diff options
author | Andrew Victor <andrew@sanpeople.com> | 2007-02-05 11:42:07 +0100 |
---|---|---|
committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2007-02-08 14:50:56 +0000 |
commit | 9d0412680e6c7b685ee466842047bcfb924d6dc5 (patch) | |
tree | c79300964ef1aca5d24571696f95e76b37c14679 /arch/arm/mach-at91/clock.c | |
parent | a93d48cc6019f84394b31d10c0d830a3b71696be (diff) | |
download | linux-9d0412680e6c7b685ee466842047bcfb924d6dc5.tar.bz2 |
[ARM] 4124/1: Rename mach-at91rm9200 and arch-at91rm9200 directories
Now that Linux includes support for the Atmel AT91SAM9260 and
AT91SAM9261 processors in addition to the original Atmel AT91RM9200
(with support for more AT91 processors pending), the "mach-at91rm9200"
and "arch-at91rm9200" directories should be renamed to indicate their
more generic nature.
The following git commands should be run BEFORE applying this patch:
git-mv arch/arm/mach-at91rm9200 arch/arm/mach-at91
git-mv include/asm-arm/arch-at91rm9200 include/asm-arm/arch-at91
Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mach-at91/clock.c')
-rw-r--r-- | arch/arm/mach-at91/clock.c | 644 |
1 files changed, 644 insertions, 0 deletions
diff --git a/arch/arm/mach-at91/clock.c b/arch/arm/mach-at91/clock.c new file mode 100644 index 000000000000..baab095f6e32 --- /dev/null +++ b/arch/arm/mach-at91/clock.c @@ -0,0 +1,644 @@ +/* + * linux/arch/arm/mach-at91/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/hardware.h> +#include <asm/arch/at91_pmc.h> +#include <asm/arch/cpu.h> + +#include "clock.h" + + +/* + * 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. + */ + +#define clk_is_primary(x) ((x)->type & CLK_TYPE_PRIMARY) +#define clk_is_programmable(x) ((x)->type & CLK_TYPE_PROGRAMMABLE) +#define clk_is_peripheral(x) ((x)->type & CLK_TYPE_PERIPHERAL) +#define clk_is_sys(x) ((x)->type & CLK_TYPE_SYSTEM) + + +static LIST_HEAD(clocks); +static DEFINE_SPINLOCK(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, + .type = CLK_TYPE_PRIMARY, +}; +static struct clk main_clk = { + .name = "main", + .pmc_mask = AT91_PMC_MOSCS, /* in PMC_SR */ + .id = 1, + .type = CLK_TYPE_PRIMARY, +}; +static struct clk plla = { + .name = "plla", + .parent = &main_clk, + .pmc_mask = AT91_PMC_LOCKA, /* in PMC_SR */ + .id = 2, + .type = CLK_TYPE_PRIMARY | CLK_TYPE_PLL, +}; + +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; + + // REVISIT: Add work-around for AT91RM9200 Errata #26 ? + 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 = AT91_PMC_LOCKB, /* in PMC_SR */ + .mode = pllb_mode, + .id = 3, + .type = CLK_TYPE_PRIMARY | CLK_TYPE_PLL, +}; + +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, + .mode = pmc_sys_mode, +}; +static struct clk uhpck = { + .name = "uhpck", + .parent = &pllb, + .mode = pmc_sys_mode, +}; + + +/* + * 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 = AT91_PMC_MCKRDY, /* in PMC_SR */ +}; + +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 __init *at91_css_to_clk(unsigned long css) +{ + switch (css) { + case AT91_PMC_CSS_SLOW: + return &clk32k; + case AT91_PMC_CSS_MAIN: + return &main_clk; + case AT91_PMC_CSS_PLLA: + return &plla; + case AT91_PMC_CSS_PLLB: + return &pllb; + } + + return NULL; +} + +/* + * Associate a particular clock with a function (eg, "uart") and device. + * The drivers can then request the same 'function' with several different + * devices and not care about which clock name to use. + */ +void __init at91_clock_associate(const char *id, struct device *dev, const char *func) +{ + struct clk *clk = clk_get(NULL, id); + + if (!dev || !clk || !IS_ERR(clk_get(dev, func))) + return; + + clk->function = func; + clk->dev = dev; +} + +/* clocks cannot be de-registered no refcounting necessary */ +struct clk *clk_get(struct device *dev, const char *id) +{ + struct clk *clk; + + list_for_each_entry(clk, &clocks, node) { + if (strcmp(id, clk->name) == 0) + return clk; + if (clk->function && (dev == clk->dev) && strcmp(id, clk->function) == 0) + return clk; + } + + 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_is_programmable(clk)) + 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_is_programmable(clk)) + 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 &= AT91_PMC_CSS_PLLB; /* clock selection */ + 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 (!clk_is_primary(parent) || !clk_is_programmable(clk)) + 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); + +/* establish