Re: [PATCH v3 2/8] i2c: iproc: Add Slave mode support
From: Ray Jui
Date: Mon Jan 21 2019 - 02:17:57 EST
On 1/17/2019 10:04 PM, Rayagonda Kokatanur wrote:
> From: Shreesha Rajashekar <shreesha.rajashekar@xxxxxxxxxxxx>
>
> Add I2C slave mode support to the iProc I2C driver.
> I2C slave mode is supported in the iProc I2C block
> in all iProc based SoCs that include the I2C block.
>
> Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@xxxxxxxxxxxx>
> Signed-off-by: Shreesha Rajashekar <shreesha.rajashekar@xxxxxxxxxxxx>
> Signed-off-by: Michael Cheng <ccheng@xxxxxxxxxxxx>
> ---
> drivers/i2c/busses/Kconfig | 1 +
> drivers/i2c/busses/i2c-bcm-iproc.c | 315 ++++++++++++++++++++++++++++++++++++-
> 2 files changed, 310 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index f2c681971201..e0798b82b3bc 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -424,6 +424,7 @@ config I2C_BCM_IPROC
> tristate "Broadcom iProc I2C controller"
> depends on ARCH_BCM_IPROC || COMPILE_TEST
> default ARCH_BCM_IPROC
> + select I2C_SLAVE
> help
> If you say yes to this option, support will be included for the
> Broadcom iProc I2C controller.
> diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c
> index eb7339a0280e..4a4a052efcc9 100644
> --- a/drivers/i2c/busses/i2c-bcm-iproc.c
> +++ b/drivers/i2c/busses/i2c-bcm-iproc.c
> @@ -23,11 +23,30 @@
> #define CFG_OFFSET 0x00
> #define CFG_RESET_SHIFT 31
> #define CFG_EN_SHIFT 30
> +#define CFG_SLAVE_ADDR_0_SHIFT 28
> #define CFG_M_RETRY_CNT_SHIFT 16
> #define CFG_M_RETRY_CNT_MASK 0x0f
>
> #define TIM_CFG_OFFSET 0x04
> #define TIM_CFG_MODE_400_SHIFT 31
> +#define TIM_RAND_SLAVE_STRETCH_SHIFT 24
> +#define TIM_RAND_SLAVE_STRETCH_MASK 0x7f
> +#define TIM_PERIODIC_SLAVE_STRETCH_SHIFT 16
> +#define TIM_PERIODIC_SLAVE_STRETCH_MASK 0x7f
> +
> +#define S_CFG_SMBUS_ADDR_OFFSET 0x08
> +#define S_CFG_EN_NIC_SMB_ADDR3_SHIFT 31
> +#define S_CFG_NIC_SMB_ADDR3_SHIFT 24
> +#define S_CFG_NIC_SMB_ADDR3_MASK 0x7f
> +#define S_CFG_EN_NIC_SMB_ADDR2_SHIFT 23
> +#define S_CFG_NIC_SMB_ADDR2_SHIFT 16
> +#define S_CFG_NIC_SMB_ADDR2_MASK 0x7f
> +#define S_CFG_EN_NIC_SMB_ADDR1_SHIFT 15
> +#define S_CFG_NIC_SMB_ADDR1_SHIFT 8
> +#define S_CFG_NIC_SMB_ADDR1_MASK 0x7f
> +#define S_CFG_EN_NIC_SMB_ADDR0_SHIFT 7
> +#define S_CFG_NIC_SMB_ADDR0_SHIFT 0
> +#define S_CFG_NIC_SMB_ADDR0_MASK 0x7f
>
> #define M_FIFO_CTRL_OFFSET 0x0c
> #define M_FIFO_RX_FLUSH_SHIFT 31
> @@ -37,6 +56,14 @@
> #define M_FIFO_RX_THLD_SHIFT 8
> #define M_FIFO_RX_THLD_MASK 0x3f
>
