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-rw-r--r--arch/arm/mach-at91/clock.c640
1 files changed, 640 insertions, 0 deletions
diff --git a/arch/arm/mach-at91/clock.c b/arch/arm/mach-at91/clock.c
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index 00000000000..06c9a0507d0
--- /dev/null
+++ b/arch/arm/mach-at91/clock.c
@@ -0,0 +1,640 @@
+/*
+ * 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 const 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;
+}
+
+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,
+ * 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_SCER, AT91RM9200_PMC_MCKUDP);
+ } else if (cpu_is_at91sam9260() || cpu_is_at91sam9261() || cpu_is_at91sam9263()) {
+ uhpck.pmc_mask = AT91SAM926x_PMC_UHP;
+ udpck.pmc_mask = 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);
+
+ return 0;
+}
+
+/*
+ * Several unused clocks may be active. Turn them off.
+ */
+static int __init at91_clock_reset(void)
+{
+ unsigned long pcdr = 0;
+ unsigned long scdr = 0;
+ struct clk *clk;
+
+ list_for_each_entry(clk, &clocks, node) {
+ if (clk->users > 0)
+ continue;
+
+ if (clk->mode == pmc_periph_mode)
+ pcdr |= clk->pmc_mask;
+
+ if (clk->mode == pmc_sys_mode)
+ scdr |= clk->pmc_mask;
+
+ pr_debug("Clocks: disable unused %s\n", clk->name);
+ }
+
+ at91_sys_write(AT91_PMC_PCDR, pcdr);
+ at91_sys_write(AT91_PMC_SCDR, scdr);
+
+ return 0;
+}
+late_initcall(at91_clock_reset);
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