drm/i915: nuke the duplicated stolen discovery

We duplicate the stolen discovery code in early-quirks and in i915,
however now that the stolen region is exported as a resource from
early-quirks we can nuke the duplication.

v2: check overflows_type

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171211151822.20953-5-matthew.auld@intel.com

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -2949,50 +2949,6 @@ static unsigned int chv_get_total_gtt_size(u16 gmch_ctrl)
 	return 0;
 }
 
-static size_t gen6_get_stolen_size(u16 snb_gmch_ctl)
-{
-	snb_gmch_ctl >>= SNB_GMCH_GMS_SHIFT;
-	snb_gmch_ctl &= SNB_GMCH_GMS_MASK;
-	return (size_t)snb_gmch_ctl << 25; /* 32 MB units */
-}
-
-static size_t gen8_get_stolen_size(u16 bdw_gmch_ctl)
-{
-	bdw_gmch_ctl >>= BDW_GMCH_GMS_SHIFT;
-	bdw_gmch_ctl &= BDW_GMCH_GMS_MASK;
-	return (size_t)bdw_gmch_ctl << 25; /* 32 MB units */
-}
-
-static size_t chv_get_stolen_size(u16 gmch_ctrl)
-{
-	gmch_ctrl >>= SNB_GMCH_GMS_SHIFT;
-	gmch_ctrl &= SNB_GMCH_GMS_MASK;
-
-	/*
-	 * 0x0  to 0x10: 32MB increments starting at 0MB
-	 * 0x11 to 0x16: 4MB increments starting at 8MB
-	 * 0x17 to 0x1d: 4MB increments start at 36MB
-	 */
-	if (gmch_ctrl < 0x11)
-		return (size_t)gmch_ctrl << 25;
-	else if (gmch_ctrl < 0x17)
-		return (size_t)(gmch_ctrl - 0x11 + 2) << 22;
-	else
-		return (size_t)(gmch_ctrl - 0x17 + 9) << 22;
-}
-
-static size_t gen9_get_stolen_size(u16 gen9_gmch_ctl)
-{
-	gen9_gmch_ctl >>= BDW_GMCH_GMS_SHIFT;
-	gen9_gmch_ctl &= BDW_GMCH_GMS_MASK;
-
-	if (gen9_gmch_ctl < 0xf0)
-		return (size_t)gen9_gmch_ctl << 25; /* 32 MB units */
-	else
-		/* 4MB increments starting at 0xf0 for 4MB */
-		return (size_t)(gen9_gmch_ctl - 0xf0 + 1) << 22;
-}
-
 static int ggtt_probe_common(struct i915_ggtt *ggtt, u64 size)
 {
 	struct drm_i915_private *dev_priv = ggtt->base.i915;
@@ -3343,14 +3299,13 @@ static int gen8_gmch_probe(struct i915_ggtt *ggtt)
 
 	pci_read_config_word(pdev, SNB_GMCH_CTRL, &snb_gmch_ctl);
 
+	ggtt->stolen_size = resource_size(&intel_graphics_stolen_res);
+
 	if (INTEL_GEN(dev_priv) >= 9) {
-		ggtt->stolen_size = gen9_get_stolen_size(snb_gmch_ctl);
 		size = gen8_get_total_gtt_size(snb_gmch_ctl);
 	} else if (IS_CHERRYVIEW(dev_priv)) {
-		ggtt->stolen_size = chv_get_stolen_size(snb_gmch_ctl);
 		size = chv_get_total_gtt_size(snb_gmch_ctl);
 	} else {
-		ggtt->stolen_size = gen8_get_stolen_size(snb_gmch_ctl);
 		size = gen8_get_total_gtt_size(snb_gmch_ctl);
 	}
 
@@ -3408,7 +3363,7 @@ static int gen6_gmch_probe(struct i915_ggtt *ggtt)
 		DRM_ERROR("Can't set DMA mask/consistent mask (%d)\n", err);
 	pci_read_config_word(pdev, SNB_GMCH_CTRL, &snb_gmch_ctl);
 
-	ggtt->stolen_size = gen6_get_stolen_size(snb_gmch_ctl);
+	ggtt->stolen_size = resource_size(&intel_graphics_stolen_res);
 
 	size = gen6_get_total_gtt_size(snb_gmch_ctl);
 	ggtt->base.total = (size / sizeof(gen6_pte_t)) << PAGE_SHIFT;

drivers/gpu/drm/i915/i915_gem_stolen.c

@@ -30,9 +30,6 @@
 #include <drm/i915_drm.h>
 #include "i915_drv.h"
 
