On Mon, Jul 3, 2017 at 11:33 PM, Loc Ho <lho@xxxxxxx> wrote:
> The current SPCR code does not check the access width of the mmio, and
> uses a default of 8bit register accesses. This prevents devices that
> only do 16 or 32bit register accesses from working. By simply checking
> this field and setting the mmio string appropriately, this issue can be
> corrected. To prevent any legacy issues, the code will default to 8bit
> accesses if the value is anything but 16 or 32.
>
> Signed-off-by: Loc Ho <lho@xxxxxxx>
> [Re-send as single patch set]
> Signed-off-by: Jon Mason <jon.mason@xxxxxxxxxxxx>
Greg, Aleksey, any objections here?
If not, I'll route this through the ACPI tree.
> ---
> drivers/acpi/spcr.c | 18 ++++++++++++++++--
> include/acpi/acrestyp.h | 7 +++++++
> 2 files changed, 23 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
> index 3afa8c1..2905063 100644
> --- a/drivers/acpi/spcr.c
> +++ b/drivers/acpi/spcr.c
> @@ -74,8 +74,22 @@ int __init parse_spcr(bool earlycon)
> goto done;
> }
>
> - iotype = table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY ?
> - "mmio" : "io";
> + if (table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
> + switch (table->serial_port.access_width) {
> + default:
> + pr_err("Unexpected SPCR Access Width. Defaulting to byte size\n");
> + case ACPI_ACCESS_SIZE_BYTE:
> + iotype = "mmio";
> + break;
> + case ACPI_ACCESS_SIZE_WORD:
> + iotype = "mmio16";
> + break;
> + case ACPI_ACCESS_SIZE_DWORD:
> + iotype = "mmio32";
> + break;
> + }
> + } else
> + iotype = "io";
>
> switch (table->interface_type) {
> case ACPI_DBG2_ARM_SBSA_32BIT:
> diff --git a/include/acpi/acrestyp.h b/include/acpi/acrestyp.h
> index f0f7403..781cb55 100644
> --- a/include/acpi/acrestyp.h
> +++ b/include/acpi/acrestyp.h
> @@ -372,6 +372,13 @@ struct acpi_resource_generic_register {
> u64 address;
> };
>
> +/* Generic Address Space Access Sizes */
> +#define ACPI_ACCESS_SIZE_UNDEFINED 0
> +#define ACPI_ACCESS_SIZE_BYTE 1
> +#define ACPI_ACCESS_SIZE_WORD 2
> +#define ACPI_ACCESS_SIZE_DWORD 3
> +#define ACPI_ACCESS_SIZE_QWORD 4
> +
> struct acpi_resource_gpio {
> u8 revision_id;
> u8 connection_type;
> --
> 1.8.3.1
>
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