From e28000a38da803de8d90727bec45f3d7c831a59a Mon Sep 17 00:00:00 2001 From: Shinya Kuribayashi Date: Fri, 6 Nov 2009 21:44:37 +0900 Subject: i2c-designware: Don't use the IC_CLR_INTR register to clear interrupts We're strongly discouraged from using the IC_CLR_INTR register because it clears all software-clearable interrupts asserted at the moment. stat = readl(IC_INTR_STAT); : : <=== Interrupts asserted during this period will be lost : readl(IC_CLR_INTR); Instead, use the separately-prepared IC_CLR_* registers. At the same time, this patch adds all remaining interrupt definitions available in the DesignWare I2C hardware. Signed-off-by: Shinya Kuribayashi Signed-off-by: Ben Dooks --- drivers/i2c/busses/i2c-designware.c | 84 ++++++++++++++++++++++++++++++++++--- 1 file changed, 79 insertions(+), 5 deletions(-) (limited to 'drivers/i2c') diff --git a/drivers/i2c/busses/i2c-designware.c b/drivers/i2c/busses/i2c-designware.c index a4f928e1fc5..eeb1915c59e 100644 --- a/drivers/i2c/busses/i2c-designware.c +++ b/drivers/i2c/busses/i2c-designware.c @@ -49,7 +49,18 @@ #define DW_IC_FS_SCL_LCNT 0x20 #define DW_IC_INTR_STAT 0x2c #define DW_IC_INTR_MASK 0x30 +#define DW_IC_RAW_INTR_STAT 0x34 #define DW_IC_CLR_INTR 0x40 +#define DW_IC_CLR_RX_UNDER 0x44 +#define DW_IC_CLR_RX_OVER 0x48 +#define DW_IC_CLR_TX_OVER 0x4c +#define DW_IC_CLR_RD_REQ 0x50 +#define DW_IC_CLR_TX_ABRT 0x54 +#define DW_IC_CLR_RX_DONE 0x58 +#define DW_IC_CLR_ACTIVITY 0x5c +#define DW_IC_CLR_STOP_DET 0x60 +#define DW_IC_CLR_START_DET 0x64 +#define DW_IC_CLR_GEN_CALL 0x68 #define DW_IC_ENABLE 0x6c #define DW_IC_STATUS 0x70 #define DW_IC_TXFLR 0x74 @@ -64,9 +75,18 @@ #define DW_IC_CON_RESTART_EN 0x20 #define DW_IC_CON_SLAVE_DISABLE 0x40 -#define DW_IC_INTR_TX_EMPTY 0x10 -#define DW_IC_INTR_TX_ABRT 0x40 +#define DW_IC_INTR_RX_UNDER 0x001 +#define DW_IC_INTR_RX_OVER 0x002 +#define DW_IC_INTR_RX_FULL 0x004 +#define DW_IC_INTR_TX_OVER 0x008 +#define DW_IC_INTR_TX_EMPTY 0x010 +#define DW_IC_INTR_RD_REQ 0x020 +#define DW_IC_INTR_TX_ABRT 0x040 +#define DW_IC_INTR_RX_DONE 0x080 +#define DW_IC_INTR_ACTIVITY 0x100 #define DW_IC_INTR_STOP_DET 0x200 +#define DW_IC_INTR_START_DET 0x400 +#define DW_IC_INTR_GEN_CALL 0x800 #define DW_IC_STATUS_ACTIVITY 0x1 @@ -439,6 +459,61 @@ static void dw_i2c_pump_msg(unsigned long data) writel(intr_mask, dev->base + DW_IC_INTR_MASK); } +static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev) +{ + u32 stat; + + /* + * The IC_INTR_STAT register just indicates "enabled" interrupts. + * Ths unmasked raw version of interrupt status bits are available + * in the IC_RAW_INTR_STAT register. + * + * That is, + * stat = readl(IC_INTR_STAT); + * equals to, + * stat = readl(IC_RAW_INTR_STAT) & readl(IC_INTR_MASK); + * + * The raw version might be useful for debugging purposes. + */ + stat = readl(dev->base + DW_IC_INTR_STAT); + + /* + * Do not use the IC_CLR_INTR register to clear interrupts, or + * you'll miss some interrupts, triggered during the period from + * readl(IC_INTR_STAT) to readl(IC_CLR_INTR). + * + * Instead, use the separately-prepared IC_CLR_* registers. + */ + if (stat & DW_IC_INTR_RX_UNDER) + readl(dev->base + DW_IC_CLR_RX_UNDER); + if (stat & DW_IC_INTR_RX_OVER) + readl(dev->base + DW_IC_CLR_RX_OVER); + if (stat & DW_IC_INTR_TX_OVER) + readl(dev->base + DW_IC_CLR_TX_OVER); + if (stat & DW_IC_INTR_RD_REQ) + readl(dev->base + DW_IC_CLR_RD_REQ); + if (stat & DW_IC_INTR_TX_ABRT) { + /* + * The IC_TX_ABRT_SOURCE register is cleared whenever + * the IC_CLR_TX_ABRT is read. Preserve it beforehand. + */ + dev->abort_source = readl(dev->base + DW_IC_TX_ABRT_SOURCE); + readl(dev->base + DW_IC_CLR_TX_ABRT); + } + if (stat & DW_IC_INTR_RX_DONE) + readl(dev->base + DW_IC_CLR_RX_DONE); + if (stat & DW_IC_INTR_ACTIVITY) + readl(dev->base + DW_IC_CLR_ACTIVITY); + if (stat & DW_IC_INTR_STOP_DET) + readl(dev->base + DW_IC_CLR_STOP_DET); + if (stat & DW_IC_INTR_START_DET) + readl(dev->base + DW_IC_CLR_START_DET); + if (stat & DW_IC_INTR_GEN_CALL) + readl(dev->base + DW_IC_CLR_GEN_CALL); + + return stat; +} + /* * Interrupt service routine. This gets called whenever an I2C interrupt * occurs. @@ -448,16 +523,15 @@ static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id) struct dw_i2c_dev *dev = dev_id; u32 stat; - stat = readl(dev->base + DW_IC_INTR_STAT); + stat = i2c_dw_read_clear_intrbits(dev); dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat); + if (stat & DW_IC_INTR_TX_ABRT) { - dev->abort_source = readl(dev->base + DW_IC_TX_ABRT_SOURCE); dev->cmd_err |= DW_IC_ERR_TX_ABRT; dev->status = STATUS_IDLE; } else if (stat & DW_IC_INTR_TX_EMPTY) tasklet_schedule(&dev->pump_msg); - readl(dev->base + DW_IC_CLR_INTR); /* clear interrupts */ writel(0, dev->base + DW_IC_INTR_MASK); /* disable interrupts */ if (stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) complete(&dev->cmd_complete); -- cgit v1.2.3-70-g09d2