> +#define S_FIFO_CTRL_OFFSET 0x10
> +#define S_FIFO_RX_FLUSH_SHIFT 31
> +#define S_FIFO_TX_FLUSH_SHIFT 30
> +#define S_FIFO_RX_CNT_SHIFT 16
> +#define S_FIFO_RX_CNT_MASK 0x7f
> +#define S_FIFO_RX_THLD_SHIFT 8
> +#define S_FIFO_RX_THLD_MASK 0x3f
> +
> #define M_CMD_OFFSET 0x30
> #define M_CMD_START_BUSY_SHIFT 31
> #define M_CMD_STATUS_SHIFT 25
> @@ -46,6 +73,8 @@
> #define M_CMD_STATUS_NACK_ADDR 0x2
> #define M_CMD_STATUS_NACK_DATA 0x3
> #define M_CMD_STATUS_TIMEOUT 0x4
> +#define M_CMD_STATUS_FIFO_UNDERRUN 0x5
> +#define M_CMD_STATUS_RX_FIFO_FULL 0x6
> #define M_CMD_PROTOCOL_SHIFT 9
> #define M_CMD_PROTOCOL_MASK 0xf
> #define M_CMD_PROTOCOL_BLK_WR 0x7
> @@ -54,17 +83,36 @@
> #define M_CMD_RD_CNT_SHIFT 0
> #define M_CMD_RD_CNT_MASK 0xff
>
> +#define S_CMD_OFFSET 0x34
> +#define S_CMD_START_BUSY_SHIFT 31
> +#define S_CMD_STATUS_SHIFT 23
> +#define S_CMD_STATUS_MASK 0x07
> +#define S_CMD_STATUS_SUCCESS 0x0
> +#define S_CMD_STATUS_TIMEOUT 0x5
> +
> #define IE_OFFSET 0x38
> #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 IE_S_RX_FIFO_FULL_SHIFT 26
> +#define IE_S_RX_THLD_SHIFT 25
> +#define IE_S_RX_EVENT_SHIFT 24
> +#define IE_S_START_BUSY_SHIFT 23
> +#define IE_S_TX_UNDERRUN_SHIFT 22
> +#define IE_S_RD_EVENT_SHIFT 21
>
> #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 IS_S_RX_FIFO_FULL_SHIFT 26
> +#define IS_S_RX_THLD_SHIFT 25
> +#define IS_S_RX_EVENT_SHIFT 24
> +#define IS_S_START_BUSY_SHIFT 23
> +#define IS_S_TX_UNDERRUN_SHIFT 22
> +#define IS_S_RD_EVENT_SHIFT 21
>
> #define M_TX_OFFSET 0x40
> #define M_TX_WR_STATUS_SHIFT 31
> @@ -78,6 +126,18 @@
> #define M_RX_DATA_SHIFT 0
> #define M_RX_DATA_MASK 0xff
>
> +#define S_TX_OFFSET 0x48
> +#define S_TX_WR_STATUS_SHIFT 31
> +#define S_TX_DATA_SHIFT 0
> +#define S_TX_DATA_MASK 0xff
> +
> +#define S_RX_OFFSET 0x4c
> +#define S_RX_STATUS_SHIFT 30
> +#define S_RX_STATUS_MASK 0x03
> +#define S_RX_PEC_ERR_SHIFT 29
> +#define S_RX_DATA_SHIFT 0
> +#define S_RX_DATA_MASK 0xff
> +
> #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)
> @@ -85,6 +145,30 @@
> #define M_RX_MAX_READ_LEN 255
> #define M_RX_FIFO_THLD_VALUE 50
>
> +#define IE_M_ALL_INTERRUPT_SHIFT 27
> +#define IE_M_ALL_INTERRUPT_MASK 0x1e
> +
> +#define SLAVE_READ_WRITE_BIT_MASK 0x1
> +#define SLAVE_READ_WRITE_BIT_SHIFT 0x1
> +#define SLAVE_MAX_SIZE_TRANSACTION 64
> +#define SLAVE_CLOCK_STRETCH_TIME 25
> +
> +#define IE_S_ALL_INTERRUPT_SHIFT 21
> +#define IE_S_ALL_INTERRUPT_MASK 0x3f
> +
> +enum i2c_slave_read_status {
> + I2C_SLAVE_RX_FIFO_EMPTY = 0,
