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Date: Thu, 26 Mar 2015 12:29:41 +0200
From: Mika Westerberg <mika.westerberg@...ux.intel.com>
To: Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>
Cc: rjw@...ysocki.net, robert.moore@...el.com, lv.zheng@...el.com,
lenb@...nel.org, hdegoede@...hat.com, tj@...nel.org,
mjg59@...f.ucam.org, gregkh@...uxfoundation.org,
hanjun.guo@...aro.org, al.stone@...aro.org,
graeme.gregory@...aro.org, leo.duran@....com,
linux-ide@...r.kernel.org, linux-acpi@...r.kernel.org,
linux-kernel@...r.kernel.org, linaro-acpi@...ts.linaro.org
Subject: Re: [V6 PATCH 2/3] ACPI / scan: Add support for ACPI _CLS device
matching
On Wed, Mar 25, 2015 at 03:46:07PM -0500, Suravee Suthikulpanit wrote:
> Device drivers typically use ACPI _HIDs/_CIDs listed in struct device_driver
> acpi_match_table to match devices. However, for generic drivers, we do not
> want to list _HID for all supported devices. Also, certain classes of devices
> do not have _CID (e.g. SATA, USB). Instead, we can leverage ACPI _CLS,
> which specifies PCI-defined class code (i.e. base-class, subclass and
> programming interface). This patch adds support for matching ACPI devices using
> the _CLS method.
>
> To support loadable module, current design uses _HID or _CID to match device's
> modalias. With the new way of matching with _CLS this would requires modification
> to the current ACPI modalias key to include _CLS. This patch appends PCI-defined
> class-code to the existing ACPI modalias as following.
>
> acpi:<HID>:<CID1>:<CID2>:..:<CIDn>:<bbsspp>:
> E.g:
> # cat /sys/devices/platform/AMDI0600:00/modalias
> acpi:AMDI0600:010601:
>
> where bb is th base-class code, ss is te sub-class code, and pp is the
> programming interface code
>
> Since there would not be _HID/_CID in the ACPI matching table of the driver,
> this patch adds a field to acpi_device_id to specify the matching _CLS.
>
> static const struct acpi_device_id ahci_acpi_match[] = {
> { ACPI_DEVICE_CLASS(PCI_CLASS_STORAGE_SATA_AHCI, 0xFFFFFF) },
> {},
> };
>
> In this case, the corresponded entry in modules.alias file would be:
>
> alias acpi*:010601:* ahci_platform
>
> Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>
> ---
> drivers/acpi/scan.c | 39 +++++++++++++++++++++++++++++++++++----
> include/acpi/acnames.h | 1 +
> include/acpi/actypes.h | 4 +++-
> include/linux/mod_devicetable.h | 4 ++++
> scripts/mod/devicetable-offsets.c | 2 ++
> scripts/mod/file2alias.c | 32 ++++++++++++++++++++++++++++++--
> 6 files changed, 75 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index 52a62aa..f26bf80 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -895,6 +895,32 @@ static void acpi_device_remove_files(struct acpi_device *dev)
> ACPI Bus operations
> -------------------------------------------------------------------------- */
>
> +static bool __acpi_match_device_cls(const struct acpi_device_id *id,
> + struct acpi_hardware_id *hwid)
> +{
> + int i, msk, byte_shift;
> + bool found = true;
> + char buf[3];
> +
> + if (!id->cls)
> + return false;
> +
> + /* Apply class-code bitmask, before checking each class-code byte */
> + for (i = 1; i <= 3; i++) {
> + byte_shift = 8 * (3 - i);
> + msk = (id->cls_msk >> byte_shift) & 0xFF;
> + if (!msk)
> + continue;
> +
> + sprintf(buf, "%02x", (id->cls >> byte_shift) & msk);
> + if (strncmp(buf, &hwid->id[(i - 1) * 2], 2)) {
> + found = false;
> + break;
You can return false directly here.
