x86: Set up a shared syscon numbering schema

Each system controller can have a number to identify it. It can then be
accessed using syscon_get_by_driver_data(). Put this in a shared header
file and update the only current user.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

arch/x86/cpu/ivybridge/early_me.c

@@ -10,6 +10,7 @@
 #include <dm.h>
 #include <errno.h>
 #include <asm/pci.h>
+#include <asm/cpu.h>
 #include <asm/processor.h>
 #include <asm/arch/me.h>
 #include <asm/arch/pch.h>
@@ -189,7 +190,7 @@ int intel_early_me_init_done(struct udevice *dev, struct udevice *me_dev,
 }
 
 static const struct udevice_id ivybridge_syscon_ids[] = {
-	{ .compatible = "intel,me", },
+	{ .compatible = "intel,me", .data = X86_SYSCON_ME },
 	{ }
 };
 

arch/x86/cpu/ivybridge/sdram.c

@@ -18,6 +18,8 @@
 #include <rtc.h>
 #include <spi.h>
 #include <spi_flash.h>
+#include <syscon.h>
+#include <asm/cpu.h>
 #include <asm/processor.h>
 #include <asm/gpio.h>
 #include <asm/global_data.h>
@@ -739,11 +741,9 @@ int dram_init(void)
 		return ret;
 	if (!dev)
 		return -ENODEV;
-	ret = uclass_first_device(UCLASS_SYSCON, &me_dev);
+	ret = syscon_get_by_driver_data(X86_SYSCON_ME, &me_dev);
 	if (ret)
 		return ret;
-	if (!me_dev)
-		return -ENODEV;
 	debug("Boot mode %d\n", gd->arch.pei_boot_mode);
 	debug("mrc_input %p\n", pei_data.mrc_input);
 	pei_data.boot_mode = gd->arch.pei_boot_mode;

arch/x86/include/asm/cpu.h

@@ -45,6 +45,15 @@ enum {
 	GDT_BASE_HIGH_MASK	= 0xf,
 };
 
+/*
+ * System controllers in an x86 system. We mostly need to just find these and
+ * use them on PCI. At some point these might have their own uclass.
+ */
+enum {
+	X86_NONE,
+	X86_SYSCON_ME,		/* Intel Management Engine */
+};
+
 struct cpuid_result {
 	uint32_t eax;
 	uint32_t ebx;

configs/chromebox_panther_defconfig

@@ -16,6 +16,8 @@ CONFIG_CMD_BOOTSTAGE=y
 CONFIG_CMD_TPM=y
 CONFIG_CMD_TPM_TEST=y
 CONFIG_OF_CONTROL=y
+CONFIG_REGMAP=y
+CONFIG_SYSCON=y
 CONFIG_CMD_CROS_EC=y
 CONFIG_CROS_EC=y
 CONFIG_CROS_EC_LPC=y