On Thu, 16 Jun 2022, priyanka.dandamudi@xxxxxxxxx wrote: > From: Akeem G Abodunrin <akeem.g.abodunrin@xxxxxxxxx> > > Add support for the local memory PICe resizable bar, so that > local memory can be resized to the maximum size supported by the device, > and mapped correctly to the PCIe memory bar. It is usual that GPU > devices expose only 256MB BARs primarily to be compatible with 32-bit > systems. So, those devices cannot claim larger memory BAR windows size due > to the system BIOS limitation. With this change, it would be possible to > reprogram the windows of the bridge directly above the requesting device > on the same BAR type. > > Signed-off-by: Akeem G Abodunrin <akeem.g.abodunrin@xxxxxxxxx> > Signed-off-by: Michał Winiarski <michal.winiarski@xxxxxxxxx> > Cc: Stuart Summers <stuart.summers@xxxxxxxxx> > Cc: Michael J Ruhl <michael.j.ruhl@xxxxxxxxx> > Cc: Prathap Kumar Valsan <prathap.kumar.valsan@xxxxxxxxx> > Signed-off-by: Priyanka Dandamudi <priyanka.dandamudi@xxxxxxxxx> > Reviewed-by: Matthew Auld <matthew.auld@xxxxxxxxx> Please see https://lore.kernel.org/r/87pmj8vesm.fsf@xxxxxxxxx > --- > drivers/gpu/drm/i915/i915_driver.c | 92 ++++++++++++++++++++++++++++++ > 1 file changed, 92 insertions(+) > > diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c > index d26dcca7e654..4bdb471cb2e2 100644 > --- a/drivers/gpu/drm/i915/i915_driver.c > +++ b/drivers/gpu/drm/i915/i915_driver.c > @@ -303,6 +303,95 @@ static void sanitize_gpu(struct drm_i915_private *i915) > __intel_gt_reset(to_gt(i915), ALL_ENGINES); > } > > +static void __release_bars(struct pci_dev *pdev) > +{ > + int resno; > + > + for (resno = PCI_STD_RESOURCES; resno < PCI_STD_RESOURCE_END; resno++) { > + if (pci_resource_len(pdev, resno)) > + pci_release_resource(pdev, resno); > + } > +} > + > +static void > +__resize_bar(struct drm_i915_private *i915, int resno, resource_size_t size) > +{ > + struct pci_dev *pdev = to_pci_dev(i915->drm.dev); > + int bar_size = pci_rebar_bytes_to_size(size); > + int ret; > + > + __release_bars(pdev); > + > + ret = pci_resize_resource(pdev, resno, bar_size); > + if (ret) { > + drm_info(&i915->drm, "Failed to resize BAR%d to %dM (%pe)\n", > + resno, 1 << bar_size, ERR_PTR(ret)); > + return; > + } > + > + drm_info(&i915->drm, "BAR%d resized to %dM\n", resno, 1 << bar_size); > +} > + > +/* BAR size starts from 1MB - 2^20 */ > +#define BAR_SIZE_SHIFT 20 > +static resource_size_t > +__lmem_rebar_size(struct drm_i915_private *i915, int resno) > +{ > + struct pci_dev *pdev = to_pci_dev(i915->drm.dev); > + u32 rebar = pci_rebar_get_possible_sizes(pdev, resno); > + resource_size_t size; > + > + if (!rebar) > + return 0; > + > + size = 1ULL << (__fls(rebar) + BAR_SIZE_SHIFT); > + > + if (size <= pci_resource_len(pdev, resno)) > + return 0; > + > + return size; > +} > + > +#define LMEM_BAR_NUM 2 > +static void i915_resize_lmem_bar(struct drm_i915_private *i915) > +{ > + struct pci_dev *pdev = to_pci_dev(i915->drm.dev); > + struct pci_bus *root = pdev->bus; > + struct resource *root_res; > + resource_size_t rebar_size = __lmem_rebar_size(i915, LMEM_BAR_NUM); > + u32 pci_cmd; > + int i; > + > + if (!rebar_size) > + return; > + > + /* Find out if root bus contains 64bit memory addressing */ > + while (root->parent) > + root = root->parent; > + > + pci_bus_for_each_resource(root, root_res, i) { > + if (root_res && root_res->flags & (IORESOURCE_MEM | > + IORESOURCE_MEM_64) && root_res->start > 0x100000000ull) > + break; > + } > + > + /* pci_resize_resource will fail anyways */ > + if (!root_res) { > + drm_info(&i915->drm, "Can't resize LMEM BAR - platform support is missing\n"); > + return; > + } > + > + /* First disable PCI memory decoding references */ > + pci_read_config_dword(pdev, PCI_COMMAND, &pci_cmd); > + pci_write_config_dword(pdev, PCI_COMMAND, > + pci_cmd & ~PCI_COMMAND_MEMORY); > + > + __resize_bar(i915, LMEM_BAR_NUM, rebar_size); > + > + pci_assign_unassigned_bus_resources(pdev->bus); > + pci_write_config_dword(pdev, PCI_COMMAND, pci_cmd); > +} > + > /** > * i915_driver_early_probe - setup state not requiring device access > * @dev_priv: device private > @@ -852,6 +941,9 @@ int i915_driver_probe(struct pci_dev *pdev, const struct pci_device_id *ent) > > disable_rpm_wakeref_asserts(&i915->runtime_pm); > > + if (HAS_LMEM(i915)) > + i915_resize_lmem_bar(i915); > + > intel_vgpu_detect(i915); > > ret = intel_gt_probe_all(i915); -- Jani Nikula, Intel Open Source Graphics Center
