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i.MX51: determine silicon revision dynamically 

Freescale redboot passes the silicon revision via
ATAG_REVISION. Remove this bootloader dependency by
doing the same as redboot does in the Kernel.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
Sascha Hauer 2010-03-19 10:50:55 +01:00
parent 3d1bc8626c
commit 5443856cad
2 changed files with 60 additions and 6 deletions
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53
arch/arm/mach-mx5/cpu.c
View File

@ -14,9 +14,62 @@
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <mach/hardware.h>
#include <asm/io.h>
static int cpu_silicon_rev = -1;
#define SI_REV 0x48
static void query_silicon_parameter(void)
{
void __iomem *rom = ioremap(MX51_IROM_BASE_ADDR, MX51_IROM_SIZE);
u32 rev;
if (!rom) {
cpu_silicon_rev = -EINVAL;
return;
}
rev = readl(rom + SI_REV);
switch (rev) {
case 0x1:
cpu_silicon_rev = MX51_CHIP_REV_1_0;
break;
case 0x2:
cpu_silicon_rev = MX51_CHIP_REV_1_1;
break;
case 0x10:
cpu_silicon_rev = MX51_CHIP_REV_2_0;
break;
case 0x20:
cpu_silicon_rev = MX51_CHIP_REV_3_0;
break;
default:
cpu_silicon_rev = 0;
}
iounmap(rom);
}
/*
* Returns:
* the silicon revision of the cpu
* -EINVAL - not a mx51
*/
int mx51_revision(void)
{
if (!cpu_is_mx51())
return -EINVAL;
if (cpu_silicon_rev == -1)
query_silicon_parameter();
return cpu_silicon_rev;
}
EXPORT_SYMBOL(mx51_revision);
static int __init post_cpu_init(void)
{
unsigned int reg;

13
arch/arm/plat-mxc/include/mach/mx51.h
View File

@ -27,6 +27,12 @@
*
*/
/*
* IROM
*/
#define MX51_IROM_BASE_ADDR 0x0
#define MX51_IROM_SIZE SZ_64K
/*
* IRAM
*/
@ -438,12 +444,7 @@
#if !defined(__ASSEMBLY__) && !defined(__MXC_BOOT_UNCOMPRESS)
extern unsigned int system_rev;
static inline unsigned int mx51_revision(void)
{
return system_rev;
}
extern int mx51_revision(void);
#endif
#endif /* __ASM_ARCH_MXC_MX51_H__ */