[PATCH 10/10] drm/i915/spi: add support for access mode

[Alexander Usyskin]

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

Signed-off-by: Alexander Usyskin <alexander.usyskin at intel.com>
---
 drivers/gpu/drm/i915/spi/intel_spi.c     | 25 ++++++++++++++++++++++++
 drivers/gpu/drm/i915/spi/intel_spi.h     |  1 +
 drivers/gpu/drm/i915/spi/intel_spi_drv.c |  6 +++---
 3 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/spi/intel_spi.c b/drivers/gpu/drm/i915/spi/intel_spi.c
index c697ca226e34..aac01898169f 100644
--- a/drivers/gpu/drm/i915/spi/intel_spi.c
+++ b/drivers/gpu/drm/i915/spi/intel_spi.c
@@ -9,6 +9,7 @@
 #include "spi/intel_spi.h"
 
 #define GEN12_GUNIT_SPI_SIZE 0x80
+#define HECI_FW_STATUS_2_SPI_ACCESS_MODE BIT(3)
 
 static const struct i915_spi_region regions[I915_SPI_REGIONS] = {
 	[0] = { .name = "DESCRIPTOR", },
@@ -21,6 +22,29 @@ static void i915_spi_release_dev(struct device *dev)
 {
 }
 
+static bool i915_spi_writeable_override(struct drm_i915_private *dev_priv)
+{
+	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
+	resource_size_t base;
+	bool writeable_override;
+
+	if (IS_DG1(dev_priv)) {
+		base = DG1_GSC_HECI2_BASE;
+	} else if (IS_DG2(dev_priv)) {
+		base = DG2_GSC_HECI2_BASE;
+	} else {
+		dev_err(&pdev->dev, "Unknown platform\n");
+		return true;
+	}
+
+	writeable_override =
+		!(intel_uncore_read(&dev_priv->uncore, HECI_FWSTS(base, 2)) &
+		  HECI_FW_STATUS_2_SPI_ACCESS_MODE);
+	if (writeable_override)
+		dev_info(&pdev->dev, "SPI access overridden by jumper\n");
+	return writeable_override;
+}
+
 void intel_spi_init(struct intel_spi *spi, struct drm_i915_private *dev_priv)
 {
 	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
@@ -31,6 +55,7 @@ void intel_spi_init(struct intel_spi *spi, struct drm_i915_private *dev_priv)
 	if (!IS_DGFX(dev_priv))
 		return;
 
+	spi->writeable_override = i915_spi_writeable_override(dev_priv);
 	spi->bar.parent = &pdev->resource[0];
 	spi->bar.start = GEN12_GUNIT_SPI_BASE + pdev->resource[0].start;
 	spi->bar.end = spi->bar.start + GEN12_GUNIT_SPI_SIZE - 1;
diff --git a/drivers/gpu/drm/i915/spi/intel_spi.h b/drivers/gpu/drm/i915/spi/intel_spi.h
index 1ecf1a8581b4..83588fae8c5e 100644
--- a/drivers/gpu/drm/i915/spi/intel_spi.h
+++ b/drivers/gpu/drm/i915/spi/intel_spi.h
@@ -18,6 +18,7 @@ struct i915_spi_region {
 struct intel_spi {
 	struct auxiliary_device aux_dev;
 	struct drm_i915_private *i915;
+	bool writeable_override;
 	struct resource bar;
 	const struct i915_spi_region *regions;
 };
diff --git a/drivers/gpu/drm/i915/spi/intel_spi_drv.c b/drivers/gpu/drm/i915/spi/intel_spi_drv.c
index 6b514b137fd0..75b6939ea93d 100644
--- a/drivers/gpu/drm/i915/spi/intel_spi_drv.c
+++ b/drivers/gpu/drm/i915/spi/intel_spi_drv.c
@@ -681,7 +681,7 @@ static void i915_spi_put_device(struct mtd_info *mtd)
 }
 
 static int i915_spi_init_mtd(struct i915_spi *spi, struct device *device,
-			     unsigned int nparts)
+			     unsigned int nparts, bool writeable_override)
 {
 	unsigned int i;
 	unsigned int n;
@@ -714,7 +714,7 @@ static int i915_spi_init_mtd(struct i915_spi *spi, struct device *device,
 		parts[n].name = spi->regions[i].name;
 		parts[n].offset  = spi->regions[i].offset;
 		parts[n].size = spi->regions[i].size;
-		if (!spi->regions[i].is_writable)
+		if (!spi->regions[i].is_writable && !writeable_override)
 			parts[n].mask_flags = MTD_WRITEABLE;
 		n++;
 	}
@@ -801,7 +801,7 @@ static int i915_spi_probe(struct auxiliary_device *aux_dev,
 		goto err;
 	}
 
-	ret = i915_spi_init_mtd(spi, device, ret);
+	ret = i915_spi_init_mtd(spi, device, ret, ispi->writeable_override);
 	if (ret) {
 		dev_err(device, "i915-spi failed init mtd %d\n", ret);
 		goto err;
-- 
2.34.1