diff options
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/mach-shmobile/setup-r8a7790.c | 51 |
1 files changed, 45 insertions, 6 deletions
diff --git a/arch/arm/mach-shmobile/setup-r8a7790.c b/arch/arm/mach-shmobile/setup-r8a7790.c index 6acddc139d88..4c96dad21195 100644 --- a/arch/arm/mach-shmobile/setup-r8a7790.c +++ b/arch/arm/mach-shmobile/setup-r8a7790.c @@ -210,14 +210,53 @@ u32 __init r8a7790_read_mode_pins(void) return mode; } +#define CNTCR 0 +#define CNTFID0 0x20 + void __init r8a7790_timer_init(void) { - void __iomem *cntcr; - - /* make sure arch timer is started by setting bit 0 of CNTCT */ - cntcr = ioremap(0xe6080000, PAGE_SIZE); - iowrite32(1, cntcr); - iounmap(cntcr); +#ifdef CONFIG_ARM_ARCH_TIMER + u32 mode = r8a7790_read_mode_pins(); + void __iomem *base; + int extal_mhz = 0; + u32 freq; + + /* At Linux boot time the r8a7790 arch timer comes up + * with the counter disabled. Moreover, it may also report + * a potentially incorrect fixed 13 MHz frequency. To be + * correct these registers need to be updated to use the + * frequency EXTAL / 2 which can be determined by the MD pins. + */ + + switch (mode & (MD(14) | MD(13))) { + case 0: + extal_mhz = 15; + break; + case MD(13): + extal_mhz = 20; + break; + case MD(14): + extal_mhz = 26; + break; + case MD(13) | MD(14): + extal_mhz = 30; + break; + } + + /* The arch timer frequency equals EXTAL / 2 */ + freq = extal_mhz * (1000000 / 2); + + /* Remap "armgcnt address map" space */ + base = ioremap(0xe6080000, PAGE_SIZE); + + /* Update registers with correct frequency */ + iowrite32(freq, base + CNTFID0); + asm volatile("mcr p15, 0, %0, c14, c0, 0" : : "r" (freq)); + + /* make sure arch timer is started by setting bit 0 of CNTCR */ + iowrite32(1, base + CNTCR); + iounmap(base); +#endif /* CONFIG_ARM_ARCH_TIMER */ shmobile_timer_init(); } |