[Intel-gfx] [PATCH] allocate & enable MCHBAR if needed
Jesse Barnes
jbarnes at virtuousgeek.org
Thu Feb 12 19:57:45 CET 2009
I noticed on my Eee 901 that the i915 DRM driver wasn't reading the MCHBAR reg
at startup time, and so it would disable tiling. For decent performance,
especially on an Eee-like platform, tiling is a must. So I put this patch
together to allocate MCHBAR space and enable it if necessary.
In combination with the pre-965 tiling patches in the tree now, you should see
a big performance improvement if you have an affected machine.
This patch checks to make sure any existing MCHBAR address is ACPI reserved
before enabling, otherwise it allocates new space. This is necessary on
platforms where bridge space is tight, so a new allocation won't always work.
(Note to Eric: don't merge this until someone else confirms it works for them
too.)
Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 72b9314..a8d3256 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -143,6 +143,8 @@ typedef struct drm_i915_private {
drm_local_map_t hws_map;
struct drm_gem_object *hws_obj;
+ struct resource mch_res;
+
unsigned int cpp;
int back_offset;
int front_offset;
diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c
b/drivers/gpu/drm/i915/i915_gem_tiling.c
index 7fb4191..1dff8a3 100644
--- a/drivers/gpu/drm/i915/i915_gem_tiling.c
+++ b/drivers/gpu/drm/i915/i915_gem_tiling.c
@@ -24,6 +24,7 @@
* Eric Anholt <eric at anholt.net>
*
*/
+#include <linux/acpi.h>
#include "drmP.h"
#include "drm.h"
@@ -79,6 +80,221 @@
* to match what the GPU expects.
*/
+#define MCHBAR_I915 0x44
+#define MCHBAR_I965 0x48
+#define MCHBAR_SIZE (4*4096)
+
+#define DEVEN_REG 0x54
+#define DEVEN_MCHBAR_EN (1 << 28)
+
+/*
+ * ACPI resource checking fun. So the MCHBAR has *probably* been set
+ * up by the BIOS since drivers need to poke at it, but out of paranoia
+ * or whatever, many BIOSes disable the MCHBAR at boot. So we check
+ * to make sure any existing address is reserved before using it. If
+ * we can't find a match or there is no address, allocate some new PCI
+ * space for it, and then enable it. And of course 915 has to be different
+ * and put its enable bit somewhere else...
+ */
+static acpi_status __init check_mch_resource(struct acpi_resource *res,
+ void *data)
+{
+ struct resource *mch_res = data;
+ struct acpi_resource_address64 address;
+ acpi_status status;
+
+ if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
+ struct acpi_resource_fixed_memory32 *fixmem32 =
+ &res->data.fixed_memory32;
+ if (!fixmem32)
+ return AE_OK;
+
+ if ((mch_res->start >= fixmem32->address) &&
+ (mch_res->end < (fixmem32->address +
+ fixmem32->address_length))) {
+ mch_res->flags = 1;
+ return AE_CTRL_TERMINATE;
+ }
+ }
+ if ((res->type != ACPI_RESOURCE_TYPE_ADDRESS32) &&
+ (res->type != ACPI_RESOURCE_TYPE_ADDRESS64))
+ return AE_OK;
+
+ status = acpi_resource_to_address64(res, &address);
+ if (ACPI_FAILURE(status) ||
+ (address.address_length <= 0) ||
+ (address.resource_type != ACPI_MEMORY_RANGE))
+ return AE_OK;
+
+ if ((mch_res->start >= address.minimum) &&
+ (mch_res->end < (address.minimum + address.address_length))) {
+ mch_res->flags = 1;
+ return AE_CTRL_TERMINATE;
+ }
+ return AE_OK;
+}
+
+static acpi_status __init find_mboard_resource(acpi_handle handle, u32 lvl,
+ void *context, void **rv)
+{
+ struct resource *mch_res = context;
+
+ acpi_walk_resources(handle, METHOD_NAME__CRS,
+ check_mch_resource, context);
+
+ if (mch_res->flags)
+ return AE_CTRL_TERMINATE;
+
+ return AE_OK;
+}
+
+static int __init is_acpi_reserved(u64 start, u64 end, unsigned not_used)
+{
+ struct resource mch_res;
+
+ mch_res.start = start;
+ mch_res.end = end;
+ mch_res.flags = 0;
+
+ acpi_get_devices("PNP0C01", find_mboard_resource, &mch_res, NULL);
+
+ if (!mch_res.flags)
+ acpi_get_devices("PNP0C02", find_mboard_resource, &mch_res,
+ NULL);
+
+ return mch_res.flags;
+}
+
+/* Allocate space for the MCH regs if needed, return nonzero on error */
+static int
+intel_alloc_mchbar_resource(struct drm_device *dev)
+{
+ struct pci_dev *bridge_dev;
+ drm_i915_private_t *dev_priv = dev->dev_private;
+ int reg = IS_I965G(dev) ? MCHBAR_I965 : MCHBAR_I915;
+ u32 temp_lo, temp_hi = 0;
+ u64 mchbar_addr;
+ int ret = 0;
+
+ bridge_dev = pci_get_bus_and_slot(0, PCI_DEVFN(0,0));
