diff options
| -rw-r--r-- | arch/mips/generic/board-ingenic.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/arch/mips/generic/board-ingenic.c b/arch/mips/generic/board-ingenic.c index 7a4fce06875d..1f4906875e7b 100644 --- a/arch/mips/generic/board-ingenic.c +++ b/arch/mips/generic/board-ingenic.c @@ -17,6 +17,7 @@ #include <linux/types.h> #include <asm/bootinfo.h> +#include <asm/io.h> #include <asm/machine.h> #include <asm/reboot.h> @@ -60,6 +61,50 @@ static __init char *ingenic_get_system_type(unsigned long machtype) } } +#define INGENIC_CGU_BASE 0x10000000 +#define JZ4750_CGU_CPCCR_ECS BIT(30) +#define JZ4760_CGU_CPCCR_ECS BIT(31) + +static __init void ingenic_force_12M_ext(const void *fdt, unsigned int mask) +{ + const __be32 *prop; + unsigned int cpccr; + void __iomem *cgu; + bool use_div; + int offset; + + offset = fdt_path_offset(fdt, "/ext"); + if (offset < 0) + return; + + prop = fdt_getprop(fdt, offset, "clock-frequency", NULL); + if (!prop) + return; + + /* + * If the external oscillator is 24 MHz, enable the /2 divider to + * drive it down to 12 MHz, since this is what the hardware can work + * with. + * The 16 MHz cutoff value is arbitrary; setting it to 12 MHz would not + * work as the crystal frequency (as reported in the Device Tree) might + * be slightly above this value. + */ + use_div = be32_to_cpup(prop) >= 16000000; + + cgu = ioremap(INGENIC_CGU_BASE, 0x4); + if (!cgu) + return; + + cpccr = ioread32(cgu); + if (use_div) + cpccr |= mask; + else + cpccr &= ~mask; + iowrite32(cpccr, cgu); + + iounmap(cgu); +} + static __init const void *ingenic_fixup_fdt(const void *fdt, const void *match_data) { /* @@ -73,6 +118,18 @@ static __init const void *ingenic_fixup_fdt(const void *fdt, const void *match_d mips_machtype = (unsigned long)match_data; system_type = ingenic_get_system_type(mips_machtype); + switch (mips_machtype) { + case MACH_INGENIC_JZ4750: + case MACH_INGENIC_JZ4755: + ingenic_force_12M_ext(fdt, JZ4750_CGU_CPCCR_ECS); + break; + case MACH_INGENIC_JZ4760: + ingenic_force_12M_ext(fdt, JZ4760_CGU_CPCCR_ECS); + break; + default: + break; + } + return fdt; } |