linux-kernel - Re: [PATCH v2 10/10] intel-gtt: Read 64bit for gmar_bus

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Date:	Fri, 20 Dec 2013 17:19:38 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	Bjorn Helgaas <bhelgaas@...gle.com>
Cc:	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Gu Zheng <guz.fnst@...fujitsu.com>,
	Guo Chao <yan@...ux.vnet.ibm.com>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	David Airlie <airlied@...ux.ie>
Subject: Re: [PATCH v2 10/10] intel-gtt: Read 64bit for gmar_bus_addr

On Fri, Dec 20, 2013 at 4:27 PM, Bjorn Helgaas <bhelgaas@...gle.com> wrote:

> Why are we reading these BARs directly anyway?  These look like
> standard PCI BARs (I810_GMADDR == 0x10 and I915_GMADDR == 0x18), so
> the PCI core should already be reading them correctly, shouldn't it?
> Can't we just use pcibios_resource_to_bus(pci_resource_start())?
>
> It looks like i810_setup(), i830_setup(), and i9xx_setup() have the
> same problem and should also be using pci_resource_start() or
> something similar.

Agreed.

should be sth like:


Index: linux-2.6/drivers/char/agp/intel-gtt.c
===================================================================
--- linux-2.6.orig/drivers/char/agp/intel-gtt.c
+++ linux-2.6/drivers/char/agp/intel-gtt.c
@@ -608,9 +608,9 @@ static bool intel_gtt_can_wc(void)

 static int intel_gtt_init(void)
 {
-       u32 gma_addr;
+       struct pci_bus_region r;
        u32 gtt_map_size;
-       int ret;
+       int ret, idx;

        ret = intel_private.driver->setup();
        if (ret != 0)
@@ -660,13 +660,14 @@ static int intel_gtt_init(void)
        }

        if (INTEL_GTT_GEN <= 2)
-               pci_read_config_dword(intel_private.pcidev, I810_GMADDR,
-                                     &gma_addr);
+               idx = 0; /* I810_GMADDR */
        else
-               pci_read_config_dword(intel_private.pcidev, I915_GMADDR,
-                                     &gma_addr);
+               idx = 2; /* I915_GMADDR */

-       intel_private.gma_bus_addr = (gma_addr & PCI_BASE_ADDRESS_MEM_MASK);
+       pcibios_resource_to_bus(intel_private.pcidev->bus, &r,
+                               &intel_private.pcidev->resource[idx]);
+
+       intel_private.gma_bus_addr = r.start;

        return 0;
 }

View attachment "intel_gma_bus_addr_resource_bus.patch" of type "text/x-patch" (965 bytes)