Messages in this thread | | | Subject | Re: [PATCH RFC 2/2] soc: Add a basic ACPI generic driver | From | John Garry <> | Date | Tue, 28 Jan 2020 15:59:15 +0000 |
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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@huawei.com> >> --- >> 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@huawei.com >> + */ >> + >> +#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
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