[PATCH] x86 reboot: Add reboot fixup for gx1/cs5530a

This patch by Jaya Kumar introduces a generic infrastructure to deal with
x86 chipsets with nonstandard reset sequences, and adds support for the
Geode gx1/cs5530a chipset.

Signed-off-by: Jaya Kumar <jayalk@intworks.biz>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index 17a0cbc..99b4f29 100644 (file)
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -653,6 +653,24 @@ config I8K
          Say Y if you intend to run this kernel on a Dell Inspiron 8000.
          Say N otherwise.
 
+config X86_REBOOTFIXUPS
+       bool "Enable X86 board specific fixups for reboot"
+       depends on X86
+       default n
+       ---help---
+         This enables chipset and/or board specific fixups to be done
+         in order to get reboot to work correctly. This is only needed on
+         some combinations of hardware and BIOS. The symptom, for which
+         this config is intended, is when reboot ends with a stalled/hung
+         system.
+
+         Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
+         combination.
+
+         Say Y if you want to enable the fixup. Currently, it's safe to
+         enable this option even if you don't need it.
+         Say N otherwise.
+
 config MICROCODE
        tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
        ---help---

diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile
index aacdae6..0fbcfe0 100644 (file)
--- a/arch/i386/kernel/Makefile
+++ b/arch/i386/kernel/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_X86_TRAMPOLINE)  += trampoline.o
 obj-$(CONFIG_X86_MPPARSE)      += mpparse.o
 obj-$(CONFIG_X86_LOCAL_APIC)   += apic.o nmi.o
 obj-$(CONFIG_X86_IO_APIC)      += io_apic.o
+obj-$(CONFIG_X86_REBOOTFIXUPS) += reboot_fixups.o
 obj-$(CONFIG_X86_NUMAQ)                += numaq.o
 obj-$(CONFIG_X86_SUMMIT_NUMA)  += summit.o
 obj-$(CONFIG_KPROBES)          += kprobes.o

diff --git a/arch/i386/kernel/reboot.c b/arch/i386/kernel/reboot.c
index 3d7e994..6dc27eb 100644 (file)
--- a/arch/i386/kernel/reboot.c
+++ b/arch/i386/kernel/reboot.c
@@ -13,6 +13,7 @@
 #include <asm/uaccess.h>
 #include <asm/apic.h>
 #include "mach_reboot.h"
+#include <linux/reboot_fixups.h>
 
 /*
  * Power off function, if any
@@ -348,6 +349,7 @@ void machine_restart(char * __unused)
                /* rebooting needs to touch the page at absolute addr 0 */
                *((unsigned short *)__va(0x472)) = reboot_mode;
                for (;;) {
+                       mach_reboot_fixups(); /* for board specific fixups */
                        mach_reboot();
                        /* That didn't work - force a triple fault.. */
                        __asm__ __volatile__("lidt %0": :"m" (no_idt));

diff --git a/arch/i386/kernel/reboot_fixups.c b/arch/i386/kernel/reboot_fixups.c
new file mode 100644 (file)
index 0000000..1b183b3
--- /dev/null
+++ b/arch/i386/kernel/reboot_fixups.c
@@ -0,0 +1,56 @@
+/*
+ * linux/arch/i386/kernel/reboot_fixups.c
+ *
+ * This is a good place to put board specific reboot fixups.
+ *
+ * List of supported fixups:
+ * geode-gx1/cs5530a - Jaya Kumar <jayalk@intworks.biz>
+ *
+ */
+
+#include <asm/delay.h>
+#include <linux/pci.h>
+
+static void cs5530a_warm_reset(struct pci_dev *dev)
+{
+       /* writing 1 to the reset control register, 0x44 causes the
+       cs5530a to perform a system warm reset */
+       pci_write_config_byte(dev, 0x44, 0x1);
+       udelay(50); /* shouldn't get here but be safe and spin-a-while */
+       return;
+}
+
+struct device_fixup {
+       unsigned int vendor;
+       unsigned int device;
+       void (*reboot_fixup)(struct pci_dev *);
+};
+
+static struct device_fixup fixups_table[] = {
+{ PCI_VENDOR_ID_CYRIX, PCI_DEVICE_ID_CYRIX_5530_LEGACY, cs5530a_warm_reset },
+};
+
+/*
+ * we see if any fixup is available for our current hardware. if there
+ * is a fixup, we call it and we expect to never return from it. if we
+ * do return, we keep looking and then eventually fall back to the
+ * standard mach_reboot on return.
+ */
+void mach_reboot_fixups(void)
+{
+       struct device_fixup *cur;
+       struct pci_dev *dev;
+       int i;
+
+       for (i=0; i < (sizeof(fixups_table)/sizeof(fixups_table[0])); i++) {
+               cur = &(fixups_table[i]);
+               dev = pci_get_device(cur->vendor, cur->device, 0);
+               if (!dev)
+                       continue;
+
+               cur->reboot_fixup(dev);
+       }
+
+       printk(KERN_WARNING "No reboot fixup found for your hardware\n");
+}
+

diff --git a/include/linux/reboot_fixups.h b/include/linux/reboot_fixups.h
new file mode 100644 (file)
index 0000000..480ea2d
--- /dev/null
+++ b/include/linux/reboot_fixups.h
@@ -0,0 +1,10 @@
+#ifndef _LINUX_REBOOT_FIXUPS_H
+#define _LINUX_REBOOT_FIXUPS_H
+
+#ifdef CONFIG_X86_REBOOTFIXUPS
+extern void mach_reboot_fixups(void);
+#else
+#define mach_reboot_fixups() ((void)(0))
+#endif
+
+#endif /* _LINUX_REBOOT_FIXUPS_H */