/*
* 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,
ðer_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;
}
