When trying to test my CONFIG_IO_STRICT_DEVMEM changes I realized they
do nothing for i915. Because i915 doesn't request any regions, like
pretty much all drm pci drivers. I guess this is some very old
remnants from the userspace modesetting days, when we wanted to
co-exist with the fbdev driver. Which usually requested these
resources.

But makes me wonder why the pci subsystem doesn't just request
resource automatically when we map a bar and a pci driver is bound?

Knowledge about which pci bars we need kludged together from
intel_uncore.c and intel_gtt.c from i915 and intel-gtt.c over in the
fake agp driver.

Signed-off-by: Daniel Vetter <daniel.vet...@intel.com>
Cc: Jason Gunthorpe <j...@ziepe.ca>
Cc: Kees Cook <keesc...@chromium.org>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: John Hubbard <jhubb...@nvidia.com>
Cc: Jérôme Glisse <jgli...@redhat.com>
Cc: Jan Kara <j...@suse.cz>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: linux...@kvack.org
Cc: linux-arm-ker...@lists.infradead.org
Cc: linux-samsung-...@vger.kernel.org
Cc: linux-me...@vger.kernel.org
Cc: Bjorn Helgaas <bhelg...@google.com>
Cc: linux-...@vger.kernel.org
---
 drivers/gpu/drm/i915/intel_uncore.c | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_uncore.c 
b/drivers/gpu/drm/i915/intel_uncore.c
index 54e201fdeba4..ce39049d8919 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -1692,10 +1692,13 @@ static int uncore_mmio_setup(struct intel_uncore 
*uncore)
        struct pci_dev *pdev = i915->drm.pdev;
        int mmio_bar;
        int mmio_size;
+       int bar_selection;
+       int ret;
 
        mmio_bar = IS_GEN(i915, 2) ? 1 : 0;
+       bar_selection = BIT (2) | BIT(mmio_bar);
        /*
-        * Before gen4, the registers and the GTT are behind different BARs.
+        * On gen3 the registers and the GTT are behind different BARs.
         * However, from gen4 onwards, the registers and the GTT are shared
         * in the same BAR, so we want to restrict this ioremap from
         * clobbering the GTT which we want ioremap_wc instead. Fortunately,
@@ -1703,6 +1706,8 @@ static int uncore_mmio_setup(struct intel_uncore *uncore)
         * generations up to Ironlake.
         * For dgfx chips register range is expanded to 4MB.
         */
+       if (INTEL_GEN(i915) == 3)
+               bar_selection |= BIT(3);
        if (INTEL_GEN(i915) < 5)
                mmio_size = 512 * 1024;
        else if (IS_DGFX(i915))
@@ -1710,8 +1715,15 @@ static int uncore_mmio_setup(struct intel_uncore *uncore)
        else
                mmio_size = 2 * 1024 * 1024;
 
+       ret = pci_request_selected_regions(pdev, bar_selection, "i915");
+       if (ret < 0) {
+               drm_err(&i915->drm, "failed to request pci bars\n");
+               return ret;
+       }
+
        uncore->regs = pci_iomap(pdev, mmio_bar, mmio_size);
        if (uncore->regs == NULL) {
+               pci_release_selected_regions(pdev, bar_selection);
                drm_err(&i915->drm, "failed to map registers\n");
                return -EIO;
        }
@@ -1721,9 +1733,18 @@ static int uncore_mmio_setup(struct intel_uncore *uncore)
 
 static void uncore_mmio_cleanup(struct intel_uncore *uncore)
 {
-       struct pci_dev *pdev = uncore->i915->drm.pdev;
+       struct drm_i915_private *i915 = uncore->i915;
+       struct pci_dev *pdev = i915->drm.pdev;
+       int mmio_bar;
+       int bar_selection;
+
+       mmio_bar = IS_GEN(i915, 2) ? 1 : 0;
+       bar_selection = BIT (2) | BIT(mmio_bar);
+       if (INTEL_GEN(i915) == 3)
+               bar_selection |= BIT(3);
 
        pci_iounmap(pdev, uncore->regs);
+       pci_release_selected_regions(pdev, bar_selection);
 }
 
 void intel_uncore_init_early(struct intel_uncore *uncore,
-- 
2.28.0

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