[PATCH v4 09/11] drm/i915/nvm: add support for access mode

[Alexander Usyskin]

Check NVM access mode from GSC FW status registers
and overwrite access status read from SPI descriptor, if needed.

Reviewed-by: Rodrigo Vivi <rodrigo.v...@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usys...@intel.com>
---
 drivers/gpu/drm/i915/intel_nvm.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_nvm.c b/drivers/gpu/drm/i915/intel_nvm.c
index 75d3ebe669ff..d88f8b9b5ace 100644
--- a/drivers/gpu/drm/i915/intel_nvm.c
+++ b/drivers/gpu/drm/i915/intel_nvm.c
@@ -10,6 +10,7 @@
 #include "intel_nvm.h"
 
 #define GEN12_GUNIT_NVM_SIZE 0x80
+#define HECI_FW_STATUS_2_NVM_ACCESS_MODE BIT(3)
 
 static const struct intel_dg_nvm_region regions[INTEL_DG_NVM_REGIONS] = {
        [0] = { .name = "DESCRIPTOR", },
@@ -22,6 +23,28 @@ static void i915_nvm_release_dev(struct device *dev)
 {
 }
 
+static bool i915_nvm_writeable_override(struct drm_i915_private *i915)
+{
+       resource_size_t base;
+       bool writeable_override;
+
+       if (IS_DG1(i915)) {
+               base = DG1_GSC_HECI2_BASE;
+       } else if (IS_DG2(i915)) {
+               base = DG2_GSC_HECI2_BASE;
+       } else {
+               drm_err(&i915->drm, "Unknown platform\n");
+               return true;
+       }
+
+       writeable_override =
+               !(intel_uncore_read(&i915->uncore, HECI_FWSTS(base, 2)) &
+                 HECI_FW_STATUS_2_NVM_ACCESS_MODE);
+       if (writeable_override)
+               drm_info(&i915->drm, "NVM access overridden by jumper\n");
+       return writeable_override;
+}
+
 void intel_nvm_init(struct drm_i915_private *i915)
 {
        struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
@@ -43,7 +66,7 @@ void intel_nvm_init(struct drm_i915_private *i915)
 
        nvm = i915->nvm;
 
-       nvm->writeable_override = true;
+       nvm->writeable_override = i915_nvm_writeable_override(i915);
        nvm->bar.parent = &pdev->resource[0];
        nvm->bar.start = GEN12_GUNIT_NVM_BASE + pdev->resource[0].start;
        nvm->bar.end = nvm->bar.start + GEN12_GUNIT_NVM_SIZE - 1;
-- 
2.43.0