> + I2C_SLAVE_RX_START,
> + I2C_SLAVE_RX_DATA,
> + I2C_SLAVE_RX_END,
> +};
> +
> +enum i2c_slave_xfer_dir {
> + I2C_SLAVE_DIR_READ = 0,
> + I2C_SLAVE_DIR_WRITE,
> + I2C_SLAVE_DIR_NONE,
> +};
> +
> enum bus_speed_index {
> I2C_SPD_100K = 0,
> I2C_SPD_400K,
> @@ -104,6 +188,9 @@ struct bcm_iproc_i2c_dev {
>
> struct i2c_msg *msg;
>
> + struct i2c_client *slave;
> + enum i2c_slave_xfer_dir xfer_dir;
> +
> /* bytes that have been transferred */
> unsigned int tx_bytes;
> /* bytes that have been read */
> @@ -117,6 +204,157 @@ struct bcm_iproc_i2c_dev {
> #define ISR_MASK (BIT(IS_M_START_BUSY_SHIFT) | BIT(IS_M_TX_UNDERRUN_SHIFT)\
> | BIT(IS_M_RX_THLD_SHIFT))
>
> +#define ISR_MASK_SLAVE (BIT(IS_S_START_BUSY_SHIFT)\
> + | BIT(IS_S_RX_EVENT_SHIFT) | BIT(IS_S_RD_EVENT_SHIFT))
> +
> +static int bcm_iproc_i2c_reg_slave(struct i2c_client *slave);
> +static int bcm_iproc_i2c_unreg_slave(struct i2c_client *slave);
> +static void bcm_iproc_i2c_enable_disable(struct bcm_iproc_i2c_dev *iproc_i2c,
> + bool enable);
> +
> +static void bcm_iproc_i2c_slave_init(
> + struct bcm_iproc_i2c_dev *iproc_i2c, bool need_reset)
> +{
> + u32 val;
> +
> + if (need_reset) {
> + /* put controller in reset */
> + val = readl(iproc_i2c->base + CFG_OFFSET);
> + val |= BIT(CFG_RESET_SHIFT);
> + val &= ~(BIT(CFG_RESET_SHIFT));
> + writel(val, iproc_i2c->base + CFG_OFFSET);
> +
> + /* wait 100 usec per spec */
> + udelay(100);
> +
> + /* bring controller out of reset */
> + val &= ~(BIT(CFG_RESET_SHIFT));
> + writel(val, iproc_i2c->base + CFG_OFFSET);
> + }
> +
> + /* flush TX/RX FIFOs */
> + val = (BIT(S_FIFO_RX_FLUSH_SHIFT) | BIT(S_FIFO_TX_FLUSH_SHIFT));
> + writel(val, iproc_i2c->base + S_FIFO_CTRL_OFFSET);
> +
> + /* RANDOM SLAVE STRETCH time - 20ms*/
> + val = readl(iproc_i2c->base + TIM_CFG_OFFSET);
> + val &= ~(TIM_RAND_SLAVE_STRETCH_MASK << TIM_RAND_SLAVE_STRETCH_SHIFT);
> + val |= (SLAVE_CLOCK_STRETCH_TIME << TIM_RAND_SLAVE_STRETCH_SHIFT);
> + writel(val, iproc_i2c->base + TIM_CFG_OFFSET);
> +
> + /* Configure the slave address */
> + val = readl(iproc_i2c->base + S_CFG_SMBUS_ADDR_OFFSET);
> + val |= BIT(S_CFG_EN_NIC_SMB_ADDR3_SHIFT);
> + val &= ~(S_CFG_NIC_SMB_ADDR3_MASK << S_CFG_NIC_SMB_ADDR3_SHIFT);
> + val |= (iproc_i2c->slave->addr << S_CFG_NIC_SMB_ADDR3_SHIFT);
> + writel(val, iproc_i2c->base + S_CFG_SMBUS_ADDR_OFFSET);
> +
> + /* clear all pending slave interrupts */
> + writel(ISR_MASK_SLAVE, iproc_i2c->base + IS_OFFSET);
> +
> + /* Enable interrupt register for any READ event */
