIFT) | BIT(IS_M_TX_UNDERRUN_SHIFT)\ + | BIT(IS_M_RX_THLD_SHIFT)) + +static void bcm_iproc_i2c_read_valid_bytes(struct bcm_iproc_i2c_dev *iproc_i2c) +{ + struct i2c_msg *msg = iproc_i2c->msg; + + /* Read valid data from RX FIFO */ + while (iproc_i2c->rx_bytes < msg->len) { + if (!((readl(iproc_i2c->base + M_FIFO_CTRL_OFFSET) >> M_FIFO_RX_CNT_SHIFT) + & M_FIFO_RX_CNT_MASK)) + break; + + msg->buf[iproc_i2c->rx_bytes] = + (readl(iproc_i2c->base + M_RX_OFFSET) >> + M_RX_DATA_SHIFT) & M_RX_DATA_MASK; + iproc_i2c->rx_bytes++; + } +} static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data) { struct bcm_iproc_i2c_dev *iproc_i2c = data; u32 status = readl(iproc_i2c->base + IS_OFFSET); + u32 tmp; status &= ISR_MASK; @@ -136,8 +162,6 @@ static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data) /* mark the last byte */ if (idx == msg->len - 1) { - u32 tmp; - val |= BIT(M_TX_WR_STATUS_SHIFT); /* @@ -156,6 +180,32 @@ static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data) iproc_i2c->tx_bytes += tx_bytes; } + if (status & BIT(IS_M_RX_THLD_SHIFT)) { + struct i2c_msg *msg = iproc_i2c->msg; + u32 bytes_left; + + bcm_iproc_i2c_read_valid_bytes(iproc_i2c); + bytes_left = msg->len - iproc_i2c->rx_bytes; + if (bytes_left == 0) { + /* finished reading all data, disable rx thld event */ + tmp = readl(iproc_i2c->base + IE_OFFSET); + tmp &= ~BIT(IS_M_RX_THLD_SHIFT); + writel(tmp, iproc_i2c->base + IE_OFFSET); + } else if (bytes_left < iproc_i2c->thld_bytes) { + /* set bytes left as threshold */ + tmp = readl(iproc_i2c->base + M_FIFO_CTRL_OFFSET); + tmp &= ~(M_FIFO_RX_THLD_MASK << M_FIFO_RX_THLD_SHIFT); + tmp |= (bytes_left << M_FIFO_RX_THLD_SHIFT); + writel(tmp, iproc_i2c->base + M_FIFO_CTRL_OFFSET); + iproc_i2c->thld_bytes = bytes_left; + } + /* + * bytes_left >= iproc_i2c->thld_bytes, + * hence no need to change the THRESHOLD SET. + * It will remain as iproc_i2c->thld_bytes itself + */ + } + if (status & BIT(IS_M_START_BUSY_SHIFT)) { iproc_i2c->xfer_is_done = 1; complete(&iproc_i2c->done); @@ -253,7 +303,7 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c, { int ret, i; u8 addr; - u32 val; + u32 val, tmp, val_intr_en; unsigned int tx_bytes; unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT_MSEC); @@ -298,7 +348,7 @@ 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. */ - val = BIT(IE_M_START_BUSY_SHIFT); + val_intr_en = BIT(IE_M_START_BUSY_SHIFT); /* * If TX data size is larger than the TX FIFO, need to enable TX @@ -307,9 +357,7 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c, */ 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); + val_intr_en |= BIT(IE_M_TX_UNDERRUN_SHIFT); /* * Now we can activate the transfer. For a read operation, specify the @@ -317,11 +365,27 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c, */ val = BIT(M_CMD_START_BUSY_SHIFT); if (msg->flags & I2C_M_RD) { + iproc_i2c->rx_bytes = 0; + if (msg->len > M_RX_FIFO_MAX_THLD_VALUE) + iproc_i2c->thld_bytes = M_RX_FIFO_THLD_VALUE; + else + iproc_i2c->thld_bytes = msg->len; + + /* set threshold value */ + tmp = readl(iproc_i2c->base + M_FIFO_CTRL_OFFSET); + tmp &= ~(M_FIFO_RX_THLD_MASK << M_FIFO_RX_THLD_SHIFT); + tmp |= iproc_i2c->thld_bytes << M_FIFO_RX_THLD_SHIFT; + writel(tmp, iproc_i2c->base + M_FIFO_CTRL_OFFSET); + + /* enable the RX threshold interrupt */ + val_intr_en |= BIT(IE_M_RX_THLD_SHIFT); + val |= (M_CMD_PROTOCOL_BLK_RD << M_CMD_PROTOCOL_SHIFT) | (msg->len << M_CMD_RD_CNT_SHIFT); } else { val |= (M_CMD_PROTOCOL_BLK_WR << M_CMD_PROTOCOL_SHIFT); } + writel(val_intr_en, iproc_i2c->base + IE_OFFSET); writel(val, iproc_i2c->base + M_CMD_OFFSET); time_left = wait_for_completion_timeout(&iproc_i2c->done, time_left); @@ -353,17 +417,6 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c, return ret; } - /* - * For a read operation, we now need to load the data from FIFO - * into the memory buffer - */ - if (msg->flags & I2C_M_RD) { - for (i = 0; i < msg->len; i++) { - msg->buf[i] = (readl(iproc_i2c->base + M_RX_OFFSET) >> - M_RX_DATA_SHIFT) & M_RX_DATA_MASK; - } - } - return 0; } @@ -395,9 +448,8 @@ static const struct i2c_algorithm bcm_iproc_algo = { .functionality = bcm_iproc_i2c_functionality, }; -static const 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, +static struct i2c_adapter_quirks bcm_iproc_i2c_quirks = { + .max_read_len = M_RX_MAX_READ_LEN, }; static int bcm_iproc_i2c_cfg_speed(struct bcm_iproc_i2c_dev *iproc_i2c) -- 2.11.0