diff options
Diffstat (limited to 'arch/arm/mach-at91rm9200/clock.c')
| -rw-r--r-- | arch/arm/mach-at91rm9200/clock.c | 620 |
1 files changed, 620 insertions, 0 deletions
diff --git a/arch/arm/mach-at91rm9200/clock.c b/arch/arm/mach-at91rm9200/clock.c new file mode 100644 index 00000000000..ec8195a2a3c --- /dev/null +++ b/arch/arm/mach-at91rm9200/clock.c @@ -0,0 +1,620 @@ +/* + * linux/arch/arm/mach-at91rm9200/clock.c + * + * Copyright (C) 2005 David Brownell + * Copyright (C) 2005 Ivan Kokshaysky + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/fs.h> +#include <linux/debugfs.h> +#include <linux/seq_file.h> +#include <linux/list.h> +#include <linux/errno.h> +#include <linux/err.h> +#include <linux/spinlock.h> +#include <linux/delay.h> +#include <linux/clk.h> + +#include <asm/semaphore.h> +#include <asm/io.h> +#include <asm/mach-types.h> + +#include <asm/arch/hardware.h> +#include <asm/arch/board.h> /* for master clock global */ + +#include "generic.h" + +#undef DEBUG + +/* + * There's a lot more which can be done with clocks, including cpufreq + * integration, slow clock mode support (for system suspend), letting + * PLLB be used at other rates (on boards that don't need USB), etc. + */ + +struct clk { + const char *name; + unsigned long rate_hz; + struct clk *parent; + u32 pmc_mask; + void (*mode)(struct clk *, int); + unsigned id:2; /* PCK0..3, or 32k/main/a/b */ + unsigned primary:1; + unsigned pll:1; + unsigned programmable:1; + u16 users; +}; + +static spinlock_t clk_lock; +static u32 at91_pllb_usb_init; + +/* + * Four primary clock sources: two crystal oscillators (32K, main), and + * two PLLs. PLLA usually runs the master clock; and PLLB must run at + * 48 MHz (unless no USB function clocks are needed). The main clock and + * both PLLs are turned off to run in "slow clock mode" (system suspend). + */ +static struct clk clk32k = { + .name = "clk32k", + .rate_hz = AT91_SLOW_CLOCK, + .users = 1, /* always on */ + .id = 0, + .primary = 1, +}; +static struct clk main_clk = { + .name = "main", + .pmc_mask = 1 << 0, /* in PMC_SR */ + .users = 1, + .id = 1, + .primary = 1, +}; +static struct clk plla = { + .name = "plla", + .parent = &main_clk, + .pmc_mask = 1 << 1, /* in PMC_SR */ + .id = 2, + .primary = 1, + .pll = 1, +}; + +static void pllb_mode(struct clk *clk, int is_on) +{ + u32 value; + + if (is_on) { + is_on = AT91_PMC_LOCKB; + value = at91_pllb_usb_init; + } else + value = 0; + + at91_sys_write(AT91_CKGR_PLLBR, value); + + do { + cpu_relax(); + } while ((at91_sys_read(AT91_PMC_SR) & AT91_PMC_LOCKB) != is_on); +} + +static struct clk pllb = { + .name = "pllb", + .parent = &main_clk, + .pmc_mask = 1 << 2, /* in PMC_SR */ + .mode = pllb_mode, + .id = 3, + .primary = 1, + .pll = 1, +}; + +static void pmc_sys_mode(struct clk *clk, int is_on) +{ + if (is_on) + at91_sys_write(AT91_PMC_SCER, clk->pmc_mask); + else + at91_sys_write(AT91_PMC_SCDR, clk->pmc_mask); +} + +/* USB function clocks (PLLB must be 48 MHz) */ +static struct clk udpck = { + .name = "udpck", + .parent = &pllb, + .pmc_mask = AT91_PMC_UDP, + .mode = pmc_sys_mode, +}; +static struct clk uhpck = { + .name = "uhpck", + .parent = &pllb, + .pmc_mask = AT91_PMC_UHP, + .mode = pmc_sys_mode, +}; + +#ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS +/* + * The four programmable clocks can be parented by any primary clock. + * You must configure pin multiplexing to bring these signals out. + */ +static struct clk pck0 = { + .name = "pck0", + .pmc_mask = AT91_PMC_PCK0, + .mode = pmc_sys_mode, + .programmable = 1, + .id = 0, +}; +static struct clk pck1 = { + .name = "pck1", + .pmc_mask = AT91_PMC_PCK1, + .mode = pmc_sys_mode, + .programmable = 1, + .id = 1, +}; +static struct clk pck2 = { + .name = "pck2", + .pmc_mask = AT91_PMC_PCK2, + .mode = pmc_sys_mode, + .programmable = 1, + .id = 2, +}; +static struct clk pck3 = { + .name = "pck3", + .pmc_mask = AT91_PMC_PCK3, + .mode = pmc_sys_mode, + .programmable = 1, + .id = 3, +}; +#endif /* CONFIG_AT91_PROGRAMMABLE_CLOCKS */ + + +/* + * The master clock is divided from the CPU clock (by 1-4). It's used for + * memory, interfaces to on-chip peripherals, the AIC, and sometimes more + * (e.g baud rate generation). It's sourced from one of the primary clocks. + */ +static struct clk mck = { + .name = "mck", + .pmc_mask = 1 << 3, /* in PMC_SR */ + .users = 1, /* (must be) always on */ +}; + +static void pmc_periph_mode(struct clk *clk, int is_on) +{ + if (is_on) + at91_sys_write(AT91_PMC_PCER, clk->pmc_mask); + else + at91_sys_write(AT91_PMC_PCDR, clk->pmc_mask); +} + +static struct clk udc_clk = { + .name = "udc_clk", + .parent = &mck, + .pmc_mask = 1 << AT91_ID_UDP, + .mode = pmc_periph_mode, +}; +static struct clk ohci_clk = { + .name = "ohci_clk", + .parent = &mck, + .pmc_mask = 1 << AT91_ID_UHP, + .mode = pmc_periph_mode, +}; + +static struct clk *const clock_list[] = { + /* four primary clocks -- MUST BE FIRST! */ + &clk32k, + &main_clk, + &plla, + &pllb, + + /* PLLB children (USB) */ + &udpck, + &uhpck, + +#ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS + /* programmable clocks */ + &pck0, + &pck1, + &pck2, + &pck3, +#endif /* CONFIG_AT91_PROGRAMMABLE_CLOCKS */ + + /* MCK and peripherals */ + &mck, + // usart0..usart3 + // mmc + &udc_clk, + // i2c + // spi + // ssc0..ssc2 + // tc0..tc5 + &ohci_clk, + // ether +}; + + +/* clocks are all static for now; no refcounting necessary */ +struct clk *clk_get(struct device *dev, const char *id) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(clock_list); i++) { + if (strcmp(id, clock_list[i]->name) == 0) + return clock_list[i]; + } + + return ERR_PTR(-ENOENT); +} +EXPORT_SYMBOL(clk_get); + +void clk_put(struct clk *clk) +{ +} +EXPORT_SYMBOL(clk_put); + +static void __clk_enable(struct clk *clk) +{ + if (clk->parent) + __clk_enable(clk->parent); + if (clk->users++ == 0 && clk->mode) + clk->mode(clk, 1); +} + +int clk_enable(struct clk *clk) +{ + unsigned long flags; + + spin_lock_irqsave(&clk_lock, flags); + __clk_enable(clk); + spin_unlock_irqrestore(&clk_lock, flags); + return 0; +} +EXPORT_SYMBOL(clk_enable); + +static void __clk_disable(struct clk *clk) +{ + BUG_ON(clk->users == 0); + if (--clk->users == 0 && clk->mode) + clk->mode(clk, 0); + if (clk->parent) + __clk_disable(clk->parent); +} + +void clk_disable(struct clk *clk) +{ + unsigned long flags; + + spin_lock_irqsave(&clk_lock, flags); + __clk_disable(clk); + spin_unlock_irqrestore(&clk_lock, flags); +} +EXPORT_SYMBOL(clk_disable); + +unsigned long clk_get_rate(struct clk *clk) +{ + unsigned long flags; + unsigned long rate; + + spin_lock_irqsave(&clk_lock, flags); + for (;;) { + rate = clk->rate_hz; + if (rate || !clk->parent) + break; + clk = clk->parent; + } + spin_unlock_irqrestore(&clk_lock, flags); + return rate; +} +EXPORT_SYMBOL(clk_get_rate); + +/*------------------------------------------------------------------------*/ + +#ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS + +/* + * For now, only the programmable clocks support reparenting (MCK could + * do this too, with care) or rate changing (the PLLs could do this too, + * ditto MCK but that's more for cpufreq). Drivers may reparent to get + * a better rate match; we don't. + */ + +long clk_round_rate(struct clk *clk, unsigned long rate) +{ + unsigned long flags; + unsigned prescale; + unsigned long actual; + + if (!clk->programmable) + return -EINVAL; + spin_lock_irqsave(&clk_lock, flags); + + actual = clk->parent->rate_hz; + for (prescale = 0; prescale < 7; prescale++) { + if (actual && actual <= rate) + break; + actual >>= 1; + } + + spin_unlock_irqrestore(&clk_lock, flags); + return (prescale < 7) ? actual : -ENOENT; +} +EXPORT_SYMBOL(clk_round_rate); + +int clk_set_rate(struct clk *clk, unsigned long rate) +{ + unsigned long flags; + unsigned prescale; + unsigned long actual; + + if (!clk->programmable) + return -EINVAL; + if (clk->users) + return -EBUSY; + spin_lock_irqsave(&clk_lock, flags); + + actual = clk->parent->rate_hz; + for (prescale = 0; prescale < 7; prescale++) { + if (actual && actual <= rate) { + u32 pckr; + + pckr = at91_sys_read(AT91_PMC_PCKR(clk->id)); + pckr &= 0x03; + pckr |= prescale << 2; + at91_sys_write(AT91_PMC_PCKR(clk->id), pckr); + clk->rate_hz = actual; + break; + } + actual >>= 1; + } + + spin_unlock_irqrestore(&clk_lock, flags); + return (prescale < 7) ? actual : -ENOENT; +} +EXPORT_SYMBOL(clk_set_rate); + +struct clk *clk_get_parent(struct clk *clk) +{ + return clk->parent; +} +EXPORT_SYMBOL(clk_get_parent); + +int clk_set_parent(struct clk *clk, struct clk *parent) +{ + unsigned long flags; + + if (clk->users) + return -EBUSY; + if (!parent->primary || !clk->programmable) + return -EINVAL; + spin_lock_irqsave(&clk_lock, flags); + + clk->rate_hz = parent->rate_hz; + clk->parent = parent; + at91_sys_write(AT91_PMC_PCKR(clk->id), parent->id); + + spin_unlock_irqrestore(&clk_lock, flags); + return 0; +} +EXPORT_SYMBOL(clk_set_parent); + +#endif /* CONFIG_AT91_PROGRAMMABLE_CLOCKS */ + +/*------------------------------------------------------------------------*/ + +#ifdef CONFIG_DEBUG_FS + +static int at91_clk_show(struct seq_file *s, void *unused) +{ + u32 scsr, pcsr, sr; + unsigned i; + + seq_printf(s, "SCSR = %8x\n", scsr = at91_sys_read(AT91_PMC_SCSR)); + seq_printf(s, "PCSR = %8x\n", pcsr = at91_sys_read(AT91_PMC_PCSR)); + + seq_printf(s, "MOR = %8x\n", at91_sys_read(AT91_CKGR_MOR)); + seq_printf(s, "MCFR = %8x\n", at91_sys_read(AT91_CKGR_MCFR)); + seq_printf(s, "PLLA = %8x\n", at91_sys_read(AT91_CKGR_PLLAR)); + seq_printf(s, "PLLB = %8x\n", at91_sys_read(AT91_CKGR_PLLBR)); + + seq_printf(s, "MCKR = %8x\n", at91_sys_read(AT91_PMC_MCKR)); + for (i = 0; i < 4; i++) + seq_printf(s, "PCK%d = %8x\n", i, at91_sys_read(AT91_PMC_PCKR(i))); + seq_printf(s, "SR = %8x\n", sr = at91_sys_read(AT91_PMC_SR)); + + seq_printf(s, "\n"); + + for (i = 0; i < ARRAY_SIZE(clock_list); i++) { + char *state; + struct clk *clk = clock_list[i]; + + if (clk->mode == pmc_sys_mode) + state = (scsr & clk->pmc_mask) ? "on" : "off"; + else if (clk->mode == pmc_periph_mode) + state = (pcsr & clk->pmc_mask) ? "on" : "off"; + else if (clk->pmc_mask) + state = (sr & clk->pmc_mask) ? "on" : "off"; + else if (clk == &clk32k || clk == &main_clk) + state = "on"; + else + state = ""; + + seq_printf(s, "%-10s users=%d %-3s %9ld Hz %s\n", + clk->name, clk->users, state, clk_get_rate(clk), + clk->parent ? clk->parent->name : ""); + } + return 0; +} + +static int at91_clk_open(struct inode *inode, struct file *file) +{ + return single_open(file, at91_clk_show, NULL); +} + +static struct file_operations at91_clk_operations = { + .open = at91_clk_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static int __init at91_clk_debugfs_init(void) +{ + /* /sys/kernel/debug/at91_clk */ + (void) debugfs_create_file("at91_clk", S_IFREG | S_IRUGO, NULL, NULL, &at91_clk_operations); + + return 0; +} +postcore_initcall(at91_clk_debugfs_init); + +#endif + +/*------------------------------------------------------------------------*/ + +static u32 __init at91_pll_rate(struct clk *pll, u32 freq, u32 reg) +{ + unsigned mul, div; + + div = reg & 0xff; + mul = (reg >> 16) & 0x7ff; + if (div && mul) { + freq /= div; + freq *= mul + 1; + } else + freq = 0; + if (pll == &pllb && (reg & (1 << 28))) + freq /= 2; + return freq; +} + +static unsigned __init at91_pll_calc(unsigned main_freq, unsigned out_freq) +{ + unsigned i, div = 0, mul = 0, diff = 1 << 30; + unsigned ret = (out_freq > 155000000) ? 