pci: Update pci_set_vga_state() to call arch functions

Update pci_set_vga_state to call arch dependent functions to enable Legacy
VGA I/O transactions to be redirected to correct target.

[akpm@linux-foundation.org: make pci_register_set_vga_state() __init]
Signed-off-by: Mike Travis <travis@sgi.com>
LKML-Reference: <201002022238.o12McE1J018723@imap1.linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Robin Holt <holt@sgi.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: David Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

drivers/pci/pci.c

@@ -2615,6 +2615,23 @@ int pci_resource_bar(struct pci_dev *dev, int resno, enum pci_bar_type *type)
 	return 0;
 }
 
+/* Some architectures require additional programming to enable VGA */
+static arch_set_vga_state_t arch_set_vga_state;
+
+void __init pci_register_set_vga_state(arch_set_vga_state_t func)
+{
+	arch_set_vga_state = func;	/* NULL disables */
+}
+
+static int pci_set_vga_state_arch(struct pci_dev *dev, bool decode,
+		      unsigned int command_bits, bool change_bridge)
+{
+	if (arch_set_vga_state)
+		return arch_set_vga_state(dev, decode, command_bits,
+						change_bridge);
+	return 0;
+}
+
 /**
  * pci_set_vga_state - set VGA decode state on device and parents if requested
  * @dev: the PCI device
@@ -2628,9 +2645,15 @@ int pci_set_vga_state(struct pci_dev *dev, bool decode,
 	struct pci_bus *bus;
 	struct pci_dev *bridge;
 	u16 cmd;
+	int rc;
 
 	WARN_ON(command_bits & ~(PCI_COMMAND_IO|PCI_COMMAND_MEMORY));
 
+	/* ARCH specific VGA enables */
+	rc = pci_set_vga_state_arch(dev, decode, command_bits, change_bridge);
+	if (rc)
+		return rc;
+
 	pci_read_config_word(dev, PCI_COMMAND, &cmd);
 	if (decode == true)
 		cmd |= command_bits;
@@ -2845,6 +2868,7 @@ EXPORT_SYMBOL(pcim_pin_device);
 EXPORT_SYMBOL(pci_disable_device);
 EXPORT_SYMBOL(pci_find_capability);
 EXPORT_SYMBOL(pci_bus_find_capability);
+EXPORT_SYMBOL(pci_register_set_vga_state);
 EXPORT_SYMBOL(pci_release_regions);
 EXPORT_SYMBOL(pci_request_regions);
 EXPORT_SYMBOL(pci_request_regions_exclusive);
@@ -2877,4 +2901,3 @@ EXPORT_SYMBOL(pci_target_state);
 EXPORT_SYMBOL(pci_prepare_to_sleep);
 EXPORT_SYMBOL(pci_back_from_sleep);
 EXPORT_SYMBOL_GPL(pci_set_pcie_reset_state);
-

include/linux/pci.h

@@ -955,6 +955,11 @@ static inline int pci_proc_domain(struct pci_bus *bus)
 }
 #endif /* CONFIG_PCI_DOMAINS */
 
+/* some architectures require additional setup to direct VGA traffic */
+typedef int (*arch_set_vga_state_t)(struct pci_dev *pdev, bool decode,
+		      unsigned int command_bits, bool change_bridge);
+extern void pci_register_set_vga_state(arch_set_vga_state_t func);
+
 #else /* CONFIG_PCI is not enabled */
 
 /*