arch/x86/kernel/reboot_fixups_32.c

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