diff options
Diffstat (limited to 'arch/sh/kernel/cpu/sh4/clock-sh4-202.c')
| -rw-r--r-- | arch/sh/kernel/cpu/sh4/clock-sh4-202.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/arch/sh/kernel/cpu/sh4/clock-sh4-202.c b/arch/sh/kernel/cpu/sh4/clock-sh4-202.c new file mode 100644 index 000000000..4b5bab5f8 --- /dev/null +++ b/arch/sh/kernel/cpu/sh4/clock-sh4-202.c @@ -0,0 +1,177 @@ +/* + * arch/sh/kernel/cpu/sh4/clock-sh4-202.c + * + * Additional SH4-202 support for the clock framework + * + * Copyright (C) 2005 Paul Mundt + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/clkdev.h> +#include <asm/clock.h> +#include <asm/freq.h> + +#define CPG2_FRQCR3 0xfe0a0018 + +static int frqcr3_divisors[] = { 1, 2, 3, 4, 6, 8, 16 }; +static int frqcr3_values[] = { 0, 1, 2, 3, 4, 5, 6 }; + +static unsigned long emi_clk_recalc(struct clk *clk) +{ + int idx = __raw_readl(CPG2_FRQCR3) & 0x0007; + return clk->parent->rate / frqcr3_divisors[idx]; +} + +static inline int frqcr3_lookup(struct clk *clk, unsigned long rate) +{ + int divisor = clk->parent->rate / rate; + int i; + + for (i = 0; i < ARRAY_SIZE(frqcr3_divisors); i++) + if (frqcr3_divisors[i] == divisor) + return frqcr3_values[i]; + + /* Safe fallback */ + return 5; +} + +static struct sh_clk_ops sh4202_emi_clk_ops = { + .recalc = emi_clk_recalc, +}; + +static struct clk sh4202_emi_clk = { + .flags = CLK_ENABLE_ON_INIT, + .ops = &sh4202_emi_clk_ops, +}; + +static unsigned long femi_clk_recalc(struct clk *clk) +{ + int idx = (__raw_readl(CPG2_FRQCR3) >> 3) & 0x0007; + return clk->parent->rate / frqcr3_divisors[idx]; +} + +static struct sh_clk_ops sh4202_femi_clk_ops = { + .recalc = femi_clk_recalc, +}; + +static struct clk sh4202_femi_clk = { + .flags = CLK_ENABLE_ON_INIT, + .ops = &sh4202_femi_clk_ops, +}; + +static void shoc_clk_init(struct clk *clk) +{ + int i; + + /* + * For some reason, the shoc_clk seems to be set to some really + * insane value at boot (values outside of the allowable frequency + * range for instance). We deal with this by scaling it back down + * to something sensible just in case. + * + * Start scaling from the high end down until we find something + * that passes rate verification.. + */ + for (i = 0; i < ARRAY_SIZE(frqcr3_divisors); i++) { + int divisor = frqcr3_divisors[i]; + + if (clk->ops->set_rate(clk, clk->parent->rate / divisor) == 0) + break; + } + + WARN_ON(i == ARRAY_SIZE(frqcr3_divisors)); /* Undefined clock */ +} + +static unsigned long shoc_clk_recalc(struct clk *clk) +{ + int idx = (__raw_readl(CPG2_FRQCR3) >> 6) & 0x0007; + return clk->parent->rate / frqcr3_divisors[idx]; +} + +static int shoc_clk_verify_rate(struct clk *clk, unsigned long rate) +{ + struct clk *bclk = clk_get(NULL, "bus_clk"); + unsigned long bclk_rate = clk_get_rate(bclk); + + clk_put(bclk); + + if (rate > bclk_rate) + return 1; + if (rate > 66000000) + return 1; + + return 0; +} + +static int shoc_clk_set_rate(struct clk *clk, unsigned long rate) +{ + unsigned long frqcr3; + unsigned int tmp; + + /* Make sure we have something sensible to switch to */ + if (shoc_clk_verify_rate(clk, rate) != 0) + return -EINVAL; + + tmp = frqcr3_lookup(clk, rate); + + frqcr3 = __raw_readl(CPG2_FRQCR3); + frqcr3 &= ~(0x0007 << 6); + frqcr3 |= tmp << 6; + __raw_writel(frqcr3, CPG2_FRQCR3); + + clk->rate = clk->parent->rate / frqcr3_divisors[tmp]; + + return 0; +} + +static struct sh_clk_ops sh4202_shoc_clk_ops = { + .init = shoc_clk_init, + .recalc = shoc_clk_recalc, + .set_rate = shoc_clk_set_rate, +}; + +static struct clk sh4202_shoc_clk = { + .flags = CLK_ENABLE_ON_INIT, + .ops = &sh4202_shoc_clk_ops, +}; + +static struct clk *sh4202_onchip_clocks[] = { + &sh4202_emi_clk, + &sh4202_femi_clk, + &sh4202_shoc_clk, +}; + +static struct clk_lookup lookups[] = { + /* main clocks */ + CLKDEV_CON_ID("emi_clk", &sh4202_emi_clk), + CLKDEV_CON_ID("femi_clk", &sh4202_femi_clk), + CLKDEV_CON_ID("shoc_clk", &sh4202_shoc_clk), +}; + +int __init arch_clk_init(void) +{ + struct clk *clk; + int i, ret = 0; + + cpg_clk_init(); + + clk = clk_get(NULL, "master_clk"); + for (i = 0; i < ARRAY_SIZE(sh4202_onchip_clocks); i++) { + struct clk *clkp = sh4202_onchip_clocks[i]; + + clkp->parent = clk; + ret |= clk_register(clkp); + } + + clk_put(clk); + + clkdev_add_table(lookups, ARRAY_SIZE(lookups)); + + return ret; +} |