[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>

1 files changed, 56 insertions, 0 deletions

diff --git a/arch/i386/kernel/reboot_fixups.c b/arch/i386/kernel/reboot_fixups.c
new file mode 100644
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");
+}
+