+ if (!bridge_dev) {
+ DRM_DEBUG("no bridge dev?!\n");
+ ret = -ENODEV;
+ goto out;
+ }
+
+ if (IS_I965G(dev))
+ pci_read_config_dword(bridge_dev, reg + 4, &temp_hi);
+ pci_read_config_dword(bridge_dev, reg, &temp_lo);
+ mchbar_addr = ((u64)temp_hi << 32) | temp_lo;
+
+ /* If ACPI doesn't have it, assume we need to allocate it ourselves */
+ if (mchbar_addr &&
+ is_acpi_reserved(mchbar_addr, mchbar_addr + MCHBAR_SIZE, 0)) {
+ ret = 0;
+ goto out_put;
+ }
+
+ /* Get some space for it */
+ ret = pci_bus_alloc_resource(bridge_dev->bus, &dev_priv->mch_res,
+ MCHBAR_SIZE, MCHBAR_SIZE,
+ PCIBIOS_MIN_MEM,
+ 0, pcibios_align_resource,
+ bridge_dev);
+ if (ret) {
+ DRM_DEBUG("failed bus alloc: %d\n", ret);
+ dev_priv->mch_res.start = 0;
+ goto out_put;
+ }
+
+ if (IS_I965G(dev))
+ pci_write_config_dword(bridge_dev, reg + 4,
+ upper_32_bits(dev_priv->mch_res.start));
+
+ pci_write_config_dword(bridge_dev, reg,
+ lower_32_bits(dev_priv->mch_res.start));
+out_put:
+ pci_dev_put(bridge_dev);
+out:
+ return ret;
+}
+
+/* Setup MCHBAR if possible, return true if we should disable it again */
+static bool
+intel_setup_mchbar(struct drm_device *dev)
+{
+ struct pci_dev *bridge_dev;
+ int mchbar_reg = IS_I965G(dev) ? MCHBAR_I965 : MCHBAR_I915;
+ u32 temp;
+ bool need_disable = false, enabled;
+
+ bridge_dev = pci_get_bus_and_slot(0, PCI_DEVFN(0,0));
+ if (!bridge_dev) {
+ DRM_DEBUG("no bridge dev?!\n");
+ goto out;
+ }
+
+ if (IS_I915G(dev) || IS_I915GM(dev)) {
+ pci_read_config_dword(bridge_dev, DEVEN_REG, &temp);
+ enabled = !!(temp & DEVEN_MCHBAR_EN);
+ } else {
+ pci_read_config_dword(bridge_dev, mchbar_reg, &temp);
+ enabled = temp & 1;
+ }
+
+ /* If it's already enabled, don't have to do anything */
+ if (enabled)
+ goto out_put;
+
+ if (intel_alloc_mchbar_resource(dev))
+ goto out_put;
+
+ need_disable = true;
+
+ /* Space is allocated or reserved, so enable it. */
+ if (IS_I915G(dev) || IS_I915GM(dev)) {
+ pci_write_config_dword(bridge_dev, DEVEN_REG,
+ temp | DEVEN_MCHBAR_EN);
+ } else {
+ pci_read_config_dword(bridge_dev, mchbar_reg, &temp);
+ pci_write_config_dword(bridge_dev, mchbar_reg, temp | 1);
+ }
+out_put:
+ pci_dev_put(bridge_dev);
+out:
+ return need_disable;
+}
+
+static void
+intel_teardown_mchbar(struct drm_device *dev, bool disable)
+{
+ drm_i915_private_t *dev_priv = dev->dev_private;
+ struct pci_dev *bridge_dev;
+ int mchbar_reg = IS_I965G(dev) ? MCHBAR_I965 : MCHBAR_I915;
+ u32 temp;
+
+ bridge_dev = pci_get_bus_and_slot(0, PCI_DEVFN(0,0));
+ if (!bridge_dev) {
+ DRM_DEBUG("no bridge dev?!\n");
+ return;
+ }
+
+ if (disable) {
+ if (IS_I915G(dev) || IS_I915GM(dev)) {
+ pci_read_config_dword(bridge_dev, DEVEN_REG, &temp);
+ temp &= ~DEVEN_MCHBAR_EN;
+ pci_write_config_dword(bridge_dev, DEVEN_REG, temp);
+ } else {
+ pci_read_config_dword(bridge_dev, mchbar_reg, &temp);
+ temp &= ~1;
+ pci_write_config_dword(bridge_dev, mchbar_reg, temp);
+ }
+ }
+
+ if (dev_priv->mch_res.start)
+ release_resource(&dev_priv->mch_res);
+}
+
/**
* Detects bit 6 swizzling of address lookup between IGD access and CPU
* access through main memory.
@@ -89,6 +305,7 @@ i915_gem_detect_bit_6_swizzle(struct drm_device *dev)
drm_i915_private_t *dev_priv = dev->dev_private;
uint32_t swizzle_x = I915_BIT_6_SWIZZLE_UNKNOWN;
uint32_t swizzle_y = I915_BIT_6_SWIZZLE_UNKNOWN;
+ bool need_disable;
if (!IS_I9XX(dev)) {
/* As far as we know, the 865 doesn't have these bit 6
@@ -100,6 +317,9 @@ i915_gem_detect_bit_6_swizzle(struct drm_device *dev)
IS_GM45(dev)) {
uint32_t dcc;
+ /* Try to make sure MCHBAR is enabled before poking at it */
+ need_disable = intel_setup_mchbar(dev);
+
/* On 915-945 and GM965, channel interleave by the CPU is
* determined by DCC. The CPU will alternate based on bit 6
* in interleaved mode, and the GPU will then also alternate
@@ -134,11 +354,11 @@ i915_gem_detect_bit_6_swizzle(struct drm_device *dev)
break;
}
if (dcc == 0xffffffff) {
- DRM_ERROR("Couldn't read from MCHBAR. "
- "Disabling tiling.\n");
swizzle_x = I915_BIT_6_SWIZZLE_UNKNOWN;
swizzle_y = I915_BIT_6_SWIZZLE_UNKNOWN;
}
+
+ intel_teardown_mchbar(dev, need_disable);
} else {
/* The 965, G33, and newer, have a very flexible memory
* configuration. It will enable dual-channel mode
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