drm/nouveau/secboot: workaround bug when starting SEC2 firmware

For some unknown reason the LS SEC2 firmware needs to be started twice
to operate. Detect and address that condition.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/secboot/acr_r352.c b/drivers/gpu/drm/nouveau/nvkm/subdev/secboot/acr_r352.c
index b4e0add..72ca537 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/secboot/acr_r352.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/secboot/acr_r352.c
@@ -26,6 +26,7 @@
 #include <core/firmware.h>
 #include <engine/falcon.h>
 #include <subdev/mc.h>
+#include <subdev/timer.h>
 #include <subdev/pmu.h>
 #include <core/msgqueue.h>
 #include <engine/sec2.h>
@@ -977,6 +978,7 @@ acr_r352_bootstrap(struct acr_r352 *acr, struct nvkm_secboot *sb)
 {
        const struct nvkm_subdev *subdev = &sb->subdev;
        unsigned long managed_falcons = acr->base.managed_falcons;
+       u32 reg;
        int falcon_id;
        int ret;
 
@@ -1025,6 +1027,37 @@ acr_r352_bootstrap(struct acr_r352 *acr, struct nvkm_secboot *sb)
 
        /* Start LS firmware on boot falcon */
        nvkm_falcon_start(sb->boot_falcon);
+
+       /*
+        * There is a bug where the LS firmware sometimes require to be started
+        * twice (this happens only on SEC). Detect and workaround that
+        * condition.
+        *
+        * Once started, the falcon will end up in STOPPED condition (bit 5)
+        * if successful, or in HALT condition (bit 4) if not.
+        */
+       nvkm_msec(subdev->device, 1,
+                 if ((reg = nvkm_rd32(subdev->device,
+                                      sb->boot_falcon->addr + 0x100)
+                      & 0x30) != 0)
+                         break;
+       );
+       if (reg & BIT(4)) {
+               nvkm_debug(subdev, "applying workaround for start bug...");
+               nvkm_falcon_start(sb->boot_falcon);
+               nvkm_msec(subdev->device, 1,
+                       if ((reg = nvkm_rd32(subdev->device,
+                                            sb->boot_falcon->addr + 0x100)
+                            & 0x30) != 0)
+                               break;
+               );
+               if (reg & BIT(4)) {
+                       nvkm_error(subdev, "%s failed to start\n",
+                              nvkm_secboot_falcon_name[acr->base.boot_falcon]);
+                       return -EINVAL;
+               }
+       }
+
        nvkm_debug(subdev, "%s started\n",
                   nvkm_secboot_falcon_name[acr->base.boot_falcon]);