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>

1 files changed, 38 insertions, 70 deletions

diff --git a/arch/x86/pci/pcbios.c b/arch/x86/pci/pcbios.c
index 9b83b9051ae7..9770e55e768f 100644
--- 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);