> + val = BIT(IE_S_RD_EVENT_SHIFT);
> + /* Enable interrupt register to indicate a valid byte in receive fifo */
> + val |= BIT(IE_S_RX_EVENT_SHIFT);
> + /* Enable interrupt register for the Slave BUSY command */
> + val |= BIT(IE_S_START_BUSY_SHIFT);
> + writel(val, iproc_i2c->base + IE_OFFSET);
> +
> + iproc_i2c->xfer_dir = I2C_SLAVE_DIR_NONE;
> +}
> +
> +static void bcm_iproc_i2c_check_slave_status(
> + struct bcm_iproc_i2c_dev *iproc_i2c)
> +{
> + u32 val;
> +
> + val = readl(iproc_i2c->base + S_CMD_OFFSET);
> + val = (val >> S_CMD_STATUS_SHIFT) & S_CMD_STATUS_MASK;
> +
> + if (val == S_CMD_STATUS_TIMEOUT) {
> + dev_err(iproc_i2c->device, "slave random stretch time timeout\n");
> +
> + /* re-initialize i2c for recovery */
> + bcm_iproc_i2c_enable_disable(iproc_i2c, false);
> + bcm_iproc_i2c_slave_init(iproc_i2c, true);
> + bcm_iproc_i2c_enable_disable(iproc_i2c, true);
> + }
> +}
> +
> +static bool bcm_iproc_i2c_slave_isr(struct bcm_iproc_i2c_dev *iproc_i2c,
> + u32 status)
> +{
> + u8 value;
> + u32 val;
> + u32 rd_status;
> + u32 tmp;
> +
> + /* Start of transaction. check address and populate the direction */
> + if (iproc_i2c->xfer_dir == I2C_SLAVE_DIR_NONE) {
> + tmp = readl(iproc_i2c->base + S_RX_OFFSET);
> + rd_status = (tmp >> S_RX_STATUS_SHIFT) & S_RX_STATUS_MASK;
> + /* This condition checks whether the request is a new request */
> + if (((rd_status == I2C_SLAVE_RX_START) &&
> + (status & BIT(IS_S_RX_EVENT_SHIFT))) ||
> + ((rd_status == I2C_SLAVE_RX_END) &&
> + (status & BIT(IS_S_RD_EVENT_SHIFT)))) {
> +
> + /* Last bit is W/R bit.
> + * If 1 then its a read request(by master).
> + */
> + iproc_i2c->xfer_dir = tmp & SLAVE_READ_WRITE_BIT_MASK;
> + if (iproc_i2c->xfer_dir == I2C_SLAVE_DIR_WRITE)
> + i2c_slave_event(iproc_i2c->slave,
> + I2C_SLAVE_READ_REQUESTED, &value);
> + else
> + i2c_slave_event(iproc_i2c->slave,
> + I2C_SLAVE_WRITE_REQUESTED, &value);
> + }
> + }
> +
> + /* read request from master */
> + if ((status & BIT(IS_S_RD_EVENT_SHIFT)) &&
> + (iproc_i2c->xfer_dir == I2C_SLAVE_DIR_WRITE)) {
> + i2c_slave_event(iproc_i2c->slave,
> + I2C_SLAVE_READ_PROCESSED, &value);
> + writel(value, iproc_i2c->base + S_TX_OFFSET);
> +
> + val = BIT(S_CMD_START_BUSY_SHIFT);
> + writel(val, iproc_i2c->base + S_CMD_OFFSET);
> + }
> +
> + /* write request from master */
> + if ((status & BIT(IS_S_RX_EVENT_SHIFT)) &&
> + (iproc_i2c->xfer_dir == I2C_SLAVE_DIR_READ)) {
> + val = readl(iproc_i2c->base + S_RX_OFFSET);
> + /* Its a write request by Master to Slave.
