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 | 179 |
1 files changed, 179 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 00000000000..bfdf5fe8d94 --- /dev/null +++ b/arch/sh/kernel/cpu/sh4/clock-sh4-202.c @@ -0,0 +1,179 @@ +/* + * 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 <asm/clock.h> +#include <asm/freq.h> +#include <asm/io.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 void emi_clk_recalc(struct clk *clk) +{ + int idx = ctrl_inl(CPG2_FRQCR3) & 0x0007; + clk->rate = 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 clk_ops sh4202_emi_clk_ops = { + .recalc = emi_clk_recalc, +}; + +static struct clk sh4202_emi_clk = { + .name = "emi_clk", + .flags = CLK_ALWAYS_ENABLED, + .ops = &sh4202_emi_clk_ops, +}; + +static void femi_clk_recalc(struct clk *clk) +{ + int idx = (ctrl_inl(CPG2_FRQCR3) >> 3) & 0x0007; + clk->rate = clk->parent->rate / frqcr3_divisors[idx]; +} + +static struct clk_ops sh4202_femi_clk_ops = { + .recalc = femi_clk_recalc, +}; + +static struct clk sh4202_femi_clk = { + .name = "femi_clk", + .flags = CLK_ALWAYS_ENABLED, + .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 void shoc_clk_recalc(struct clk *clk) +{ + int idx = (ctrl_inl(CPG2_FRQCR3) >> 6) & 0x0007; + clk->rate = clk->parent->rate / frqcr3_divisors[idx]; +} + +static int shoc_clk_verify_rate(struct clk *clk, unsigned long rate) +{ + struct clk *bclk = clk_get("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 = ctrl_inl(CPG2_FRQCR3); + frqcr3 &= ~(0x0007 << 6); + frqcr3 |= tmp << 6; + ctrl_outl(frqcr3, CPG2_FRQCR3); + + clk->rate = clk->parent->rate / frqcr3_divisors[tmp]; + + return 0; +} + +static struct 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 = { + .name = "shoc_clk", + .flags = CLK_ALWAYS_ENABLED, + .ops = &sh4202_shoc_clk_ops, +}; + +static struct clk *sh4202_onchip_clocks[] = { + &sh4202_emi_clk, + &sh4202_femi_clk, + &sh4202_shoc_clk, +}; + +static int __init sh4202_clk_init(void) +{ + struct clk *clk = clk_get("master_clk"); + int i; + + for (i = 0; i < ARRAY_SIZE(sh4202_onchip_clocks); i++) { + struct clk *clkp = sh4202_onchip_clocks[i]; + + clkp->parent = clk; + clk_register(clkp); + clk_enable(clkp); + } + + /* + * Now that we have the rest of the clocks registered, we need to + * force the parent clock to propagate so that these clocks will + * automatically figure out their rate. We cheat by handing the + * parent clock its current rate and forcing child propagation. + */ + clk_set_rate(clk, clk_get_rate(clk)); + + clk_put(clk); + + return 0; +} + +arch_initcall(sh4202_clk_init); + |