MIPS: pci-legacy: revert "use generic pci_enable_resources"

This mostly reverts commit 99bca61 ("MIPS: pci-legacy: use generic
pci_enable_resources"). Fixes regressions such as:
  ata_piix 0000:00:0a.1: can't enable device: BAR 0 [io  0x01f0-0x01f7] not
	claimed
  ata_piix: probe of 0000:00:0a.1 failed with error -22

The only changes from the strict revert are to fix checkpatch errors:
  ERROR: spaces required around that '=' (ctx:VxV)
  #33: FILE: arch/mips/pci/pci-legacy.c:252:
  +	for (idx=0; idx < PCI_NUM_RESOURCES; idx++) {
 	        ^

  ERROR: do not use assignment in if condition
  #67: FILE: arch/mips/pci/pci-legacy.c:284:
  +	if ((err = pcibios_enable_resources(dev, mask)) < 0)

Reported-by: Guenter Roeck <[email protected]>
Signed-off-by: Ilya Lipnitskiy <[email protected]>
Tested-by: Guenter Roeck <[email protected]>
Signed-off-by: Thomas Bogendoerfer <[email protected]>

Author: lipnitsk

arch/mips/pci/pci-legacy.c

@@ -241,9 +241,45 @@ static int __init pcibios_init(void)
 
 subsys_initcall(pcibios_init);
 
+static int pcibios_enable_resources(struct pci_dev *dev, int mask)
+{
+	u16 cmd, old_cmd;
+	int idx;
+	struct resource *r;
+
+	pci_read_config_word(dev, PCI_COMMAND, &cmd);
+	old_cmd = cmd;
+	for (idx = 0; idx < PCI_NUM_RESOURCES; idx++) {
+		/* Only set up the requested stuff */
+		if (!(mask & (1<<idx)))
+			continue;
+
+		r = &dev->resource[idx];
+		if (!(r->flags & (IORESOURCE_IO | IORESOURCE_MEM)))
+			continue;
+		if ((idx == PCI_ROM_RESOURCE) &&
+				(!(r->flags & IORESOURCE_ROM_ENABLE)))
+			continue;
+		if (!r->start && r->end) {
+			pci_err(dev,
+				"can't enable device: resource collisions\n");
+			return -EINVAL;
+		}
+		if (r->flags & IORESOURCE_IO)
+			cmd |= PCI_COMMAND_IO;
+		if (r->flags & IORESOURCE_MEM)
+			cmd |= PCI_COMMAND_MEMORY;
+	}
+	if (cmd != old_cmd) {
+		pci_info(dev, "enabling device (%04x -> %04x)\n", old_cmd, cmd);
+		pci_write_config_word(dev, PCI_COMMAND, cmd);
+	}
+	return 0;
+}
+
 int pcibios_enable_device(struct pci_dev *dev, int mask)
 {
-	int err = pci_enable_resources(dev, mask);
+	int err = pcibios_enable_resources(dev, mask);
 
 	if (err < 0)
 		return err;