PCK0..PCK3 parentage and rate */ +static void init_programmable_clock(struct clk *clk) +{ + struct clk *parent; + u32 pckr; + + pckr = at91_sys_read(AT91_PMC_PCKR(clk->id)); + parent = at91_css_to_clk(pckr & AT91_PMC_CSS); + clk->parent = parent; + clk->rate_hz = parent->rate_hz / (1 << ((pckr >> 2) & 3)); +} + +#endif /* CONFIG_AT91_PROGRAMMABLE_CLOCKS */ + +/*------------------------------------------------------------------------*/ + +#ifdef CONFIG_DEBUG_FS + +static int at91_clk_show(struct seq_file *s, void *unused) +{ + u32 scsr, pcsr, sr; + struct clk *clk; + 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"); + + list_for_each_entry(clk, &clocks, node) { + char *state; + + 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=%2d %-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 + +/*------------------------------------------------------------------------*/ + +/* Register a new clock */ +int __init clk_register(struct clk *clk) +{ + if (clk_is_peripheral(clk)) { + clk->parent = &mck; + clk->mode = pmc_periph_mode; + list_add_tail(&clk->node, &clocks); + } + else if (clk_is_sys(clk)) { + clk->parent = &mck; + clk->mode = pmc_sys_mode; + + list_add_tail(&clk->node, &clocks); + } +#ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS + else if (clk_is_programmable(clk)) { + clk->mode = pmc_sys_mode; + init_programmable_clock(clk); + list_add_tail(&clk->node, &clocks); + } +#endif + + return 0; +} + + +/*------------------------------------------------------------------------*/ + +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; + + return freq; +} + +static u32 __init at91_usb_rate(struct clk *pll, u32 freq, u32 reg) +{ + if (pll == &pllb && (reg & AT91_PMC_USB96M)) + return freq / 2; + else + 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; +} + +/* + * Several unused clocks may be active. Turn them off. + */ +static void __init at91_periphclk_reset(void) +{ + unsigned long reg; + struct clk *clk; + + reg = at91_sys_read(AT91_PMC_PCSR); + + list_for_each_entry(clk, &clocks, node) { + if (clk->mode != pmc_periph_mode) + continue; + + if (clk->users > 0) + reg &= ~clk->pmc_mask; + } + + at91_sys_write(AT91_PMC_PCDR, reg); +} + +static struct clk *const standard_pmc_clocks[] __initdata = { + /* four primary clocks */ + &clk32k, + &main_clk, + &plla, + &pllb, + + /* PLLB children (USB) */ + &udpck, + &uhpck, + + /* MCK */ + &mck +}; + +int __init at91_clock_init(unsigned long main_clock) +{ + unsigned tmp, freq, mckr; + int i; + + /* + * 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 & AT91_PMC_MAINRDY)); + main_clock = (tmp & AT91_PMC_MAINF) * (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) | AT91_PMC_USB96M; + pllb.rate_hz = at91_pll_rate(&pllb, main_clock, at91_pllb_usb_init); + if (cpu_is_at91rm9200()) { + uhpck.pmc_mask = AT91RM9200_PMC_UHP; + udpck.pmc_mask = AT91RM9200_PMC_UDP; + at91_sys_write(AT91_PMC_SCDR, AT91RM9200_PMC_UHP | AT91RM9200_PMC_UDP); + at91_sys_write(AT91_PMC_SCER, AT91RM9200_PMC_MCKUDP); + } else if (cpu_is_at91sam9260()) { + uhpck.pmc_mask = AT91SAM926x_PMC_UHP; + udpck.pmc_mask = AT91SAM926x_PMC_UDP; + at91_sys_write(AT91_PMC_SCDR, AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP); + } else if (cpu_is_at91sam9261()) { + uhpck.pmc_mask = (AT91SAM926x_PMC_UHP | AT91_PMC_HCK0); + udpck.pmc_mask = AT91SAM926x_PMC_UDP; + at91_sys_write(AT91_PMC_SCDR, AT91SAM926x_PMC_UHP | AT91_PMC_HCK0 | AT91SAM926x_PMC_UDP); + } + at91_sys_write(AT91_CKGR_PLLBR, 0); + + udpck.rate_hz = at91_usb_rate(&pllb, pllb.rate_hz, at91_pllb_usb_init); + uhpck.rate_hz = at91_usb_rate(&pllb, pllb.rate_hz, at91_pllb_usb_init); + + /* + * 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 = at91_css_to_clk(mckr & AT91_PMC_CSS); + freq = mck.parent->rate_hz; + freq /= (1 << ((mckr >> 2) & 3)); /* prescale */ + mck.rate_hz = freq / (1 + ((mckr >> 8) & 3)); /* mdiv */ + + /* Register the PMC's standard clocks */ + for (i = 0; i < ARRAY_SIZE(standard_pmc_clocks); i++) + list_add_tail(&standard_pmc_clocks[i]->node, &clocks); + + /* MCK and CPU clock are "always on" */ + clk_enable(&mck); + + 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); + + /* disable all programmable clocks */ + at91_sys_write(AT91_PMC_SCDR, AT91_PMC_PCK0 | AT91_PMC_PCK1 | AT91_PMC_PCK2 | AT91_PMC_PCK3); + + /* disable all other unused peripheral clocks */ + at91_periphclk_reset(); + + return 0; +} |