drm/xe: Carve out top of DSM as reserved

Top of DSM contains the WOPCM where kernel driver shouldn't access as
it contains data from other HW agents. Carve it out from the stolen
memory. On a MTL system, the output now matches the expected values:

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://lore.kernel.org/r/20230726160708.3967790-10-lucas.demarchi@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/xe/regs/xe_regs.h b/drivers/gpu/drm/xe/regs/xe_regs.h
index e0734c8f922c6f6e6316a256aed7b19abe2e15e0..b344796bb868ed655d5b784ecb23a92c67a432b4 100644 (file)
--- a/drivers/gpu/drm/xe/regs/xe_regs.h
+++ b/drivers/gpu/drm/xe/regs/xe_regs.h
@@ -97,4 +97,7 @@
 #define DSMBASE                                        XE_REG(0x1080C0)
 #define   BDSM_MASK                            REG_GENMASK64(63, 20)
 
+#define STOLEN_RESERVED                                XE_REG(0x1082c0)
+#define   WOPCM_SIZE_MASK                      REG_GENMASK64(8, 7)
+
 #endif

diff --git a/drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c b/drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c
index 271b3fba412965ade62a340bf3f52856e459eb96..7bba8fff5a5d9cde72abadae077e7cb01cd9b160 100644 (file)
--- a/drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c
+++ b/drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c
@@ -89,7 +89,7 @@ static s64 detect_bar2_dgfx(struct xe_device *xe, struct xe_ttm_stolen_mgr *mgr)
 static u32 detect_bar2_integrated(struct xe_device *xe, struct xe_ttm_stolen_mgr *mgr)
 {
        struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
-       u32 stolen_size;
+       u32 stolen_size, wopcm_size;
        u32 ggc, gms;
 
        ggc = xe_mmio_read32(xe_root_mmio_gt(xe), GGC);
@@ -124,6 +124,12 @@ static u32 detect_bar2_integrated(struct xe_device *xe, struct xe_ttm_stolen_mgr
                return 0;
        }
 
+       /* Carve out the top of DSM as it contains the reserved WOPCM region */
+       wopcm_size = REG_FIELD_GET64(WOPCM_SIZE_MASK,
+                                    xe_mmio_read64(xe_root_mmio_gt(xe),
+                                                   STOLEN_RESERVED));
+       stolen_size -= (1U << wopcm_size) * SZ_1M;
+
        if (drm_WARN_ON(&xe->drm, stolen_size + SZ_8M > pci_resource_len(pdev, 2)))
                return 0;