Re: [RFC PATCH 2/7] aspeed: i2c: Add ctrl_global_rsvd property

[Cédric Le Goater]

Hello Joe,

On 3/31/22 06:32, Joe Komlodi wrote:
> The Aspeed I2C controller is used across other SKUs that have different
> reserved bits for the ctrl_global_rsvd register.

So some AST2600 SoCs can not set the new/old modes and the clock divider ?
 

> Signed-off-by: Joe Komlodi <komlodi@google.com>
> Change-Id: I606c5933c527274a9d2b0afe559b2e895767636c
> ---
>   hw/arm/aspeed_ast2600.c     | 2 ++
>   hw/i2c/aspeed_i2c.c         | 4 ++++
>   include/hw/i2c/aspeed_i2c.h | 2 ++
>   3 files changed, 8 insertions(+)
>
> diff --git a/hw/arm/aspeed_ast2600.c b/hw/arm/aspeed_ast2600.c
> index 43f8223139..9f14a35a75 100644
> --- a/hw/arm/aspeed_ast2600.c
> +++ b/hw/arm/aspeed_ast2600.c
> @@ -344,6 +344,8 @@ static void aspeed_soc_ast2600_realize(DeviceState *dev, 
> Error **errp)
>                      serial_hd(0), DEVICE_LITTLE_ENDIAN);
>   
>       /* I2C */
> +    object_property_set_int(OBJECT(&s->i2c), "ctrl-global-rsvd", 0xfffc3e00,
> +                            &error_abort);

Ideally, this should be set from a specific machine and not from the SoC
as it impacts all machines. One way to do this is to use an alias. See the
hw-strap1/2 properties.

Thanks,

C.

>       object_property_set_link(OBJECT(&s->i2c), "dram", OBJECT(s->dram_mr),
>                                &error_abort);
>       if (!sysbus_realize(SYS_BUS_DEVICE(&s->i2c), errp)) {
> diff --git a/hw/i2c/aspeed_i2c.c b/hw/i2c/aspeed_i2c.c
> index 03a4f5a910..97eb9d5792 100644
> --- a/hw/i2c/aspeed_i2c.c
> +++ b/hw/i2c/aspeed_i2c.c
> @@ -648,6 +648,7 @@ static void aspeed_i2c_ctrl_write(void *opaque, hwaddr 
> offset,
>   
>       switch (offset) {
>       case I2C_CTRL_GLOBAL:
> +        value &= ~s->ctrl_global_rsvd;
>           s->ctrl_global = value;
>           break;
>       case I2C_CTRL_STATUS:
> @@ -730,6 +731,7 @@ static const VMStateDescription aspeed_i2c_vmstate = {
>       .minimum_version_id = 2,
>       .fields = (VMStateField[]) {
>           VMSTATE_UINT32(intr_status, AspeedI2CState),
> +        VMSTATE_UINT32(ctrl_global_rsvd, AspeedI2CState),
>           VMSTATE_STRUCT_ARRAY(busses, AspeedI2CState,
>                                ASPEED_I2C_NR_BUSSES, 1, aspeed_i2c_bus_vmstate,
>                                AspeedI2CBus),
> @@ -828,6 +830,8 @@ static void aspeed_i2c_realize(DeviceState *dev, Error 
> **errp)
>   static Property aspeed_i2c_properties[] = {
>       DEFINE_PROP_LINK("dram", AspeedI2CState, dram_mr,
>                        TYPE_MEMORY_REGION, MemoryRegion *),
> +    DEFINE_PROP_UINT32("ctrl-global-rsvd", AspeedI2CState, ctrl_global_rsvd,
> +                       0xfffffffe),
>       DEFINE_PROP_END_OF_LIST(),
>   };
>   
> diff --git a/include/hw/i2c/aspeed_i2c.h b/include/hw/i2c/aspeed_i2c.h
> index 4b9be09274..3912fcc3ff 100644
> --- a/include/hw/i2c/aspeed_i2c.h
> +++ b/include/hw/i2c/aspeed_i2c.h
> @@ -71,6 +71,8 @@ struct AspeedI2CState {
>       MemoryRegion pool_iomem;
>       uint8_t pool[ASPEED_I2C_MAX_POOL_SIZE];
>   
> +    uint32_t ctrl_global_rsvd;



> +
>       AspeedI2CBus busses[ASPEED_I2C_NR_BUSSES];
>       MemoryRegion *dram_mr;
>       AddressSpace dram_as;