x86/PCI: Simplify pci_bios_{read,write}

There is some repetitive code in the switch/case statements in
pci_bios_read() and pci_bios_write().  Factor out the BIOS function
IDs and the result widths to simplify the code.

Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/pci/pcbios.c b/arch/x86/pci/pcbios.c
index 9b83b90..9770e55 100644 (file)
--- a/arch/x86/pci/pcbios.c
+++ b/arch/x86/pci/pcbios.c
@@ -180,6 +180,7 @@ static int pci_bios_read(unsigned int seg, unsigned int bus,
        unsigned long result = 0;
        unsigned long flags;
        unsigned long bx = (bus << 8) | devfn;
+       u16 number = 0, mask = 0;
 
        WARN_ON(seg);
        if (!value || (bus > 255) || (devfn > 255) || (reg > 255))
@@ -189,53 +190,35 @@ static int pci_bios_read(unsigned int seg, unsigned int bus,
 
        switch (len) {
        case 1:
-               __asm__("lcall *(%%esi); cld\n\t"
-                       "jc 1f\n\t"
-                       "xor %%ah, %%ah\n"
-                       "1:"
-                       : "=c" (*value),
-                         "=a" (result)
-                       : "1" (PCIBIOS_READ_CONFIG_BYTE),
-                         "b" (bx),
-                         "D" ((long)reg),
-                         "S" (&pci_indirect));
-               /*
-                * Zero-extend the result beyond 8 bits, do not trust the
-                * BIOS having done it:
-                */
-               *value &= 0xff;
+               number = PCIBIOS_READ_CONFIG_BYTE;
+               mask = 0xff;
                break;
        case 2:
-               __asm__("lcall *(%%esi); cld\n\t"
-                       "jc 1f\n\t"
-                       "xor %%ah, %%ah\n"
-                       "1:"
-                       : "=c" (*value),
-                         "=a" (result)
-                       : "1" (PCIBIOS_READ_CONFIG_WORD),
-                         "b" (bx),
-                         "D" ((long)reg),
-                         "S" (&pci_indirect));
-               /*
-                * Zero-extend the result beyond 16 bits, do not trust the
-                * BIOS having done it:
-                */
-               *value &= 0xffff;
+               number = PCIBIOS_READ_CONFIG_WORD;
+               mask = 0xffff;
                break;
        case 4:
-               __asm__("lcall *(%%esi); cld\n\t"
-                       "jc 1f\n\t"
-                       "xor %%ah, %%ah\n"
-                       "1:"
-                       : "=c" (*value),
-                         "=a" (result)
-                       : "1" (PCIBIOS_READ_CONFIG_DWORD),
-                         "b" (bx),
-                         "D" ((long)reg),
-                         "S" (&pci_indirect));
+               number = PCIBIOS_READ_CONFIG_DWORD;
                break;
        }
 
+       __asm__("lcall *(%%esi); cld\n\t"
+               "jc 1f\n\t"
+               "xor %%ah, %%ah\n"
+               "1:"
+               : "=c" (*value),
+                 "=a" (result)
+               : "1" (number),
+                 "b" (bx),
+                 "D" ((long)reg),
+                 "S" (&pci_indirect));
+       /*
+        * Zero-extend the result beyond 8 or 16 bits, do not trust the
+        * BIOS having done it:
+        */
+       if (mask)
+               *value &= mask;
+
        raw_spin_unlock_irqrestore(&pci_config_lock, flags);
 
        return (int)((result & 0xff00) >> 8);
@@ -247,6 +230,7 @@ static int pci_bios_write(unsigned int seg, unsigned int bus,
        unsigned long result = 0;
        unsigned long flags;
        unsigned long bx = (bus << 8) | devfn;
+       u16 number = 0;
 
        WARN_ON(seg);
        if ((bus > 255) || (devfn > 255) || (reg > 255)) 
@@ -256,43 +240,27 @@ static int pci_bios_write(unsigned int seg, unsigned int bus,
 
        switch (len) {
        case 1:
-               __asm__("lcall *(%%esi); cld\n\t"
-                       "jc 1f\n\t"
-                       "xor %%ah, %%ah\n"
-                       "1:"
-                       : "=a" (result)
-                       : "0" (PCIBIOS_WRITE_CONFIG_BYTE),
-                         "c" (value),
-                         "b" (bx),
-                         "D" ((long)reg),
-                         "S" (&pci_indirect));
+               number = PCIBIOS_WRITE_CONFIG_BYTE;
                break;
        case 2:
-               __asm__("lcall *(%%esi); cld\n\t"
-                       "jc 1f\n\t"
-                       "xor %%ah, %%ah\n"
-                       "1:"
-                       : "=a" (result)
-                       : "0" (PCIBIOS_WRITE_CONFIG_WORD),
-                         "c" (value),
-                         "b" (bx),
-                         "D" ((long)reg),
-                         "S" (&pci_indirect));
+               number = PCIBIOS_WRITE_CONFIG_WORD;
                break;
        case 4:
-               __asm__("lcall *(%%esi); cld\n\t"
-                       "jc 1f\n\t"
-                       "xor %%ah, %%ah\n"
-                       "1:"
-                       : "=a" (result)
-                       : "0" (PCIBIOS_WRITE_CONFIG_DWORD),
-                         "c" (value),
-                         "b" (bx),
-                         "D" ((long)reg),
-                         "S" (&pci_indirect));
+               number = PCIBIOS_WRITE_CONFIG_DWORD;
                break;
        }
 
+       __asm__("lcall *(%%esi); cld\n\t"
+               "jc 1f\n\t"
+               "xor %%ah, %%ah\n"
+               "1:"
+               : "=a" (result)
+               : "0" (number),
+                 "c" (value),
+                 "b" (bx),
+                 "D" ((long)reg),
+                 "S" (&pci_indirect));
+
        raw_spin_unlock_irqrestore(&pci_config_lock, flags);
 
        return (int)((result & 0xff00) >> 8);