From 3e359be7e8a96b068479d01aa671ff642d291bca Mon Sep 17 00:00:00 2001 From: Jae Hyun Yoo Date: Thu, 11 Jul 2019 13:53:34 -0700 Subject: [PATCH] i2c: aspeed: add H/W timeout support This commit adds I2C H/W timeout support. Signed-off-by: Jae Hyun Yoo --- drivers/i2c/busses/i2c-aspeed.c | 82 ++++++++++++++++++++++++++++++++++++++--- 1 file changed, 76 insertions(+), 6 deletions(-) diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c index 891b2b5c4b7a..71ebf3bbf38b 100644 --- a/drivers/i2c/busses/i2c-aspeed.c +++ b/drivers/i2c/busses/i2c-aspeed.c @@ -55,6 +55,7 @@ /* Device Register Definition */ /* 0x00 : I2CD Function Control Register */ #define ASPEED_I2CD_BUFFER_PAGE_SEL_MASK GENMASK(22, 20) +#define ASPEED_I2CD_BUS_AUTO_RECOVERY_EN BIT(17) #define ASPEED_I2CD_MULTI_MASTER_DIS BIT(15) #define ASPEED_I2CD_SDA_DRIVE_1T_EN BIT(8) #define ASPEED_I2CD_M_SDA_DRIVE_1T_EN BIT(7) @@ -71,10 +72,14 @@ #define ASPEED_I2CD_TIME_SCL_HIGH_MASK GENMASK(19, 16) #define ASPEED_I2CD_TIME_SCL_LOW_SHIFT 12 #define ASPEED_I2CD_TIME_SCL_LOW_MASK GENMASK(15, 12) +#define ASPEED_I2CD_TIME_TIMEOUT_BASE_DIVISOR_SHIFT 8 +#define ASPEED_I2CD_TIME_TIMEOUT_BASE_DIVISOR_MASK GENMASK(9, 8) #define ASPEED_I2CD_TIME_BASE_DIVISOR_MASK GENMASK(3, 0) #define ASPEED_I2CD_TIME_SCL_REG_MAX GENMASK(3, 0) + /* 0x08 : I2CD Clock and AC Timing Control Register #2 */ -#define ASPEED_NO_TIMEOUT_CTRL 0 +#define ASPEED_I2CD_TIMEOUT_CYCLES_SHIFT 0 +#define ASPEED_I2CD_TIMEOUT_CYCLES_MASK GENMASK(4, 0) /* 0x0c : I2CD Interrupt Control Register & * 0x10 : I2CD Interrupt Status Register @@ -82,6 +87,7 @@ * These share bit definitions, so use the same values for the enable & * status bits. */ +#define ASPEED_I2CD_INTR_SLAVE_INACTIVE_TIMEOUT BIT(15) #define ASPEED_I2CD_INTR_SDA_DL_TIMEOUT BIT(14) #define ASPEED_I2CD_INTR_BUS_RECOVER_DONE BIT(13) #define ASPEED_I2CD_INTR_GCALL_ADDR BIT(8) @@ -98,8 +104,11 @@ ASPEED_I2CD_INTR_SCL_TIMEOUT | \ ASPEED_I2CD_INTR_ABNORMAL | \ ASPEED_I2CD_INTR_ARBIT_LOSS) +#define ASPEED_I2CD_INTR_SLAVE_ERRORS \ + ASPEED_I2CD_INTR_SLAVE_INACTIVE_TIMEOUT #define ASPEED_I2CD_INTR_ALL \ - (ASPEED_I2CD_INTR_SDA_DL_TIMEOUT | \ + (ASPEED_I2CD_INTR_SLAVE_INACTIVE_TIMEOUT | \ + ASPEED_I2CD_INTR_SDA_DL_TIMEOUT | \ ASPEED_I2CD_INTR_BUS_RECOVER_DONE | \ ASPEED_I2CD_INTR_SCL_TIMEOUT | \ ASPEED_I2CD_INTR_ABNORMAL | \ @@ -186,6 +195,7 @@ struct aspeed_i2c_bus { u32 divisor); unsigned long parent_clk_frequency; u32 bus_frequency; + u32 hw_timeout_ms; /* Transaction state. */ enum aspeed_i2c_master_state master_state; struct i2c_msg *msgs; @@ -303,6 +313,14 @@ static int aspeed_i2c_recover_bus(struct aspeed_i2c_bus *bus) } #if IS_ENABLED(CONFIG_I2C_SLAVE) +static int aspeed_i2c_check_slave_error(u32 irq_status) +{ + if (irq_status & ASPEED_I2CD_INTR_SLAVE_INACTIVE_TIMEOUT) + return -EIO; + + return 0; +} + static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status) { u32 command, irq_handled = 0; @@ -313,6 +331,14 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status) if (!slave) return 0; + if (aspeed_i2c_check_slave_error(irq_status)) { + dev_dbg(bus->dev, "received slave error interrupt: 0x%08x\n", + irq_status); + irq_handled |= (irq_status & ASPEED_I2CD_INTR_SLAVE_ERRORS); + bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE; + return irq_handled; + } + command = readl(bus->base + ASPEED_I2C_CMD_REG); /* Slave was requested, restart state machine. */ @@ -655,7 +681,7 @@ static void aspeed_i2c_next_msg_or_stop(struct aspeed_i2c_bus *bus) } } -static int aspeed_i2c_is_irq_error(u32 irq_status) +static int aspeed_i2c_check_master_error(u32 irq_status) { if (irq_status & ASPEED_I2CD_INTR_ARBIT_LOSS) return -EAGAIN; @@ -686,9 +712,9 @@ static u32 aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus, u32 irq_status) * should clear the command queue effectively taking us back to the * INACTIVE state. */ - ret = aspeed_i2c_is_irq_error(irq_status); + ret = aspeed_i2c_check_master_error(irq_status); if (ret) { - dev_dbg(bus->dev, "received error interrupt: 0x%08x\n", + dev_dbg(bus->dev, "received master error interrupt: 0x%08x\n", irq_status); irq_handled |= (irq_status & ASPEED_I2CD_INTR_MASTER_ERRORS); if (bus->master_state != ASPEED_I2C_MASTER_INACTIVE) { @@ -1264,6 +1290,7 @@ static u32 aspeed_i2c_25xx_get_clk_reg_val(struct device *dev, u32 divisor) /* precondition: bus.lock has been acquired. */ static int aspeed_i2c_init_clk(struct aspeed_i2c_bus *bus) { + u32 timeout_base_divisor, timeout_tick_us, timeout_cycles; u32 divisor, clk_reg_val; divisor = DIV_ROUND_UP(bus->parent_clk_frequency, bus->bus_frequency); @@ -1272,8 +1299,46 @@ static int aspeed_i2c_init_clk(struct aspeed_i2c_bus *bus) ASPEED_I2CD_TIME_THDSTA_MASK | ASPEED_I2CD_TIME_TACST_MASK); clk_reg_val |= bus->get_clk_reg_val(bus->dev, divisor); + + if (bus->hw_timeout_ms) { + u8 div_max = ASPEED_I2CD_TIME_TIMEOUT_BASE_DIVISOR_MASK >> + ASPEED_I2CD_TIME_TIMEOUT_BASE_DIVISOR_SHIFT; + u8 cycles_max = ASPEED_I2CD_TIMEOUT_CYCLES_MASK >> + ASPEED_I2CD_TIMEOUT_CYCLES_SHIFT; + + timeout_base_divisor = 0; + + do { + timeout_tick_us = 1000 * (16384 << + (timeout_base_divisor << 1)) / + (bus->parent_clk_frequency / 1000); + + if (timeout_base_divisor == div_max || + timeout_tick_us * ASPEED_I2CD_TIMEOUT_CYCLES_MASK >= + bus->hw_timeout_ms * 1000) + break; + } while (timeout_base_divisor++ < div_max); + + if (timeout_tick_us) { + timeout_cycles = DIV_ROUND_UP(bus->hw_timeout_ms * 1000, + timeout_tick_us); + if (timeout_cycles == 0) + timeout_cycles = 1; + else if (timeout_cycles > cycles_max) + timeout_cycles = cycles_max; + } else { + timeout_cycles = 0; + } + } else { + timeout_base_divisor = 0; + timeout_cycles = 0; + } + + clk_reg_val |= FIELD_PREP(ASPEED_I2CD_TIME_TIMEOUT_BASE_DIVISOR_MASK, + timeout_base_divisor); + writel(clk_reg_val, bus->base + ASPEED_I2C_AC_TIMING_REG1); - writel(ASPEED_NO_TIMEOUT_CTRL, bus->base + ASPEED_I2C_AC_TIMING_REG2); + writel(timeout_cycles, bus->base + ASPEED_I2C_AC_TIMING_REG2); return 0; } @@ -1288,6 +1353,11 @@ static int aspeed_i2c_init(struct aspeed_i2c_bus *bus, /* Disable everything. */ writel(0, bus->base + ASPEED_I2C_FUN_CTRL_REG); + device_property_read_u32(&pdev->dev, "aspeed,hw-timeout-ms", + &bus->hw_timeout_ms); + if (bus->hw_timeout_ms) + fun_ctrl_reg |= ASPEED_I2CD_BUS_AUTO_RECOVERY_EN; + ret = aspeed_i2c_init_clk(bus); if (ret < 0) return ret; -- 2.7.4