x86: add early quirk for reserving Intel graphics stolen memory v5

Systems with Intel graphics controllers set aside memory exclusively for
gfx driver use.  This memory is not always marked in the E820 as
reserved or as RAM, and so is subject to overlap from E820 manipulation
later in the boot process.  On some systems, MMIO space is allocated on
top, despite the efforts of the "RAM buffer" approach, which simply
rounds memory boundaries up to 64M to try to catch space that may decode
as RAM and so is not suitable for MMIO.

v2: use read_pci_config for 32 bit reads instead of adding a new one
    (Chris)
    add gen6 stolen size function (Chris)
v3: use a function pointer (Chris)
    drop gen2 bits (Daniel)
v4: call e820_sanitize_map after adding the region
v5: fixup comments (Peter)
    simplify loop (Chris)

Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=66726
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=66844
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 154 insertions, 0 deletions

diff --git a/arch/x86/kernel/early-quirks.c b/arch/x86/kernel/early-quirks.c
index 63bdb29b2549..b3cd3ebae077 100644
--- a/arch/x86/kernel/early-quirks.c
+++ b/arch/x86/kernel/early-quirks.c
@@ -12,6 +12,7 @@
 #include <linux/pci.h>
 #include <linux/acpi.h>
 #include <linux/pci_ids.h>
+#include <drm/i915_drm.h>
 #include <asm/pci-direct.h>
 #include <asm/dma.h>
 #include <asm/io_apic.h>
@@ -216,6 +217,157 @@ static void __init intel_remapping_check(int num, int slot, int func)
 
