From 1f0d9cbeec9bb0a1c2013342836f2c9754d6502b Mon Sep 17 00:00:00 2001 From: Jae Hyun Yoo Date: Wed, 9 Oct 2019 14:20:34 -0700 Subject: [PATCH] i2c: aspeed: fix master pending state handling In case of master pending state, it should not trigger a master command, otherwise data could be corrupted because this H/W shares the same data buffer for slave and master operations. It also means that H/W command queue handling is unreliable because of the buffer sharing issue. To fix this issue, it clears command queue if a master command is queued in pending state to use S/W solution instead of H/W command queue handling. Also, it refines restarting mechanism of the pending master command. Fixes: 2e57b7cebb98 ("i2c: aspeed: Add multi-master use case support") Signed-off-by: Jae Hyun Yoo Reviewed-by: Brendan Higgins Acked-by: Joel Stanley Tested-by: Tao Ren Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-aspeed.c | 54 +++++++++++++++++++++------------ 1 file changed, 34 insertions(+), 20 deletions(-) diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c index fa66951b05d0..7b098ff5f5dd 100644 --- a/drivers/i2c/busses/i2c-aspeed.c +++ b/drivers/i2c/busses/i2c-aspeed.c @@ -108,6 +108,12 @@ #define ASPEED_I2CD_S_TX_CMD BIT(2) #define ASPEED_I2CD_M_TX_CMD BIT(1) #define ASPEED_I2CD_M_START_CMD BIT(0) +#define ASPEED_I2CD_MASTER_CMDS_MASK \ + (ASPEED_I2CD_M_STOP_CMD | \ + ASPEED_I2CD_M_S_RX_CMD_LAST | \ + ASPEED_I2CD_M_RX_CMD | \ + ASPEED_I2CD_M_TX_CMD | \ + ASPEED_I2CD_M_START_CMD) /* 0x18 : I2CD Slave Device Address Register */ #define ASPEED_I2CD_DEV_ADDR_MASK GENMASK(6, 0) @@ -336,18 +342,19 @@ static void aspeed_i2c_do_start(struct aspeed_i2c_bus *bus) struct i2c_msg *msg = &bus->msgs[bus->msgs_index]; u8 slave_addr = i2c_8bit_addr_from_msg(msg); - bus->master_state = ASPEED_I2C_MASTER_START; - #if IS_ENABLED(CONFIG_I2C_SLAVE) /* * If it's requested in the middle of a slave session, set the master * state to 'pending' then H/W will continue handling this master * command when the bus comes back to the idle state. */ - if (bus->slave_state != ASPEED_I2C_SLAVE_INACTIVE) + if (bus->slave_state != ASPEED_I2C_SLAVE_INACTIVE) { bus->master_state = ASPEED_I2C_MASTER_PENDING; + return; + } #endif /* CONFIG_I2C_SLAVE */ + bus->master_state = ASPEED_I2C_MASTER_START; bus->buf_index = 0; if (msg->flags & I2C_M_RD) { @@ -422,20 +429,6 @@ static u32 aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus, u32 irq_status) } } -#if IS_ENABLED(CONFIG_I2C_SLAVE) - /* - * A pending master command will be started by H/W when the bus comes - * back to idle state after completing a slave operation so change the - * master state from 'pending' to 'start' at here if slave is inactive. - */ - if (bus->master_state == ASPEED_I2C_MASTER_PENDING) { - if (bus->slave_state != ASPEED_I2C_SLAVE_INACTIVE) - goto out_no_complete; - - bus->master_state = ASPEED_I2C_MASTER_START; - } -#endif /* CONFIG_I2C_SLAVE */ - /* Master is not currently active, irq was for someone else. */ if (bus->master_state == ASPEED_I2C_MASTER_INACTIVE || bus->master_state == ASPEED_I2C_MASTER_PENDING) @@ -462,11 +455,15 @@ static u32 aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus, u32 irq_status) #if IS_ENABLED(CONFIG_I2C_SLAVE) /* * If a peer master starts a xfer immediately after it queues a - * master command, change its state to 'pending' then H/W will - * continue the queued master xfer just after completing the - * slave mode session. + * master command, clear the queued master command and change + * its state to 'pending'. To simplify handling of pending + * cases, it uses S/W solution instead of H/W command queue + * handling. */ if (unlikely(irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH)) { + writel(readl(bus->base + ASPEED_I2C_CMD_REG) & + ~ASPEED_I2CD_MASTER_CMDS_MASK, + bus->base + ASPEED_I2C_CMD_REG); bus->master_state = ASPEED_I2C_MASTER_PENDING; dev_dbg(bus->dev, "master goes pending due to a slave start\n"); @@ -629,6 +626,14 @@ static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id) irq_handled |= aspeed_i2c_master_irq(bus, irq_remaining); } + + /* + * Start a pending master command at here if a slave operation is + * completed. + */ + if (bus->master_state == ASPEED_I2C_MASTER_PENDING && + bus->slave_state == ASPEED_I2C_SLAVE_INACTIVE) + aspeed_i2c_do_start(bus); #else irq_handled = aspeed_i2c_master_irq(bus, irq_remaining); #endif /* CONFIG_I2C_SLAVE */ @@ -691,6 +696,15 @@ static int aspeed_i2c_master_xfer(struct i2c_adapter *adap, ASPEED_I2CD_BUS_BUSY_STS)) aspeed_i2c_recover_bus(bus); + /* + * If timed out and the state is still pending, drop the pending + * master command. + */ + spin_lock_irqsave(&bus->lock, flags); + if (bus->master_state == ASPEED_I2C_MASTER_PENDING) + bus->master_state = ASPEED_I2C_MASTER_INACTIVE; + spin_unlock_irqrestore(&bus->lock, flags); + return -ETIMEDOUT; }