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drm/i915: enable MCHBAR if needed
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Using the new PNP resource checking code, this patch allows the i915
driver to allocate MCHBAR space if needed and use the BAR to determine
current memory settings.

[apw@canonical.com: moved to the new generic PNP resource interface]
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

failure to update-index after git-am --reject to hand-apply

Signed-off-by: Eric Anholt <eric@anholt.net>
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Jesse Barnes authored and Eric Anholt committed Jun 9, 2009
1 parent 1b8e696 commit d765898
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Showing 2 changed files with 147 additions and 0 deletions.
2 changes: 2 additions & 0 deletions drivers/gpu/drm/i915/i915_drv.h
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Original file line number Diff line number Diff line change
Expand Up @@ -150,6 +150,8 @@ 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;
Expand Down
145 changes: 145 additions & 0 deletions drivers/gpu/drm/i915/i915_gem_tiling.c
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,8 @@
*
*/

#include <linux/acpi.h>
#include <linux/pnp.h>
#include "linux/string.h"
#include "linux/bitops.h"
#include "drmP.h"
Expand Down Expand Up @@ -81,6 +83,143 @@
* 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)

/* 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 &&
pnp_range_reserved(mchbar_addr, mchbar_addr + MCHBAR_SIZE)) {
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.
Expand All @@ -91,6 +230,7 @@ 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
Expand All @@ -101,6 +241,9 @@ i915_gem_detect_bit_6_swizzle(struct drm_device *dev)
} else if (IS_MOBILE(dev)) {
uint32_t dcc;

/* Try to make sure MCHBAR is enabled before poking at it */
need_disable = intel_setup_mchbar(dev);

/* On mobile 9xx chipsets, channel interleave by the CPU is
* determined by DCC. For single-channel, neither the CPU
* nor the GPU do swizzling. For dual channel interleaved,
Expand Down Expand Up @@ -140,6 +283,8 @@ i915_gem_detect_bit_6_swizzle(struct drm_device *dev)
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
Expand Down

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