The Aspeed I2C controller maintains a state machine in the command
register, which is mostly used for debug.
Let's start adding a few states to handle abnormal STOP
commands. Today, the model uses the busy status of the bus as a
condition to do so but it is not precise enough.
Also remove the ABNORMAL bit for failing TX commands. This is
incorrect with respect to the specs.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-id: 1494827476-1487-4-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Today, the LAST command is handled with the STOP command but this is
incorrect. Also nack the I2C bus when a LAST is issued.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-id: 1494827476-1487-3-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Multiple I2C commands can be fired simultaneously and the controller
execute the commands following these priorities:
(1) Master Start Command
(2) Master Transmit Command
(3) Slave Transmit Command or Master Receive Command
(4) Master Stop Command
The current code is incorrect with respect to the above sequence and
needs to be reworked to handle each individual command.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-id: 1494827476-1487-2-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The Aspeed AST2400 integrates a set of 14 I2C/SMBus bus controllers
directly connected to the APB bus. They can be programmed as master or
slave but the propopsed model only supports the master mode.
On the TODO list, we also have :
- improve and harden the state machine.
- bus recovery support (used by the Linux driver).
- transfer mode state machine bits. this is not strictly necessary as
it is mostly used for debug. The bus busy bit is deducted from the
I2C core engine of qemu.
- support of the pool buffer: 2048 bytes of internal SRAM (not used
by the Linux driver).
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Message-id: 1464704307-25178-1-git-send-email-clg@kaod.org
[PMM: removed unused functions aspeed_i2c_bus_get_state() and
aspeed_i2c_bus_set_state()]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Cédric Le Goater