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SubjectRe: [RFC PATCH 3/3] mwifiex: pcie: add reset_wsid quirk for Surface 3
On Sat, May 22, 2021 at 03:18:27PM +0200, Jonas Dreßler wrote:
> From: Tsuchiya Yuto <kitakar@gmail.com>
>
> This commit adds reset_wsid quirk and uses this quirk for Surface 3 on
> card reset.
>
> To reset mwifiex on Surface 3, it seems that calling the _DSM method
> exists in \_SB.WSID [1] device is required.
>
> On Surface 3, calling the _DSM method removes/re-probes the card by
> itself. So, need to place the reset function before performing FLR and
> skip performing any other reset-related works.

Maybe this is a nit-pick, but I understand "probing" to be something
the OS does, namely what we normally call "enumeration," i.e.,
discovering a device.

So it sounds like the _DSM causes a logical hot-removal of the card,
which the PCI hotplug driver should notice and it should remove the
driver and remove the pci_dev.

And the _DSM also causes a hot-add (reading the code below, it looks
like this is actually a second _DSM), which the PCI hotplug driver
should also notice and enumerate the bus (i.e., it reads config space
looking for a device). This all would cause a new pci_dev to be
allocated, resources assigned for its BARs, and the driver .probe()
method to be called again?

That seems like a lot, so maybe I didn't understand what's actually
happening.

