[MTD] Remove PCI dependency for Geode CS553[56] NAND controller.

PCI is faked on these devices by SMM traps. Don't depend on that --
check for the chipset directly instead.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

1 files changed, 30 insertions, 3 deletions

diff --git a/drivers/mtd/nand/cs553x_nand.c b/drivers/mtd/nand/cs553x_nand.c
index 1e0348ae325f..e0a1d386e581 100644
--- a/drivers/mtd/nand/cs553x_nand.c
+++ b/drivers/mtd/nand/cs553x_nand.c
@@ -31,6 +31,10 @@
 
 #define NR_CS553X_CONTROLLERS   4
 
+#define MSR_DIVIL_GLD_CAP       0x51400000      /* DIVIL capabilitiies */
+#define CAP_CS5535              0x2df000ULL
+#define CAP_CS5536              0x5df500ULL
+
 /* NAND Timing MSRs */
 #define MSR_NANDF_DATA          0x5140001b      /* NAND Flash Data Timing MSR */
 #define MSR_NANDF_CTL           0x5140001c      /* NAND Flash Control Timing */
@@ -252,17 +256,40 @@ out:
         return err;
 }
 
+static int is_geode(void)
+{
+        /* These are the CPUs which will have a CS553[56] companion chip */
+        if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
+            boot_cpu_data.x86 == 5 &&
+            boot_cpu_data.x86_model == 10)
+                return 1; /* Geode LX */
+
+        if ((boot_cpu_data.x86_vendor == X86_VENDOR_NSC ||
+             boot_cpu_data.x86_vendor == X86_VENDOR_CYRIX) &&
+            boot_cpu_data.x86 == 5 &&
+            boot_cpu_data.x86_model == 5)
+                return 1; /* Geode GX (née GX2) */
+
+        return 0;
+}
+
 static int __init cs553x_init(void)
 {
         int err = -ENXIO;
         int i;
         uint64_t val;
 
-        /* Check whether we actually have a CS5535 or CS5536 */
-        if (!pci_find_device(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA, NULL) &&
-            !pci_find_device(PCI_VENDOR_ID_NS,  PCI_DEVICE_ID_NS_CS5535_ISA, NULL))
+        /* If the CPU isn't a Geode GX or LX, abort */
+        if (!is_geode())
+                return -ENXIO;
+
+        /* If it doesn't have the CS553[56], abort */
+        rdmsrl(MSR_DIVIL_GLD_CAP, val);
+        val &= ~0xFFULL;
+        if (val != CAP_CS5535 && val != CAP_CS5536)
                 return -ENXIO;
 
+        /* If it doesn't have the NAND controller enabled, abort */
         rdmsrl(MSR_DIVIL_BALL_OPTS, val);
         if (val & 1) {
                 printk(KERN_INFO "CS553x NAND controller: Flash I/O not enabled in MSR_DIVIL_BALL_OPTS.\n");