arch/x86/kernel/reboot_fixups_32.c

   1 /*
   2  * linux/arch/i386/kernel/reboot_fixups.c
   3  *
   4  * This is a good place to put board specific reboot fixups.
   5  *
   6  * List of supported fixups:
   7  * geode-gx1/cs5530a - Jaya Kumar <jayalk@intworks.biz>
   8  * geode-gx/lx/cs5536 - Andres Salomon <dilinger@debian.org>
   9  *
  10  */
  11
  12 #include <asm/delay.h>
  13 #include <linux/pci.h>
  14 #include <linux/interrupt.h>
  15 #include <asm/reboot_fixups.h>
  16 #include <asm/msr.h>
  17
  18 static void cs5530a_warm_reset(struct pci_dev *dev)
  19 {
  20         /* writing 1 to the reset control register, 0x44 causes the
  21         cs5530a to perform a system warm reset */
  22         pci_write_config_byte(dev, 0x44, 0x1);
  23         udelay(50); /* shouldn't get here but be safe and spin-a-while */
  24         return;
  25 }
  26
  27 static void cs5536_warm_reset(struct pci_dev *dev)
  28 {
  29         /*
  30          * 6.6.2.12 Soft Reset (DIVIL_SOFT_RESET)
  31          * writing 1 to the LSB of this MSR causes a hard reset.
  32          */
  33         wrmsrl(0x51400017, 1ULL);
  34         udelay(50); /* shouldn't get here but be safe and spin a while */
  35 }
  36
  37 struct device_fixup {
  38         unsigned int vendor;
  39         unsigned int device;
  40         void (*reboot_fixup)(struct pci_dev *);
  41 };
  42
  43 static struct device_fixup fixups_table[] = {
  44 { PCI_VENDOR_ID_CYRIX, PCI_DEVICE_ID_CYRIX_5530_LEGACY, cs5530a_warm_reset },
  45 { PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA, cs5536_warm_reset },
  46 };
  47
  48 /*
  49  * we see if any fixup is available for our current hardware. if there
  50  * is a fixup, we call it and we expect to never return from it. if we
  51  * do return, we keep looking and then eventually fall back to the
  52  * standard mach_reboot on return.
  53  */
  54 void mach_reboot_fixups(void)
  55 {
  56         struct device_fixup *cur;
  57         struct pci_dev *dev;
  58         int i;
  59
  60         /* we can be called from sysrq-B code. In such a case it is
  61          * prohibited to dig PCI */
  62         if (in_interrupt())
  63                 return;
  64
  65         for (i=0; i < ARRAY_SIZE(fixups_table); i++) {
  66                 cur = &(fixups_table[i]);
  67                 dev = pci_get_device(cur->vendor, cur->device, NULL);
  68                 if (!dev)
  69                         continue;
  70
  71                 cur->reboot_fixup(dev);
  72         }
  73 }
  74