On 28/01/2020 15:20, Sudeep Holla wrote:
(commenting on other parts though I am not sure if we want to add this despite it being deprecated) On Tue, Jan 28, 2020 at 07:14:19PM +0800, John Garry wrote:Add a generic driver for platforms which populate their ACPI PPTT processor package ID Type Structure according to suggestion in the ACPI spec - see ACPI 6.2, section 5.2.29.3 ID structure Type 2. The soc_id is from member LEVEL_2_ID. For this, we need to use a whitelist of platforms which are known to populate the structure as suggested. For now, only the vendor and soc_id fields are exposed. Signed-off-by: John Garry<john.garry@xxxxxxxxxx> --- drivers/soc/Makefile | 1 + drivers/soc/acpi_generic.c | 102 +++++++++++++++++++++++++++++++++++++ 2 files changed, 103 insertions(+) create mode 100644 drivers/soc/acpi_generic.c diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile index 8b49d782a1ab..2a59a30a22cd 100644 --- a/drivers/soc/Makefile +++ b/drivers/soc/Makefile @@ -3,6 +3,7 @@ # Makefile for the Linux Kernel SOC specific device drivers. # +obj-$(CONFIG_ACPI_PPTT) += acpi_generic.o obj-$(CONFIG_ARCH_ACTIONS) += actions/ obj-$(CONFIG_SOC_ASPEED) += aspeed/ obj-$(CONFIG_ARCH_AT91) += atmel/ diff --git a/drivers/soc/acpi_generic.c b/drivers/soc/acpi_generic.c new file mode 100644 index 000000000000..34a1f5f8e063 --- /dev/null +++ b/drivers/soc/acpi_generic.c @@ -0,0 +1,102 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) John Garry,john.garry@xxxxxxxxxx + */ + +#define pr_fmt(fmt) "SOC ACPI GENERIC: " fmt + +#include <linux/acpi.h> +#include <linux/sys_soc.h> + +/* + * Known platforms that fill in PPTT package ID structures according to + * ACPI spec examples, that being: + * - Custom driver attribute is in ID Type Structure VENDOR_ID member + * - SoC id is in ID Type Structure LEVEL_2_ID member + * See ACPI SPEC 6.2 Table 5-154 for PPTT ID Type Structure + */ +static struct acpi_platform_list plat_list[] = { + {"HISI ", "HIP08 ", 0, ACPI_SIG_PPTT, all_versions},
Hi Sudeep,
What do you want to match this ? The same silicon can end up with different OEMs and this list just blows up soon for single SoC if used by different OEM/ODMs. I assume we get all the required info from the Type 2 table entry and hence can just rely on that. If PPTT has type 2 entry, just initialise this soc driver and expose the relevant information from the table entry.
As before, the LEVEL_1_ID and LEVEL_2_ID table members are too open to interpretation in the spec to generate a consistent form soc_id and family_id for all platforms.
As such, I was trying to limit to known PPTT implementations and how they should be interpreted. Obviously that's *far* from ideal.
So what's your idea? Just always put LEVEL_1_ID and LEVEL_2_ID in soc driver family_id and soc_id fields, respectively?
Thanks, John
