From 78d5e9e299e31bc2deaaa94a45bf8ea024f27e8c Mon Sep 17 00:00:00 2001 From: Jan Dabros Date: Tue, 8 Feb 2022 15:12:18 +0100 Subject: i2c: designware: Add AMD PSP I2C bus support Implement an I2C controller sharing mechanism between the host (kernel) and PSP co-processor on some platforms equipped with AMD Cezanne SoC. On these platforms we need to implement "software" i2c arbitration. Default arbitration owner is PSP and kernel asks for acquire as well as inform about release of the i2c bus via mailbox mechanism. +---------+ <- ACQUIRE | | +---------| CPU |\ | | | \ +----------+ SDA | +---------+ \ | |------- MAILBOX +--> | I2C-DW | SCL | +---------+ | |------- | | | +----------+ +---------| PSP | <- ACK | | +---------+ +---------+ <- RELEASE | | +---------| CPU | | | | +----------+ SDA | +---------+ | |------- MAILBOX +--> | I2C-DW | SCL | +---------+ / | |------- | | | / +----------+ +---------| PSP |/ <- ACK | | +---------+ The solution is similar to i2c-designware-baytrail.c implementation, where we are using a generic i2c-designware-* driver with a small "wrapper". In contrary to baytrail semaphore implementation, beside internal acquire_lock() and release_lock() methods we are also applying quirks to lock_bus() and unlock_bus() global adapter methods. With this in place all i2c clients drivers may lock i2c bus for a desired number of i2c transactions (e.g. write-wait-read) without being aware of that such bus is shared with another entity. Modify i2c_dw_probe_lock_support() to select correct semaphore implementation at runtime, since now we have more than one available. Configure new matching ACPI ID "AMDI0019" and register ARBITRATION_SEMAPHORE flag in order to distinguish setup with PSP arbitration. Add myself as a reviewer for I2C DesignWare in order to help with reviewing and testing possible changes touching new i2c-designware-amdpsp.c module. Signed-off-by: Jan Dabros Reviewed-by: Andy Shevchenko Acked-by: Jarkko Nikula Tested-by: Jarkko Nikula [wsa: removed unneeded blank line and curly braces] Signed-off-by: Wolfram Sang --- drivers/acpi/acpi_apd.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'drivers/acpi') diff --git a/drivers/acpi/acpi_apd.c b/drivers/acpi/acpi_apd.c index e7934ba79b02..ad245bbd965e 100644 --- a/drivers/acpi/acpi_apd.c +++ b/drivers/acpi/acpi_apd.c @@ -232,12 +232,13 @@ static const struct acpi_device_id acpi_apd_device_ids[] = { /* Generic apd devices */ #ifdef CONFIG_X86_AMD_PLATFORM_DEVICE { "AMD0010", APD_ADDR(cz_i2c_desc) }, - { "AMDI0010", APD_ADDR(wt_i2c_desc) }, { "AMD0020", APD_ADDR(cz_uart_desc) }, - { "AMDI0020", APD_ADDR(cz_uart_desc) }, - { "AMDI0022", APD_ADDR(cz_uart_desc) }, { "AMD0030", }, { "AMD0040", APD_ADDR(fch_misc_desc)}, + { "AMDI0010", APD_ADDR(wt_i2c_desc) }, + { "AMDI0019", APD_ADDR(wt_i2c_desc) }, + { "AMDI0020", APD_ADDR(cz_uart_desc) }, + { "AMDI0022", APD_ADDR(cz_uart_desc) }, { "HYGO0010", APD_ADDR(wt_i2c_desc) }, #endif #ifdef CONFIG_ARM64 -- cgit v1.2.3-70-g09d2