> Note that Surface Pro 3 also has the WSID device [2], but it seems to need
> more work. This commit only supports Surface 3 yet.
>
> [1] https://github.com/linux-surface/acpidumps/blob/05cba925f3a515f222acb5b3551a032ddde958fe/surface_3/dsdt.dsl#L11947-L12011
> [2] https://github.com/linux-surface/acpidumps/blob/05cba925f3a515f222acb5b3551a032ddde958fe/surface_pro_3/dsdt.dsl#L12164-L12216
>
> Signed-off-by: Tsuchiya Yuto <kitakar@gmail.com>
> Signed-off-by: Jonas Dreßler <verdre@v0yd.nl>
> ---
> drivers/net/wireless/marvell/mwifiex/pcie.c | 10 ++
> .../wireless/marvell/mwifiex/pcie_quirks.c | 91 +++++++++++++++++++
> .../wireless/marvell/mwifiex/pcie_quirks.h | 6 ++
> 3 files changed, 107 insertions(+)
>
> diff --git a/drivers/net/wireless/marvell/mwifiex/pcie.c b/drivers/net/wireless/marvell/mwifiex/pcie.c
> index d9acfea395ad..6e049236ae1a 100644
> --- a/drivers/net/wireless/marvell/mwifiex/pcie.c
> +++ b/drivers/net/wireless/marvell/mwifiex/pcie.c
> @@ -2969,6 +2969,16 @@ static void mwifiex_pcie_card_reset_work(struct mwifiex_adapter *adapter)
> {
> struct pcie_service_card *card = adapter->card;
>
> + /* On Surface 3, reset_wsid method removes then re-probes card by
> + * itself. So, need to place it here and skip performing any other
> + * reset-related works.
> + */
> + if (card->quirks & QUIRK_FW_RST_WSID_S3) {
> + mwifiex_pcie_reset_wsid_quirk(card->dev);
> + /* skip performing any other reset-related works */
> + return;
> + }
> +
> /* We can't afford to wait here; remove() might be waiting on us. If we
> * can't grab the device lock, maybe we'll get another chance later.
> */
> diff --git a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c
> index b5f214fc1212..f0a6fa0a7ae5 100644
> --- a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c
> +++ b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c
> @@ -9,10 +9,21 @@
> * down, or causes NULL ptr deref).
> */
>
> +#include <linux/acpi.h>
> #include <linux/dmi.h>
>
> #include "pcie_quirks.h"
>
> +/* For reset_wsid quirk */
> +#define ACPI_WSID_PATH "\\_SB.WSID"
> +#define WSID_REV 0x0
> +#define WSID_FUNC_WIFI_PWR_OFF 0x1
> +#define WSID_FUNC_WIFI_PWR_ON 0x2
> +/* WSID _DSM UUID: "534ea3bf-fcc2-4e7a-908f-a13978f0c7ef" */
> +static const guid_t wsid_dsm_guid =
> + GUID_INIT(0x534ea3bf, 0xfcc2, 0x4e7a,
> + 0x90, 0x8f, 0xa1, 0x39, 0x78, 0xf0, 0xc7, 0xef);
> +
> /* quirk table based on DMI matching */
> static const struct dmi_system_id mwifiex_quirk_table[] = {
> {
> @@ -81,6 +92,22 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
> },
> .driver_data = (void *)QUIRK_FW_RST_D3COLD,
> },
> + {
> + .ident = "Surface 3",
> + .matches = {
> + DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
> + DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface 3"),
> + },
> + .driver_data = (void *)QUIRK_FW_RST_WSID_S3,
> + },
> + {
> + .ident = "Surface Pro 3",
> + .matches = {
> + DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
> + DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface Pro 3"),
> + },
> + .driver_data = 0,
> + },
> {}
> };
>
> @@ -97,6 +124,9 @@ void mwifiex_initialize_quirks(struct pcie_service_card *card)
> dev_info(&pdev->dev, "no quirks enabled\n");
> if (card->quirks & QUIRK_FW_RST_D3COLD)
> dev_info(&pdev->dev, "quirk reset_d3cold enabled\n");
> + if (card->quirks & QUIRK_FW_RST_WSID_S3)
> + dev_info(&pdev->dev,
> + "quirk reset_wsid for Surface 3 enabled\n");
> }
>
> static void mwifiex_pcie_set_power_d3cold(struct pci_dev *pdev)
> @@ -153,3 +183,64 @@ int mwifiex_pcie_reset_d3cold_quirk(struct pci_dev *pdev)
>
> return 0;
> }
> +
> +int mwifiex_pcie_reset_wsid_quirk(struct pci_dev *pdev)
> +{
> + acpi_handle handle;
> + union acpi_object *obj;
> + acpi_status status;
> +
> + dev_info(&pdev->dev, "Using reset_wsid quirk to perform FW reset\n");
> +
> + status = acpi_get_handle(NULL, ACPI_WSID_PATH, &handle);
> + if (ACPI_FAILURE(status)) {
> + dev_err(&pdev->dev, "No ACPI handle for path %s\n",
> + ACPI_WSID_PATH);
> + return -ENODEV;
> + }
> +
> + if (!acpi_has_method(handle, "_DSM")) {
> + dev_err(&pdev->dev, "_DSM method not found\n");
> + return -ENODEV;
> + }
> +
> + if (!acpi_check_dsm(handle, &wsid_dsm_guid,
> + WSID_REV, WSID_FUNC_WIFI_PWR_OFF)) {
> + dev_err(&pdev->dev,
> + "_DSM method doesn't support wifi power off func\n");
> + return -ENODEV;
> + }
> +
> + if (!acpi_check_dsm(handle, &wsid_dsm_guid,
> + WSID_REV, WSID_FUNC_WIFI_PWR_ON)) {
> + dev_err(&pdev->dev,
> + "_DSM method doesn't support wifi power on func\n");
> + return -ENODEV;
> + }
> +
> + /* card will be removed immediately after this call on Surface 3 */
> + dev_info(&pdev->dev, "turning wifi off...\n");
> + obj = acpi_evaluate_dsm(handle, &wsid_dsm_guid,
> + WSID_REV, WSID_FUNC_WIFI_PWR_OFF,
> + NULL);
> + if (!obj) {
> + dev_err(&pdev->dev,
> + "device _DSM execution failed for turning wifi off\n");
> + return -EIO;
> + }
> + ACPI_FREE(obj);
> +
> + /* card will be re-probed immediately after this call on Surface 3 */
> + dev_info(&pdev->dev, "turning wifi on...\n");
> + obj = acpi_evaluate_dsm(handle, &wsid_dsm_guid,
> + WSID_REV, WSID_FUNC_WIFI_PWR_ON,
> + NULL);
> + if (!obj) {
> + dev_err(&pdev->dev,
> + "device _DSM execution failed for turning wifi on\n");
> + return -EIO;
> + }
> + ACPI_FREE(obj);
> +
> + return 0;
> +}
> diff --git a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h
> index 549093067813..d90ada3f2daa 100644
> --- a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h
> +++ b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h
> @@ -7,5 +7,11 @@
>
> #define QUIRK_FW_RST_D3COLD BIT(0)
>
> +/* Surface 3 and Surface Pro 3 have the same _DSM method but need to
> + * be handled differently. Currently, only S3 is supported.
> + */
> +#define QUIRK_FW_RST_WSID_S3 BIT(1)
> +
> void mwifiex_initialize_quirks(struct pcie_service_card *card);
> int mwifiex_pcie_reset_d3cold_quirk(struct pci_dev *pdev);
> +int mwifiex_pcie_reset_wsid_quirk(struct pci_dev *pdev);
> --
> 2.31.1
>

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