[PATCH] PCI/VGA: Fixup the firmware fb address om demanding time

[Sui Jingfeng]

Currently, the vga_is_firmware_default() function works on x86 and IA64
architecture only, it is a no-op on ARM64/PPC/RISC-V arch etc. This patch
complete the implementation for the non-x86 architectures by tracking the
firmware fb's address range. Which overcome the VRAM bar relocation issue
by updating the cached firmware fb address range on demanding time.

This make the vga_is_firmware_default() function works on whatever archs
who has UEFI GOP support.

Signed-off-by: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>
---
 drivers/pci/vgaarb.c | 139 ++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 124 insertions(+), 15 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index 5a696078b382..8d5c7ee4ee7b 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -61,6 +61,84 @@ static bool vga_arbiter_used;
 static DEFINE_SPINLOCK(vga_lock);
 static DECLARE_WAIT_QUEUE_HEAD(vga_wait_queue);
 
+static struct firmware_fb_tracker {
+	/* The PCI(e) device who owns the firmware framebuffer */
+	struct pci_dev *pdev;
+	/* The index of the VRAM Bar */
+	unsigned int bar;
+	/* Firmware fb's offset from the VRAM aperture start */
+	resource_size_t offset;
+	/* The firmware fb's size, in bytes */
+	resource_size_t size;
+
+	/* Firmware fb's address range, suffer from change */
+	resource_size_t start;
+	resource_size_t end;
+
+} firmware_fb;
+
+static bool vga_arb_get_fb_range_from_screen_info(resource_size_t *start,
+						  resource_size_t *end)
+{
+	resource_size_t fb_start;
+	resource_size_t fb_end;
+	resource_size_t fb_size;
+
+	fb_start = screen_info.lfb_base;
+	if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
+		fb_start |= (u64)screen_info.ext_lfb_base << 32;
+
+	fb_size = screen_info.lfb_size;
+
+	/* No firmware framebuffer support */
+	if (!fb_start || !fb_size)
+		return false;
+
+	fb_end = fb_start + fb_size - 1;
+
+	*start = fb_start;
+	*end = fb_end;
+
+	return true;
+}
+
+static bool vga_arb_get_fb_range_from_tracker(resource_size_t *start,
+					      resource_size_t *end)
+{
+	struct pci_dev *pdev = firmware_fb.pdev;
+	resource_size_t new_vram_base;
+	resource_size_t new_fb_start;
+	resource_size_t old_fb_start;
+	resource_size_t old_fb_end;
+
+	/*
+	 * No firmware framebuffer support or No aperture that contains the
+	 * firmware FB is found, in this case, the firmware_fb.pdev will be
+	 * NULL. We will return immediately.
+	 */
+	if (!pdev)
+		return false;
+
+	new_vram_base = pdev->resource[firmware_fb.bar].start;
+	new_fb_start = new_vram_base + firmware_fb.offset;
+	old_fb_start = firmware_fb.start;
+	old_fb_end = firmware_fb.end;
+
+	if (new_fb_start != old_fb_start) {
+		firmware_fb.start = new_fb_start;
+		firmware_fb.end = new_fb_start + firmware_fb.size - 1;
+		/* Firmware fb address range moved */
+		vgaarb_dbg(&pdev->dev,
+			   "[0x%llx, 0x%llx] -> [0x%llx, 0x%llx]\n",
+			   old_fb_start, old_fb_end,
+			   firmware_fb.start, firmware_fb.end);
+	}
+
+	*start = firmware_fb.start;
+	*end = firmware_fb.end;
+
+	return true;
+}
 
 static const char *vga_iostate_to_str(unsigned int iostate)
 {
@@ -543,20 +621,21 @@ void vga_put(struct pci_dev *pdev, unsigned int rsrc)
 }
 EXPORT_SYMBOL(vga_put);
 
+/* Select the device owning the boot framebuffer if there is one */
 static bool vga_is_firmware_default(struct pci_dev *pdev)
 {
-#if defined(CONFIG_X86) || defined(CONFIG_IA64)
-	u64 base = screen_info.lfb_base;
-	u64 size = screen_info.lfb_size;
 	struct resource *r;
-	u64 limit;
+	resource_size_t fb_start;
+	resource_size_t fb_end;
+	bool ret;
 
-	/* Select the device owning the boot framebuffer if there is one */
-
-	if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
-		base |= (u64)screen_info.ext_lfb_base << 32;
-
-	limit = base + size;
+#if defined(CONFIG_X86) || defined(CONFIG_IA64)
+	ret = vga_arb_get_fb_range_from_screen_info(&fb_start, &fb_end);
+#else
+	ret = vga_arb_get_fb_range_from_tracker(&fb_start, &fb_end);
+#endif
+	if (!ret)
+		return false;
 
 	/* Does firmware framebuffer belong to us? */
 	pci_dev_for_each_resource(pdev, r) {
@@ -566,12 +645,10 @@ static bool vga_is_firmware_default(struct pci_dev *pdev)
 		if (!r->start || !r->end)
 			continue;
 
-		if (base < r->start || limit >= r->end)
-			continue;
-
-		return true;
+		if (fb_start >= r->start && fb_end <= r->end)
+			return true;
 	}
-#endif
+
 	return false;
 }
 
@@ -1555,3 +1632,35 @@ static int __init vga_arb_device_init(void)
 	return rc;
 }
 subsys_initcall_sync(vga_arb_device_init);
+
+static void vga_arb_firmware_fb_addr_tracker(struct pci_dev *pdev)
+{
+	resource_size_t fb_start;
+	resource_size_t fb_end;
+	unsigned int i;
+
+	if (!vga_arb_get_fb_range_from_screen_info(&fb_start, &fb_end))
+		return;
+
+	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
+		struct resource *ap = &pdev->resource[i];
+
+		if (resource_type(ap) != IORESOURCE_MEM)
+			continue;
+
+		if (!ap->start || !ap->end)
+			continue;
+
+		if (ap->start <= fb_start && fb_end <= ap->end) {
+			firmware_fb.pdev = pdev;
+			firmware_fb.bar = i;
+			firmware_fb.size = fb_end - fb_start + 1;
+			firmware_fb.offset = fb_start - ap->start;
+			firmware_fb.start = fb_start;
+			firmware_fb.end = fb_end;
+			break;
+		}
+	}
+}
+DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_ANY_ID, PCI_ANY_ID, PCI_CLASS_DISPLAY_VGA,
+			       8, vga_arb_firmware_fb_addr_tracker);
-- 
2.34.1