> + }
> + }
> + return found;
> +}
> +
> static const struct acpi_device_id *__acpi_match_device(
> struct acpi_device *device, const struct acpi_device_id *ids)
> {
> @@ -908,11 +934,14 @@ static const struct acpi_device_id *__acpi_match_device(
> if (!device->status.present)
> return NULL;
>
> - for (id = ids; id->id[0]; id++)
> - list_for_each_entry(hwid, &device->pnp.ids, list)
> - if (!strcmp((char *) id->id, hwid->id))
> + for (id = ids; id->id[0] || id->cls; id++) {
> + list_for_each_entry(hwid, &device->pnp.ids, list) {
> + if (id->id[0] && !strcmp((char *) id->id, hwid->id))
> return id;
> -
> + else if (__acpi_match_device_cls(id, hwid))
> + return id;
> + }
> + }
> return NULL;
> }
>
> @@ -2005,6 +2034,8 @@ static void acpi_set_pnp_ids(acpi_handle handle, struct acpi_device_pnp *pnp,
> if (info->valid & ACPI_VALID_UID)
> pnp->unique_id = kstrdup(info->unique_id.string,
> GFP_KERNEL);
> + if (info->valid & ACPI_VALID_CLS)
> + acpi_add_id(pnp, info->cls.string);
>
> kfree(info);
>
> diff --git a/include/acpi/acnames.h b/include/acpi/acnames.h
> index 273de70..b52c0dc 100644
> --- a/include/acpi/acnames.h
> +++ b/include/acpi/acnames.h
> @@ -51,6 +51,7 @@
> #define METHOD_NAME__BBN "_BBN"
> #define METHOD_NAME__CBA "_CBA"
> #define METHOD_NAME__CID "_CID"
> +#define METHOD_NAME__CLS "_CLS"
> #define METHOD_NAME__CRS "_CRS"
> #define METHOD_NAME__DDN "_DDN"
> #define METHOD_NAME__HID "_HID"
> diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h
> index b034f10..ab3dac8 100644
> --- a/include/acpi/actypes.h
> +++ b/include/acpi/actypes.h
> @@ -1148,7 +1148,7 @@ struct acpi_device_info {
> u32 name; /* ACPI object Name */
> acpi_object_type type; /* ACPI object Type */
> u8 param_count; /* If a method, required parameter count */
> - u8 valid; /* Indicates which optional fields are valid */
> + u16 valid; /* Indicates which optional fields are valid */
> u8 flags; /* Miscellaneous info */
> u8 highest_dstates[4]; /* _sx_d values: 0xFF indicates not valid */
> u8 lowest_dstates[5]; /* _sx_w values: 0xFF indicates not valid */
> @@ -1157,6 +1157,7 @@ struct acpi_device_info {
> struct acpi_pnp_device_id hardware_id; /* _HID value */
> struct acpi_pnp_device_id unique_id; /* _UID value */
> struct acpi_pnp_device_id subsystem_id; /* _SUB value */
> + struct acpi_pnp_device_id cls; /* _CLS value */
> struct acpi_pnp_device_id_list compatible_id_list; /* _CID list <must be last> */
> };
>
> @@ -1174,6 +1175,7 @@ struct acpi_device_info {
> #define ACPI_VALID_CID 0x20
> #define ACPI_VALID_SXDS 0x40
> #define ACPI_VALID_SXWS 0x80
> +#define ACPI_VALID_CLS 0x100
>
> /* Flags for _STA return value (current_status above) */
>
> diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
> index e530533..9563abe 100644
> --- a/include/linux/mod_devicetable.h
> +++ b/include/linux/mod_devicetable.h
> @@ -189,8 +189,12 @@ struct css_device_id {
> struct acpi_device_id {
> __u8 id[ACPI_ID_LEN];
> kernel_ulong_t driver_data;
> + __u32 cls;
> + __u32 cls_msk;
> };
>
> +#define ACPI_DEVICE_CLASS(cls, msk) "", 0, cls, msk
Consider moving this to <linux/acpi.h>, just like PCI_DEVICE_CLASS() is
defined in <linux/pci.h>.
Also please use designated initializers here, eg:
#define ACPI_DEVICE_CLASS(cls, msk) .cls = (cls), .cls_mask = (msk)
Once done you can add my,
Acked-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
> +
> #define PNP_ID_LEN 8
> #define PNP_MAX_DEVICES 8
--
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