X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Farm%2Fmach-at91rm9200%2Fclock.c;fp=arch%2Farm%2Fmach-at91rm9200%2Fclock.c;h=8b95467c6d6170566d55c2b6dfed9c7bdbb4a8f2;hb=16cf0ec7408f389279d413869e94c1a351392f97;hp=0000000000000000000000000000000000000000;hpb=65da6b7c3bf0bd6a149128079565e5f4efec28ac;p=linux-2.6.git

diff --git a/arch/arm/mach-at91rm9200/clock.c b/arch/arm/mach-at91rm9200/clock.c
new file mode 100644
index 000000000..8b95467c6
--- /dev/null
+++ b/arch/arm/mach-at91rm9200/clock.c
@@ -0,0 +1,681 @@
+/*
+ * 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 ether_clk = {
+	.name		= "ether_clk",
+	.parent		= &mck,
+	.pmc_mask	= 1 << AT91_ID_EMAC,
+	.mode		= pmc_periph_mode,
+};
+static struct clk mmc_clk = {
+	.name		= "mci_clk",
+	.parent		= &mck,
+	.pmc_mask	= 1 << AT91_ID_MCI,
+	.mode		= pmc_periph_mode,
+};
+static struct clk twi_clk = {
+	.name		= "twi_clk",
+	.parent		= &mck,
+	.pmc_mask	= 1 << AT91_ID_TWI,
+	.mode		= pmc_periph_mode,
+};
+static struct clk usart0_clk = {
+	.name		= "usart0_clk",
+	.parent		= &mck,
+	.pmc_mask	= 1 << AT91_ID_US0,
+	.mode		= pmc_periph_mode,
+};
+static struct clk usart1_clk = {
+	.name		= "usart1_clk",
+	.parent		= &mck,
+	.pmc_mask	= 1 << AT91_ID_US1,
+	.mode		= pmc_periph_mode,
+};
+static struct clk usart2_clk = {
+	.name		= "usart2_clk",
+	.parent		= &mck,
+	.pmc_mask	= 1 << AT91_ID_US2,
+	.mode		= pmc_periph_mode,
+};
+static struct clk usart3_clk = {
+	.name		= "usart3_clk",
+	.parent		= &mck,
+	.pmc_mask	= 1 << AT91_ID_US3,
+	.mode		= pmc_periph_mode,
+};
+static struct clk spi_clk = {
+	.name		= "spi0_clk",
+	.parent		= &mck,
+	.pmc_mask	= 1 << AT91_ID_SPI,
+	.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_clk,
+	&usart1_clk,
+	&usart2_clk,
+	&usart3_clk,
+	&mmc_clk,
+	&udc_clk,
+	&twi_clk,
+	&spi_clk,
+	// ssc0..ssc2
+	// tc0..tc5
+	&ohci_clk,
+	&ether_clk,
+};
+
+
+/* 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 &= 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 (!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=%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
+
+/*------------------------------------------------------------------------*/
+
+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;
+}
+
+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 & 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);
+	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);
+
+	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 = 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;
+}