davinci: Support JTAG ID register at any address

The Davinci cpu_is_davinci_*() macros use the SoC part number
and variant retrieved from the JTAG ID register to determine the
type of cpu that the kernel is running on.  Currently, the code to
read the JTAG ID register assumes that the register is always at
the same base address.  This isn't true on some newer SoCs.

To solve this, have the SoC-specific code set the JTAG ID register
base address in soc_info structure and add a 'cpu_id' member to it.
'cpu_id' will be used by the cpu_is_davinci_*() macros to match
the cpu id.  Also move the info used to identify the cpu type into
the SoC-specific code to keep all SoC-specific code together.

The common code will read the JTAG ID register, search through
an array of davinci_id structures to identify the cpu type.
Once identified, it will set the 'cpu_id' member of the soc_info
structure to the proper value and the cpu_is_davinci_*() macros
will now work.

Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

1 files changed, 28 insertions, 1 deletions

diff --git a/arch/arm/mach-davinci/common.c b/arch/arm/mach-davinci/common.c
index 9a5486f5519c..29b3a8d51211 100644
--- a/arch/arm/mach-davinci/common.c
+++ b/arch/arm/mach-davinci/common.c
@@ -15,13 +15,31 @@
 #include <asm/mach/map.h>
 
 #include <mach/common.h>
+#include <mach/cputype.h>
 
 struct davinci_soc_info davinci_soc_info;
 EXPORT_SYMBOL(davinci_soc_info);
 
+static struct davinci_id * __init davinci_get_id(u32 jtag_id)
+{
+	int i;
+	struct davinci_id *dip;
+	u8 variant = (jtag_id & 0xf0000000) >> 28;
+	u16 part_no = (jtag_id & 0x0ffff000) >> 12;
+
+	for (i = 0, dip = davinci_soc_info.ids; i < davinci_soc_info.ids_num;
+			i++, dip++)
+		/* Don't care about the manufacturer right now */
+		if ((dip->part_no == part_no) && (dip->variant == variant))
+			return dip;
+
+	return NULL;
+}
+
 void __init davinci_common_init(struct davinci_soc_info *soc_info)
 {
 	int ret;
+	struct davinci_id *dip;
 
 	if (!soc_info) {
 		ret = -EINVAL;
@@ -46,7 +64,16 @@ void __init davinci_common_init(struct davinci_soc_info *soc_info)
 	 * We want to check CPU revision early for cpu_is_xxxx() macros.
 	 * IO space mapping must be initialized before we can do that.
 	 */
-	davinci_check_revision();
+	davinci_soc_info.jtag_id = __raw_readl(davinci_soc_info.jtag_id_base);
+
+	dip = davinci_get_id(davinci_soc_info.jtag_id);
+	if (!dip) {
+		ret = -EINVAL;
+		goto err;
+	}
+
+	davinci_soc_info.cpu_id = dip->cpu_id;
+	pr_info("DaVinci %s variant 0x%x\n", dip->name, dip->variant);
 
 	return;