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[ARM] 3578/1: AT91RM9200 Clock update 

Patch from Andrew Victor

Some updates to the clock infrastructure for the AT91RM9200.

1. Hard-coded values replaced with names defined in at91rm9200_sys.h.
2. Added the four PIO clocks, which are enabled at startup.
3. At startup, disable all unused clocks.
4. Minor bugfix for usage counts associated with MCK. [Patch from David
Brownell]
5. Added at91_clock_associate() function to associate device & function
with a particular clock.  [Patch from David Brownell]

Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Andrew Victor 2006-06-19 13:20:23 +01:00 committed by Russell King
parent b7408aff2d
commit 91f8ed835f
1 changed files with 101 additions and 20 deletions
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121
arch/arm/mach-at91rm9200/clock.c
View File

@ -32,8 +32,6 @@
#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
@ -41,7 +39,9 @@
*/
struct clk {
const char *name;
const char *name; /* unique clock name */
const char *function; /* function of the clock */
struct device *dev; /* device associated with function */
unsigned long rate_hz;
struct clk *parent;
u32 pmc_mask;
@ -71,15 +71,14 @@ static struct clk clk32k = {
};
static struct clk main_clk = {
.name = "main",
.pmc_mask = 1 << 0, /* in PMC_SR */
.users = 1,
.pmc_mask = AT91_PMC_MOSCS, /* in PMC_SR */
.id = 1,
.primary = 1,
};
static struct clk plla = {
.name = "plla",
.parent = &main_clk,
.pmc_mask = 1 << 1, /* in PMC_SR */
.pmc_mask = AT91_PMC_LOCKA, /* in PMC_SR */
.id = 2,
.primary = 1,
.pll = 1,
@ -105,7 +104,7 @@ static void pllb_mode(struct clk *clk, int is_on)
static struct clk pllb = {
.name = "pllb",
.parent = &main_clk,
.pmc_mask = 1 << 2, /* in PMC_SR */
.pmc_mask = AT91_PMC_LOCKB, /* in PMC_SR */
.mode = pllb_mode,
.id = 3,
.primary = 1,
@ -177,8 +176,7 @@ static struct clk pck3 = {
*/
static struct clk mck = {
.name = "mck",
.pmc_mask = 1 << 3, /* in PMC_SR */
.users = 1, /* (must be) always on */
.pmc_mask = AT91_PMC_MCKRDY, /* in PMC_SR */
};
static void pmc_periph_mode(struct clk *clk, int is_on)
@ -249,6 +247,30 @@ static struct clk spi_clk = {
.pmc_mask = 1 << AT91_ID_SPI,
.mode = pmc_periph_mode,
};
static struct clk pioA_clk = {
.name = "pioA_clk",
.parent = &mck,
.pmc_mask = 1 << AT91_ID_PIOA,
.mode = pmc_periph_mode,
};
static struct clk pioB_clk = {
.name = "pioB_clk",
.parent = &mck,
.pmc_mask = 1 << AT91_ID_PIOB,
.mode = pmc_periph_mode,
};
static struct clk pioC_clk = {
.name = "pioC_clk",
.parent = &mck,
.pmc_mask = 1 << AT91_ID_PIOC,
.mode = pmc_periph_mode,
};
static struct clk pioD_clk = {
.name = "pioD_clk",
.parent = &mck,
.pmc_mask = 1 << AT91_ID_PIOD,
.mode = pmc_periph_mode,
};
static struct clk *const clock_list[] = {
/* four primary clocks -- MUST BE FIRST! */
@ -279,21 +301,46 @@ static struct clk *const clock_list[] = {
&udc_clk,
&twi_clk,
&spi_clk,
&pioA_clk,
&pioB_clk,
&pioC_clk,
&pioD_clk,
// ssc0..ssc2
// tc0..tc5
// irq0..irq6
&ohci_clk,
&ether_clk,
};
/*
* 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 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];
struct clk *clk = clock_list[i];
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);
@ -593,6 +640,30 @@ fail:
return 0;
}
/*
* Several unused clocks may be active. Turn them off.
*/
static void at91_periphclk_reset(void)
{
unsigned long reg;
int i;
reg = at91_sys_read(AT91_PMC_PCSR);
for (i = 0; i < ARRAY_SIZE(clock_list); i++) {
struct clk *clk = clock_list[i];
if (clk->mode != pmc_periph_mode)
continue;
if (clk->users > 0)
reg &= ~clk->pmc_mask;
}
at91_sys_write(AT91_PMC_PCDR, reg);
}
int __init at91_clock_init(unsigned long main_clock)
{
unsigned tmp, freq, mckr;
@ -626,7 +697,6 @@ int __init at91_clock_init(unsigned long main_clock)
*/
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);
@ -640,11 +710,13 @@ int __init at91_clock_init(unsigned long main_clock)
*/
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 */
/* 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,
@ -663,19 +735,28 @@ int __init at91_clock_init(unsigned long main_clock)
continue;
pckr = at91_sys_read(AT91_PMC_PCKR(clk->id));
parent = clock_list[pckr & 3];
parent = clock_list[pckr & AT91_PMC_CSS];
clk->parent = parent;
clk->rate_hz = parent->rate_hz / (1 << ((pckr >> 2) & 3));
if (clk->users == 0) {
/* not being used, so switch it off */
at91_sys_write(AT91_PMC_SCDR, clk->pmc_mask);
}
}
#else
/* disable unused clocks */
/* disable all programmable clocks */
at91_sys_write(AT91_PMC_SCDR, AT91_PMC_PCK0 | AT91_PMC_PCK1 | AT91_PMC_PCK2 | AT91_PMC_PCK3);
#endif /* CONFIG_AT91_PROGRAMMABLE_CLOCKS */
#endif
/* 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.
*/
/* enable the PIO clocks */
clk_enable(&pioA_clk);
clk_enable(&pioB_clk);
clk_enable(&pioC_clk);
clk_enable(&pioD_clk);
/* disable all other unused peripheral clocks */
at91_periphclk_reset();
return 0;
}