[PATCH] MIPS: pci-legacy: revert "use generic pci_enable_resources"

[Ilya Lipnitskiy]

This mostly reverts commit 99bca615d895 ("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 <li...@roeck-us.net>
Signed-off-by: Ilya Lipnitskiy <ilya.lipnits...@gmail.com>
---
Guenter, sorry about this - let's just revert this for now to minimize
turmoil to the legacy PCI code. Obviously, this needs more testing
before applying. Thanks for your report!

 arch/mips/pci/pci-legacy.c | 38 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/arch/mips/pci/pci-legacy.c b/arch/mips/pci/pci-legacy.c
index c24226ea0a6e..468722c8a5c6 100644
--- a/arch/mips/pci/pci-legacy.c
+++ b/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;
-- 
2.31.1