MIPS: ath79: fix broken ar724x_pci_{read,write} functions

The current ar724x_pci_{read,write} functions are
broken. Due to that, pci_read_config_byte returns
with bogus values, and pci_write_config_{byte,word}
unconditionally clears the accessed PCI configuration
registers instead of changing the value of them.

The patch fixes the broken functions, thus the PCI
configuration space can be accessed correctly.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3493/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/pci/pci-ar724x.c b/arch/mips/pci/pci-ar724x.c
index 342bf4ab8960131596ccb13b46d30be003d02b3d..bb4f2162d4e4b3464c2c0c2856725e30356c0f57 100644 (file)
--- a/arch/mips/pci/pci-ar724x.c
+++ b/arch/mips/pci/pci-ar724x.c
@@ -22,8 +22,9 @@ static void __iomem *ar724x_pci_devcfg_base;
 static int ar724x_pci_read(struct pci_bus *bus, unsigned int devfn, int where,
                            int size, uint32_t *value)
 {
-       unsigned long flags, addr, tval, mask;
+       unsigned long flags;
        void __iomem *base;
+       u32 data;
 
        if (devfn)
                return PCIBIOS_DEVICE_NOT_FOUND;
@@ -31,24 +32,22 @@ static int ar724x_pci_read(struct pci_bus *bus, unsigned int devfn, int where,
        base = ar724x_pci_devcfg_base;
 
        spin_lock_irqsave(&ar724x_pci_lock, flags);
+       data = __raw_readl(base + (where & ~3));
 
        switch (size) {
        case 1:
-               addr = where & ~3;
-               mask = 0xff000000 >> ((where % 4) * 8);
-               tval = __raw_readl(base + addr);
-               tval = tval & ~mask;
-               *value = (tval >> ((4 - (where % 4))*8));
+               if (where & 1)
+                       data >>= 8;
+               if (where & 2)
+                       data >>= 16;
+               data &= 0xff;
                break;
        case 2:
-               addr = where & ~3;
-               mask = 0xffff0000 >> ((where % 4)*8);
-               tval = __raw_readl(base + addr);
-               tval = tval & ~mask;
-               *value = (tval >> ((4 - (where % 4))*8));
+               if (where & 2)
+                       data >>= 16;
+               data &= 0xffff;
                break;
        case 4:
-               *value = __raw_readl(base + where);
                break;
        default:
                spin_unlock_irqrestore(&ar724x_pci_lock, flags);
@@ -57,6 +56,7 @@ static int ar724x_pci_read(struct pci_bus *bus, unsigned int devfn, int where,
        }
 
        spin_unlock_irqrestore(&ar724x_pci_lock, flags);
+       *value = data;
 
        return PCIBIOS_SUCCESSFUL;
 }
@@ -64,8 +64,10 @@ static int ar724x_pci_read(struct pci_bus *bus, unsigned int devfn, int where,
 static int ar724x_pci_write(struct pci_bus *bus, unsigned int devfn, int where,
                             int size, uint32_t value)
 {
-       unsigned long flags, tval, addr, mask;
+       unsigned long flags;
        void __iomem *base;
+       u32 data;
+       int s;
 
        if (devfn)
                return PCIBIOS_DEVICE_NOT_FOUND;
@@ -73,26 +75,21 @@ static int ar724x_pci_write(struct pci_bus *bus, unsigned int devfn, int where,
        base = ar724x_pci_devcfg_base;
 
        spin_lock_irqsave(&ar724x_pci_lock, flags);
+       data = __raw_readl(base + (where & ~3));
 
        switch (size) {
        case 1:
-               addr = where & ~3;
-               mask = 0xff000000 >> ((where % 4)*8);
-               tval = __raw_readl(base + addr);
-               tval = tval & ~mask;
-               tval |= (value << ((4 - (where % 4))*8)) & mask;
-               __raw_writel(tval, base + addr);
+               s = ((where & 3) * 8);
+               data &= ~(0xff << s);
+               data |= ((value & 0xff) << s);
                break;
        case 2:
-               addr = where & ~3;
-               mask = 0xffff0000 >> ((where % 4)*8);
-               tval = __raw_readl(base + addr);
-               tval = tval & ~mask;
-               tval |= (value << ((4 - (where % 4))*8)) & mask;
-               __raw_writel(tval, base + addr);
+               s = ((where & 2) * 8);
+               data &= ~(0xffff << s);
+               data |= ((value & 0xffff) << s);
                break;
        case 4:
-               __raw_writel(value, (base + where));
+               data = value;
                break;
        default:
                spin_unlock_irqrestore(&ar724x_pci_lock, flags);
@@ -100,6 +97,9 @@ static int ar724x_pci_write(struct pci_bus *bus, unsigned int devfn, int where,
                return PCIBIOS_BAD_REGISTER_NUMBER;
        }
 
+       __raw_writel(data, base + (where & ~3));
+       /* flush write */
+       __raw_readl(base + (where & ~3));
        spin_unlock_irqrestore(&ar724x_pci_lock, flags);
 
        return PCIBIOS_SUCCESSFUL;