> + * We read data present in receive FIFO
> + */
> + value = (u8)((val >> S_RX_DATA_SHIFT) & S_RX_DATA_MASK);
> + i2c_slave_event(iproc_i2c->slave,
> + I2C_SLAVE_WRITE_RECEIVED, &value);
> +
> + /* check the status for the last byte of the transaction */
> + rd_status = (val >> S_RX_STATUS_SHIFT) & S_RX_STATUS_MASK;
> + if (rd_status == I2C_SLAVE_RX_END)
> + iproc_i2c->xfer_dir = I2C_SLAVE_DIR_NONE;
> +
> + dev_dbg(iproc_i2c->device, "\nread value = 0x%x\n", value);
> + }
> +
> + /* Stop */
> + if (status & BIT(IS_S_START_BUSY_SHIFT)) {
> + i2c_slave_event(iproc_i2c->slave, I2C_SLAVE_STOP, &value);
> + iproc_i2c->xfer_dir = I2C_SLAVE_DIR_NONE;
> + }
> +
> + /* clear interrupt status */
> + writel(status, iproc_i2c->base + IS_OFFSET);
> +
> + bcm_iproc_i2c_check_slave_status(iproc_i2c);
> + return true;
> +}
> +
> static void bcm_iproc_i2c_read_valid_bytes(struct bcm_iproc_i2c_dev *iproc_i2c)
> {
> struct i2c_msg *msg = iproc_i2c->msg;
> @@ -142,6 +380,18 @@ static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data)
> u32 status = readl(iproc_i2c->base + IS_OFFSET);
> u32 tmp;
>
> +
> + bool ret;
> + u32 sl_status = status & ISR_MASK_SLAVE;
> +
> + if (sl_status) {
> + ret = bcm_iproc_i2c_slave_isr(iproc_i2c, sl_status);
> + if (ret)
> + return IRQ_HANDLED;
> + else
> + return IRQ_NONE;
> + }
> +
> status &= ISR_MASK;
>
> if (!status)
> @@ -224,22 +474,25 @@ static int bcm_iproc_i2c_init(struct bcm_iproc_i2c_dev *iproc_i2c)
>
> /* put controller in reset */
> val = readl(iproc_i2c->base + CFG_OFFSET);
> - val |= 1 << CFG_RESET_SHIFT;
> - val &= ~(1 << CFG_EN_SHIFT);
> + val |= BIT(CFG_RESET_SHIFT);
> + val &= ~(BIT(CFG_RESET_SHIFT));
> writel(val, iproc_i2c->base + CFG_OFFSET);
>
> /* wait 100 usec per spec */
> udelay(100);
>
> /* bring controller out of reset */
> - val &= ~(1 << CFG_RESET_SHIFT);
> + val &= ~(BIT(CFG_RESET_SHIFT));
> writel(val, iproc_i2c->base + CFG_OFFSET);
>
> /* flush TX/RX FIFOs and set RX FIFO threshold to zero */
> - val = (1 << M_FIFO_RX_FLUSH_SHIFT) | (1 << M_FIFO_TX_FLUSH_SHIFT);
> + val = (BIT(M_FIFO_RX_FLUSH_SHIFT) | BIT(M_FIFO_TX_FLUSH_SHIFT));
> writel(val, iproc_i2c->base + M_FIFO_CTRL_OFFSET);
> /* disable all interrupts */
> - writel(0, iproc_i2c->base + IE_OFFSET);
> + val = readl(iproc_i2c->base + IE_OFFSET);
> + val &= ~(IE_M_ALL_INTERRUPT_MASK <<
> + IE_M_ALL_INTERRUPT_SHIFT);
> + writel(val, iproc_i2c->base + IE_OFFSET);
>
> /* clear all pending interrupts */
