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.

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 <kita...@gmail.com>
---
Current issues:
1) After reset with this quirk, ASPM settings don't get restored.

Below is the "sudo lspci -nnvvv" diff before/after fw reset on Surface 3:

    #
    # root port of wifi:
    # 00:1c.0 PCI bridge [0604]: Intel Corporation Atom/Celeron/Pentium 
Processor x5-E8000/J3xxx/N3xxx Series PCI Express Port #1 [8086:22c8] (rev 20) 
(prog-if 00 [Normal decode])
    #
    @@ -103,7 +103,7 @@
                    DevSta: CorrErr+ NonFatalErr- FatalErr- UnsupReq- AuxPwr+ 
TransPend-
                    LnkCap: Port #1, Speed 5GT/s, Width x1, ASPM L0s L1, Exit 
Latency L0s <512ns, L1 <16us
                            ClockPM- Surprise- LLActRep+ BwNot+ ASPMOptComp-
    -               LnkCtl: ASPM L0s L1 Enabled; RCB 64 bytes, Disabled- 
CommClk+
    +               LnkCtl: ASPM Disabled; RCB 64 bytes, Disabled- CommClk+
                            ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
                    LnkSta: Speed 2.5GT/s (downgraded), Width x1 (ok)
                            TrErr- Train- SlotClk+ DLActive+ BWMgmt+ ABWMgmt-
    
    #
    # no changes on wifi regarding ASPM
    #

As you see, the ASPM of wifi root port is disabled after fw reset (thus
breaks S0ix).

2) Creating a new device driver for the WSID device is better?

then export the reset function, and call it from mwifiex. As the comments
in code states, on S3, calling the _DSM methods immediately
remove/re-probe mwifiex. So, resetting the wifi externally is a better
idea? (Also in this way, hopefully supporting SP3 may become easier.)

 drivers/net/wireless/marvell/mwifiex/pcie.c   | 10 +++
 .../wireless/marvell/mwifiex/pcie_quirks.c    | 77 ++++++++++++++++++-
 .../wireless/marvell/mwifiex/pcie_quirks.h    |  5 ++
 3 files changed, 91 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/pcie.c 
b/drivers/net/wireless/marvell/mwifiex/pcie.c
index c0c4b5a9149ab..b3aacd19cc48f 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie.c
+++ b/drivers/net/wireless/marvell/mwifiex/pcie.c
@@ -2966,6 +2966,16 @@ 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 edc739c542fea..f0a6fa0a7ae5f 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[] = {
        {
@@ -87,7 +98,7 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
                        DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Microsoft 
Corporation"),
                        DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface 3"),
                },
-               .driver_data = 0,
+               .driver_data = (void *)QUIRK_FW_RST_WSID_S3,
        },
        {
                .ident = "Surface Pro 3",
@@ -113,6 +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)
@@ -169,3 +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 8b9dcb5070d87..3ef7440418e32 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h
+++ b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h
@@ -7,6 +7,11 @@
 
 /* quirks */
 #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);
-- 
2.29.1

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