0xbe00 : 0x3e00; + + /* PLL output max 240 MHz (or 180 MHz per errata) */ + if (out_freq > 240000000) + goto fail; + + for (i = 1; i < 256; i++) { + int diff1; + unsigned input, mul1; + + /* + * PLL input between 1MHz and 32MHz per spec, but lower + * frequences seem necessary in some cases so allow 100K. + */ + input = main_freq / i; + if (input < 100000) + continue; + if (input > 32000000) + continue; + + mul1 = out_freq / input; + if (mul1 > 2048) + continue; + if (mul1 < 2) + goto fail; + + diff1 = out_freq - input * mul1; + if (diff1 < 0) + diff1 = -diff1; + if (diff > diff1) { + diff = diff1; + div = i; + mul = mul1; + if (diff == 0) + break; + } + } + if (i == 256 && diff > (out_freq >> 5)) + goto fail; + return ret | ((mul - 1) << 16) | div; +fail: + return 0; +} + +int __init at91_clock_init(unsigned long main_clock) +{ + unsigned tmp, freq, mckr; + + spin_lock_init(&clk_lock); + + /* + * When the bootloader initialized the main oscillator correctly, + * there's no problem using the cycle counter. But if it didn't, + * or when using oscillator bypass mode, we must be told the speed + * of the main clock. + */ + if (!main_clock) { + do { + tmp = at91_sys_read(AT91_CKGR_MCFR); + } while (!(tmp & 0x10000)); + main_clock = (tmp & 0xffff) * (AT91_SLOW_CLOCK / 16); + } + main_clk.rate_hz = main_clock; + + /* report if PLLA is more than mildly overclocked */ + plla.rate_hz = at91_pll_rate(&plla, main_clock, at91_sys_read(AT91_CKGR_PLLAR)); + if (plla.rate_hz > 209000000) + pr_info("Clocks: PLLA overclocked, %ld MHz\n", plla.rate_hz / 1000000); + + /* + * USB clock init: choose 48 MHz PLLB value, turn all clocks off, + * disable 48MHz clock during usb peripheral suspend. + * + * REVISIT: assumes MCK doesn't derive from PLLB! + */ + at91_pllb_usb_init = at91_pll_calc(main_clock, 48000000 * 2) | 0x10000000; + pllb.rate_hz = at91_pll_rate(&pllb, main_clock, at91_pllb_usb_init); + at91_sys_write(AT91_PMC_PCDR, (1 << AT91_ID_UHP) | (1 << AT91_ID_UDP)); + at91_sys_write(AT91_PMC_SCDR, AT91_PMC_UHP | AT91_PMC_UDP); + at91_sys_write(AT91_CKGR_PLLBR, 0); + at91_sys_write(AT91_PMC_SCER, AT91_PMC_MCKUDP); + + /* + * MCK and CPU derive from one of those primary clocks. + * For now, assume this parentage won't change. + */ + mckr = at91_sys_read(AT91_PMC_MCKR); + mck.parent = clock_list[mckr & AT91_PMC_CSS]; + mck.parent->users++; + freq = mck.parent->rate_hz; + freq /= (1 << ((mckr >> 2) & 3)); /* prescale */ + mck.rate_hz = freq / (1 + ((mckr >> 8) & 3)); /* mdiv */ + + printk("Clocks: CPU %u MHz, master %u MHz, main %u.%03u MHz\n", + freq / 1000000, (unsigned) mck.rate_hz / 1000000, + (unsigned) main_clock / 1000000, + ((unsigned) main_clock % 1000000) / 1000); + + /* FIXME get rid of master_clock global */ + at91_master_clock = mck.rate_hz; + +#ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS + /* establish PCK0..PCK3 parentage */ + for (tmp = 0; tmp < ARRAY_SIZE(clock_list); tmp++) { + struct clk *clk = clock_list[tmp], *parent; + u32 pckr; + + if (!clk->programmable) + continue; + + pckr = at91_sys_read(AT91_PMC_PCKR(clk->id)); + parent = clock_list[pckr & 3]; + clk->parent = parent; + clk->rate_hz = parent->rate_hz / (1 << ((pckr >> 2) & 3)); + } +#else + /* disable unused clocks */ + at91_sys_write(AT91_PMC_SCDR, AT91_PMC_PCK0 | AT91_PMC_PCK1 | AT91_PMC_PCK2 | AT91_PMC_PCK3); +#endif /* CONFIG_AT91_PROGRAMMABLE_CLOCKS */ + + /* FIXME several unused clocks may still be active... provide + * a CONFIG option to turn off all unused clocks at some point + * before driver init starts. + */ + + return 0; +} |