> writel(0xffffffff, iproc_i2c->base + IS_OFFSET);
> @@ -288,6 +541,14 @@ static int bcm_iproc_i2c_check_status(struct bcm_iproc_i2c_dev *iproc_i2c,
> dev_dbg(iproc_i2c->device, "bus timeout\n");
> return -ETIMEDOUT;
>
> + case M_CMD_STATUS_FIFO_UNDERRUN:
> + dev_dbg(iproc_i2c->device, "FIFO under-run\n");
> + return -ENXIO;
> +
> + case M_CMD_STATUS_RX_FIFO_FULL:
> + dev_dbg(iproc_i2c->device, "Master Rx FIFO full > 10ms\n");
> + return -ETIMEDOUT;
> +
> default:
> dev_dbg(iproc_i2c->device, "unknown error code=%d\n", val);
>
> @@ -442,12 +703,14 @@ static int bcm_iproc_i2c_xfer(struct i2c_adapter *adapter,
>
> static uint32_t bcm_iproc_i2c_functionality(struct i2c_adapter *adap)
> {
> - return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SLAVE;
> }
>
> static const struct i2c_algorithm bcm_iproc_algo = {
> .master_xfer = bcm_iproc_i2c_xfer,
> .functionality = bcm_iproc_i2c_functionality,
> + .reg_slave = bcm_iproc_i2c_reg_slave,
> + .unreg_slave = bcm_iproc_i2c_unreg_slave,
> };
>
> static struct i2c_adapter_quirks bcm_iproc_i2c_quirks = {
> @@ -612,6 +875,46 @@ static int bcm_iproc_i2c_resume(struct device *dev)
> #define BCM_IPROC_I2C_PM_OPS NULL
> #endif /* CONFIG_PM_SLEEP */
>
> +
> +static int bcm_iproc_i2c_reg_slave(struct i2c_client *slave)
> +{
> + struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(slave->adapter);
> +
> + if (iproc_i2c->slave)
> + return -EBUSY;
> +
> + if (slave->flags & I2C_CLIENT_TEN)
> + return -EAFNOSUPPORT;
> +
> + iproc_i2c->slave = slave;
> + bcm_iproc_i2c_slave_init(iproc_i2c, false);
> + return 0;
> +}
> +
> +static int bcm_iproc_i2c_unreg_slave(struct i2c_client *slave)
> +{
> + u32 tmp;
> + struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(slave->adapter);
> +
> + if (!iproc_i2c->slave)
> + return -EINVAL;
> +
> + iproc_i2c->slave = NULL;
> +
> + /* disable all slave interrupts */
> + tmp = readl(iproc_i2c->base + IE_OFFSET);
> + tmp &= ~(IE_S_ALL_INTERRUPT_MASK <<
> + IE_S_ALL_INTERRUPT_SHIFT);
> + writel(tmp, iproc_i2c->base + IE_OFFSET);
> +
> + /* Erase the slave address programmed */
> + tmp = readl(iproc_i2c->base + S_CFG_SMBUS_ADDR_OFFSET);
> + tmp &= ~BIT(S_CFG_EN_NIC_SMB_ADDR3_SHIFT);
> + writel(tmp, iproc_i2c->base + S_CFG_SMBUS_ADDR_OFFSET);
> +
> + return 0;
> +}
> +
> static const struct of_device_id bcm_iproc_i2c_of_match[] = {
> { .compatible = "brcm,iproc-i2c" },
> { /* sentinel */ }
>
Reviewed-by: Ray Jui <ray.jui@xxxxxxxxxxxx>
Thanks!