 }
 
+/*
+ * Systems with Intel graphics controllers set aside memory exclusively
+ * for gfx driver use.  This memory is not marked in the E820 as reserved
+ * or as RAM, and so is subject to overlap from E820 manipulation later
+ * in the boot process.  On some systems, MMIO space is allocated on top,
+ * despite the efforts of the "RAM buffer" approach, which simply rounds
+ * memory boundaries up to 64M to try to catch space that may decode
+ * as RAM and so is not suitable for MMIO.
+ *
+ * And yes, so far on current devices the base addr is always under 4G.
+ */
+static u32 __init intel_stolen_base(int num, int slot, int func)
+{
+	u32 base;
+
+	/*
+	 * For the PCI IDs in this quirk, the stolen base is always
+	 * in 0x5c, aka the BDSM register (yes that's really what
+	 * it's called).
+	 */
+	base = read_pci_config(num, slot, func, 0x5c);
+	base &= ~((1<<20) - 1);
+
+	return base;
+}
+
+#define KB(x)	((x) * 1024)
+#define MB(x)	(KB (KB (x)))
+#define GB(x)	(MB (KB (x)))
+
+static size_t __init gen3_stolen_size(int num, int slot, int func)
+{
+	size_t stolen_size;
+	u16 gmch_ctrl;
+
+	gmch_ctrl = read_pci_config_16(0, 0, 0, I830_GMCH_CTRL);
+
+	switch (gmch_ctrl & I855_GMCH_GMS_MASK) {
+	case I855_GMCH_GMS_STOLEN_1M:
+		stolen_size = MB(1);
+		break;
+	case I855_GMCH_GMS_STOLEN_4M:
+		stolen_size = MB(4);
+		break;
+	case I855_GMCH_GMS_STOLEN_8M:
+		stolen_size = MB(8);
+		break;
+	case I855_GMCH_GMS_STOLEN_16M:
+		stolen_size = MB(16);
+		break;
+	case I855_GMCH_GMS_STOLEN_32M:
+		stolen_size = MB(32);
+		break;
+	case I915_GMCH_GMS_STOLEN_48M:
+		stolen_size = MB(48);
+		break;
+	case I915_GMCH_GMS_STOLEN_64M:
+		stolen_size = MB(64);
+		break;
+	case G33_GMCH_GMS_STOLEN_128M:
+		stolen_size = MB(128);
+		break;
+	case G33_GMCH_GMS_STOLEN_256M:
+		stolen_size = MB(256);
+		break;
+	case INTEL_GMCH_GMS_STOLEN_96M:
+		stolen_size = MB(96);
+		break;
+	case INTEL_GMCH_GMS_STOLEN_160M:
+		stolen_size = MB(160);
+		break;
+	case INTEL_GMCH_GMS_STOLEN_224M:
+		stolen_size = MB(224);
+		break;
+	case INTEL_GMCH_GMS_STOLEN_352M:
+		stolen_size = MB(352);
+		break;
+	default:
+		stolen_size = 0;
+		break;
+	}
+
+	return stolen_size;
+}
+
+static size_t __init gen6_stolen_size(int num, int slot, int func)
+{
+	u16 gmch_ctrl;
+
+	gmch_ctrl = read_pci_config_16(num, slot, func, SNB_GMCH_CTRL);
+	gmch_ctrl >>= SNB_GMCH_GMS_SHIFT;
+	gmch_ctrl &= SNB_GMCH_GMS_MASK;
+
+	return gmch_ctrl << 25; /* 32 MB units */
+}
+
+typedef size_t (*stolen_size_fn)(int num, int slot, int func);
+
+static struct pci_device_id intel_stolen_ids[] __initdata = {
+	INTEL_I915G_IDS(gen3_stolen_size),
+	INTEL_I915GM_IDS(gen3_stolen_size),
+	INTEL_I945G_IDS(gen3_stolen_size),
+	INTEL_I945GM_IDS(gen3_stolen_size),
+	INTEL_VLV_M_IDS(gen3_stolen_size),
+	INTEL_VLV_D_IDS(gen3_stolen_size),
+	INTEL_PINEVIEW_IDS(gen3_stolen_size),
+	INTEL_I965G_IDS(gen3_stolen_size),
+	INTEL_G33_IDS(gen3_stolen_size),
+	INTEL_I965GM_IDS(gen3_stolen_size),
+	INTEL_GM45_IDS(gen3_stolen_size),
+	INTEL_G45_IDS(gen3_stolen_size),
+	INTEL_IRONLAKE_D_IDS(gen3_stolen_size),
+	INTEL_IRONLAKE_M_IDS(gen3_stolen_size),
+	INTEL_SNB_D_IDS(gen6_stolen_size),
+	INTEL_SNB_M_IDS(gen6_stolen_size),
+	INTEL_IVB_M_IDS(gen6_stolen_size),
+	INTEL_IVB_D_IDS(gen6_stolen_size),
+	INTEL_HSW_D_IDS(gen6_stolen_size),
+	INTEL_HSW_M_IDS(gen6_stolen_size),
+};
+
+static void __init intel_graphics_stolen(int num, int slot, int func)
+{
+	size_t size;
+	int i;
+	u32 start;
+	u16 device, subvendor, subdevice;
+
+	device = read_pci_config_16(num, slot, func, PCI_DEVICE_ID);
+	subvendor = read_pci_config_16(num, slot, func,
+				       PCI_SUBSYSTEM_VENDOR_ID);
+	subdevice = read_pci_config_16(num, slot, func, PCI_SUBSYSTEM_ID);
+
+	for (i = 0; i < ARRAY_SIZE(intel_stolen_ids); i++) {
+		if (intel_stolen_ids[i].device == device) {
+			stolen_size_fn stolen_size =
+				(stolen_size_fn)intel_stolen_ids[i].driver_data;
+			size = stolen_size(num, slot, func);
+			start = intel_stolen_base(num, slot, func);
+			if (size && start) {
+				/* Mark this space as reserved */
+				e820_add_region(start, size, E820_RESERVED);
+				sanitize_e820_map(e820.map,
+						  ARRAY_SIZE(e820.map),
+						  &e820.nr_map);
+			}
+			return;
+		}
+	}
+}
+
 #define QFLAG_APPLY_ONCE 	0x1
 #define QFLAG_APPLIED		0x2
 #define QFLAG_DONE		(QFLAG_APPLY_ONCE|QFLAG_APPLIED)
@@ -251,6 +403,8 @@ static struct chipset early_qrk[] __initdata = {
 	  PCI_BASE_CLASS_BRIDGE, 0, intel_remapping_check },
 	{ PCI_VENDOR_ID_INTEL, 0x3406, PCI_CLASS_BRIDGE_HOST,
 	  PCI_BASE_CLASS_BRIDGE, 0, intel_remapping_check },
+	{ PCI_VENDOR_ID_INTEL, PCI_ANY_ID, PCI_CLASS_DISPLAY_VGA, PCI_ANY_ID,
+	  QFLAG_APPLY_ONCE, intel_graphics_stolen },
 	{}
 };