-#define KB(x) ((x) * 1024)
-#define MB(x) (KB(x) * 1024)
-
 /*
  * The BIOS typically reserves some of the system's memory for the exclusive
  * use of the integrated graphics. This memory is no longer available for
@@ -81,113 +78,11 @@ void i915_gem_stolen_remove_node(struct drm_i915_private *dev_priv,
 
 static dma_addr_t i915_stolen_to_dma(struct drm_i915_private *dev_priv)
 {
-	struct pci_dev *pdev = dev_priv->drm.pdev;
 	struct i915_ggtt *ggtt = &dev_priv->ggtt;
+	dma_addr_t base = intel_graphics_stolen_res.start;
 	struct resource *r;
-	dma_addr_t base;
-
-	/* Almost universally we can find the Graphics Base of Stolen Memory
-	 * at register BSM (0x5c) in the igfx configuration space. On a few
-	 * (desktop) machines this is also mirrored in the bridge device at
-	 * different locations, or in the MCHBAR.
-	 *
-	 * On 865 we just check the TOUD register.
-	 *
-	 * On 830/845/85x the stolen memory base isn't available in any
-	 * register. We need to calculate it as TOM-TSEG_SIZE-stolen_size.
-	 *
-	 */
-	base = 0;
-	if (INTEL_GEN(dev_priv) >= 3) {
-		u32 bsm;
-
-		pci_read_config_dword(pdev, INTEL_BSM, &bsm);
-
-		base = bsm & INTEL_BSM_MASK;
-	} else if (IS_I865G(dev_priv)) {
-		u32 tseg_size = 0;
-		u16 toud = 0;
-		u8 tmp;
-
-		pci_bus_read_config_byte(pdev->bus, PCI_DEVFN(0, 0),
-					 I845_ESMRAMC, &tmp);
-
-		if (tmp & TSEG_ENABLE) {
-			switch (tmp & I845_TSEG_SIZE_MASK) {
-			case I845_TSEG_SIZE_512K:
-				tseg_size = KB(512);
-				break;
-			case I845_TSEG_SIZE_1M:
-				tseg_size = MB(1);
-				break;
-			}
-		}
-
-		pci_bus_read_config_word(pdev->bus, PCI_DEVFN(0, 0),
-					 I865_TOUD, &toud);
-
-		base = (toud << 16) + tseg_size;
-	} else if (IS_I85X(dev_priv)) {
-		u32 tseg_size = 0;
-		u32 tom;
-		u8 tmp;
-
-		pci_bus_read_config_byte(pdev->bus, PCI_DEVFN(0, 0),
-					 I85X_ESMRAMC, &tmp);
-
-		if (tmp & TSEG_ENABLE)
-			tseg_size = MB(1);
-
-		pci_bus_read_config_byte(pdev->bus, PCI_DEVFN(0, 1),
-					 I85X_DRB3, &tmp);
-		tom = tmp * MB(32);
-
-		base = tom - tseg_size - ggtt->stolen_size;
-	} else if (IS_I845G(dev_priv)) {
-		u32 tseg_size = 0;
-		u32 tom;
-		u8 tmp;
-
-		pci_bus_read_config_byte(pdev->bus, PCI_DEVFN(0, 0),
-					 I845_ESMRAMC, &tmp);
-
-		if (tmp & TSEG_ENABLE) {
-			switch (tmp & I845_TSEG_SIZE_MASK) {
-			case I845_TSEG_SIZE_512K:
-				tseg_size = KB(512);
-				break;
-			case I845_TSEG_SIZE_1M:
-				tseg_size = MB(1);
-				break;
-			}
-		}
-
-		pci_bus_read_config_byte(pdev->bus, PCI_DEVFN(0, 0),
-					 I830_DRB3, &tmp);
-		tom = tmp * MB(32);
 
-		base = tom - tseg_size - ggtt->stolen_size;
-	} else if (IS_I830(dev_priv)) {
-		u32 tseg_size = 0;
-		u32 tom;
-		u8 tmp;
-
-		pci_bus_read_config_byte(pdev->bus, PCI_DEVFN(0, 0),
-					 I830_ESMRAMC, &tmp);
-
-		if (tmp & TSEG_ENABLE) {
-			if (tmp & I830_TSEG_SIZE_1M)
-				tseg_size = MB(1);
-			else
-				tseg_size = KB(512);
-		}
-
-		pci_bus_read_config_byte(pdev->bus, PCI_DEVFN(0, 0),
-					 I830_DRB3, &tmp);
-		tom = tmp * MB(32);
-
-		base = tom - tseg_size - ggtt->stolen_size;
-	}
+	GEM_BUG_ON(overflows_type(intel_graphics_stolen_res.start, base));
 
 	if (base == 0 || add_overflows(base, ggtt->stolen_size))
 		return 0;