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i2c: aspeed: Handle the coalesced stop conditions with the start conditions. 

[ Upstream commit b4cc1cbba5 ]

Some masters may drive the transfers with low enough latency between
the nak/stop phase of the current command and the start/address phase
of the following command that the interrupts are coalesced by the
time we process them.
Handle the stop conditions before processing SLAVE_MATCH to fix the
complaints that sometimes occur below.

"aspeed-i2c-bus 1e78a040.i2c-bus: irq handled != irq. Expected
0x00000086, but was 0x00000084"

Fixes: f9eb91350b ("i2c: aspeed: added slave support for Aspeed I2C driver")
Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
Reviewed-by: Andrew Jeffery <andrew@codeconstruct.com.au>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Quan Nguyen 2023-12-11 17:22:16 +07:00 committed by Greg Kroah-Hartman
parent 5c11f63799
commit 2550d96aa2
1 changed files with 32 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
drivers/i2c/busses/i2c-aspeed.c
View File

@ -249,18 +249,46 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
if (!slave)
return 0;
command = readl(bus->base + ASPEED_I2C_CMD_REG);
/*
* Handle stop conditions early, prior to SLAVE_MATCH. Some masters may drive
* transfers with low enough latency between the nak/stop phase of the current
* command and the start/address phase of the following command that the
* interrupts are coalesced by the time we process them.
*/
if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
bus->slave_state = ASPEED_I2C_SLAVE_STOP;
}
/* Slave was requested, restart state machine. */
if (irq_status & ASPEED_I2CD_INTR_TX_NAK &&
bus->slave_state == ASPEED_I2C_SLAVE_READ_PROCESSED) {
irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
bus->slave_state = ASPEED_I2C_SLAVE_STOP;
}
/* Propagate any stop conditions to the slave implementation. */
if (bus->slave_state == ASPEED_I2C_SLAVE_STOP) {
i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
}
/*
* Now that we've dealt with any potentially coalesced stop conditions,
* address any start conditions.
*/
if (irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH) {
irq_handled |= ASPEED_I2CD_INTR_SLAVE_MATCH;
bus->slave_state = ASPEED_I2C_SLAVE_START;
}
/* Slave is not currently active, irq was for someone else. */
/*
* If the slave has been stopped and not started then slave interrupt
* handling is complete.
*/
if (bus->slave_state == ASPEED_I2C_SLAVE_INACTIVE)
return irq_handled;
command = readl(bus->base + ASPEED_I2C_CMD_REG);
dev_dbg(bus->dev, "slave irq status 0x%08x, cmd 0x%08x\n",
irq_status, command);
@ -279,17 +307,6 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
irq_handled |= ASPEED_I2CD_INTR_RX_DONE;
}
/* Slave was asked to stop. */
if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
bus->slave_state = ASPEED_I2C_SLAVE_STOP;
}
if (irq_status & ASPEED_I2CD_INTR_TX_NAK &&
bus->slave_state == ASPEED_I2C_SLAVE_READ_PROCESSED) {
irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
bus->slave_state = ASPEED_I2C_SLAVE_STOP;
}
switch (bus->slave_state) {
case ASPEED_I2C_SLAVE_READ_REQUESTED:
if (unlikely(irq_status & ASPEED_I2CD_INTR_TX_ACK))
@ -324,8 +341,7 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value);
break;
case ASPEED_I2C_SLAVE_STOP:
i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
/* Stop event handling is done early. Unreachable. */
break;
case ASPEED_I2C_SLAVE_START:
/* Slave was just started. Waiting for the next event. */;