diff options
Diffstat (limited to 'arch/mips/lantiq/clk.c')
| -rw-r--r-- | arch/mips/lantiq/clk.c | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/arch/mips/lantiq/clk.c b/arch/mips/lantiq/clk.c new file mode 100644 index 0000000..9456089 --- /dev/null +++ b/arch/mips/lantiq/clk.c @@ -0,0 +1,140 @@ +/* + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published + * by the Free Software Foundation. + * + * Copyright (C) 2010 Thomas Langer <thomas.langer@lantiq.com> + * Copyright (C) 2010 John Crispin <blogic@openwrt.org> + */ +#include <linux/io.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/list.h> + +#include <asm/time.h> +#include <asm/irq.h> +#include <asm/div64.h> + +#include <lantiq_soc.h> + +#include "clk.h" + +struct clk { + const char *name; + unsigned long rate; + unsigned long (*get_rate) (void); +}; + +static struct clk *cpu_clk; +static int cpu_clk_cnt; + +/* lantiq socs have 3 static clocks */ +static struct clk cpu_clk_generic[] = { + { + .name = "cpu", + .get_rate = ltq_get_cpu_hz, + }, { + .name = "fpi", + .get_rate = ltq_get_fpi_hz, + }, { + .name = "io", + .get_rate = ltq_get_io_region_clock, + }, +}; + +static struct resource ltq_cgu_resource = { + .name = "cgu", + .start = LTQ_CGU_BASE_ADDR, + .end = LTQ_CGU_BASE_ADDR + LTQ_CGU_SIZE - 1, + .flags = IORESOURCE_MEM, +}; + +/* remapped clock register range */ +void __iomem *ltq_cgu_membase; + +void clk_init(void) +{ + cpu_clk = cpu_clk_generic; + cpu_clk_cnt = ARRAY_SIZE(cpu_clk_generic); +} + +static inline int clk_good(struct clk *clk) +{ + return clk && !IS_ERR(clk); +} + +unsigned long clk_get_rate(struct clk *clk) +{ + if (unlikely(!clk_good(clk))) + return 0; + + if (clk->rate != 0) + return clk->rate; + + if (clk->get_rate != NULL) + return clk->get_rate(); + + return 0; +} +EXPORT_SYMBOL(clk_get_rate); + +struct clk *clk_get(struct device *dev, const char *id) +{ + int i; + + for (i = 0; i < cpu_clk_cnt; i++) + if (!strcmp(id, cpu_clk[i].name)) + return &cpu_clk[i]; + BUG(); + return ERR_PTR(-ENOENT); +} +EXPORT_SYMBOL(clk_get); + +void clk_put(struct clk *clk) +{ + /* not used */ +} +EXPORT_SYMBOL(clk_put); + +static inline u32 ltq_get_counter_resolution(void) +{ + u32 res; + + __asm__ __volatile__( + ".set push\n" + ".set mips32r2\n" + "rdhwr %0, $3\n" + ".set pop\n" + : "=&r" (res) + : /* no input */ + : "memory"); + + return res; +} + +void __init plat_time_init(void) +{ + struct clk *clk; + + if (insert_resource(&iomem_resource, <q_cgu_resource) < 0) + panic("Failed to insert cgu memory\n"); + + if (request_mem_region(ltq_cgu_resource.start, + resource_size(<q_cgu_resource), "cgu") < 0) + panic("Failed to request cgu memory\n"); + + ltq_cgu_membase = ioremap_nocache(ltq_cgu_resource.start, + resource_size(<q_cgu_resource)); + if (!ltq_cgu_membase) { + pr_err("Failed to remap cgu memory\n"); + unreachable(); + } + clk = clk_get(0, "cpu"); + mips_hpt_frequency = clk_get_rate(clk) / ltq_get_counter_resolution(); + write_c0_compare(read_c0_count()); + clk_put(clk); +} |