[RFC PATCH] AT91: manage clock by functionality instead of CPUs
From: Nicolas Ferre
Date: Fri Mar 20 2009 - 07:04:51 EST
In clock.c file the clock management is grouped by cpu
with cpu_is_xxx() function. This lead to some kind of
difficulties to read this file and maintainability issues
as the number of AT91 cpus & PLLs/clocks is growing.
In this patch, I try to group clock functionality
together and match cpus with this functionality set.
This patch is a preview extracted from our 2.6.27-exp
patch available at linux4sam.org (applies on top of Andrew's one).
I would like to have some feedback from you about this
before I rebase it on current kernel for submission.
Signed-off-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>
--- a/arch/arm/mach-at91/clock.c
+++ b/arch/arm/mach-at91/clock.c
@@ -45,6 +45,25 @@
#define clk_is_sys(x) ((x)->type & CLK_TYPE_SYSTEM)
+/*
+ * Chips have some kind of clocks : group them by functionality
+ */
+#define cpu_has_utmi() ( cpu_is_at91cap9() \
+ || cpu_is_at91sam9rl())
+
+#define cpu_has_800M_plla() (cpu_is_at91sam9g20())
+
+#define cpu_has_pllb() (!(cpu_is_at91sam9rl()))
+
+#define cpu_has_upll() (0)
+
+/* USB host HS & FS */
+#define cpu_has_uhp() (!cpu_is_at91sam9rl())
+
+/* USB device FS only */
+#define cpu_has_udpfs() (!(cpu_is_at91sam9rl()))
+
+
static LIST_HEAD(clocks);
static DEFINE_SPINLOCK(clk_lock);
@@ -142,7 +161,7 @@ static struct clk utmi_clk = {
};
static struct clk uhpck = {
.name = "uhpck",
- .parent = &pllb,
+ /*.parent = ... we choose parent at runtime */
.mode = pmc_sys_mode,
};
@@ -175,7 +194,12 @@ static struct clk __init *at91_css_to_cl
case AT91_PMC_CSS_PLLA:
return &plla;
case AT91_PMC_CSS_PLLB:
- return &pllb;
+ if (cpu_has_upll())
+ /* CSS_PLLB == CSS_UPLL */
+ return &utmi_clk;
+ else
+ if (cpu_has_pllb())
+ return &pllb;
}
return NULL;
@@ -341,7 +365,7 @@ int clk_set_rate(struct clk *clk, unsign
u32 pckr;
pckr = at91_sys_read(AT91_PMC_PCKR(clk->id));
- pckr &= AT91_PMC_CSS_PLLB; /* clock selection */
+ pckr &= AT91_PMC_CSS; /* clock selection */
pckr |= prescale << 2;
at91_sys_write(AT91_PMC_PCKR(clk->id), pckr);
clk->rate_hz = actual;
@@ -369,6 +393,10 @@ int clk_set_parent(struct clk *clk, stru
return -EBUSY;
if (!clk_is_primary(parent) || !clk_is_programmable(clk))
return -EINVAL;
+
+ if (cpu_is_at91sam9rl() && parent->id == AT91_PMC_CSS_PLLB)
+ return -EINVAL;
+
spin_lock_irqsave(&clk_lock, flags);
clk->rate_hz = parent->rate_hz;
@@ -380,7 +408,7 @@ int clk_set_parent(struct clk *clk, stru
}
EXPORT_SYMBOL(clk_set_parent);
-/* establish PCK0..PCK3 parentage and rate */
+/* establish PCK0..PCKN parentage and rate */
static void __init init_programmable_clock(struct clk *clk)
{
struct clk *parent;
@@ -408,11 +436,13 @@ static int at91_clk_show(struct seq_file
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));
- if (!cpu_is_at91sam9rl())
+ if (cpu_has_pllb())
seq_printf(s, "PLLB = %8x\n", at91_sys_read(AT91_CKGR_PLLBR));
- if (cpu_is_at91cap9() || cpu_is_at91sam9rl())
+ if (cpu_has_utmi())
seq_printf(s, "UCKR = %8x\n", uckr = at91_sys_read(AT91_CKGR_UCKR));
seq_printf(s, "MCKR = %8x\n", at91_sys_read(AT91_PMC_MCKR));
+ if (cpu_has_upll())
+ seq_printf(s, "USB = %8x\n", at91_sys_read(AT91_PMC_USB));
seq_printf(s, "SR = %8x\n", sr = at91_sys_read(AT91_PMC_SR));
seq_printf(s, "\n");
@@ -573,16 +603,60 @@ static struct clk *const standard_pmc_cl
&clk32k,
&main_clk,
&plla,
- &pllb,
-
- /* PLLB children (USB) */
- &udpck,
- &uhpck,
/* MCK */
&mck
};
+/* PLLB generated USB full speed clock init */
+static void __init at91_pllb_usbfs_clock_init(unsigned long main_clock)
+{
+ /*
+ * USB clock init: choose 48 MHz PLLB value,
+ * disable 48MHz clock during usb peripheral suspend.
+ *
+ * REVISIT: assumes MCK doesn't derive from PLLB!
+ */
+ uhpck.parent = &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() || cpu_is_at91sam9g20()) {
+ uhpck.pmc_mask = AT91SAM926x_PMC_UHP;
+ udpck.pmc_mask = AT91SAM926x_PMC_UDP;
+ } else if (cpu_is_at91cap9()) {
+ uhpck.pmc_mask = AT91CAP9_PMC_UHP;
+ }
+ 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);
+}
+
+/* UPLL generated USB full speed clock init */
+static void __init at91_upll_usbfs_clock_init(unsigned long main_clock)
+{
+ /*
+ * USB clock init: choose 480 MHz from UPLL,
+ */
+ unsigned int usbr = AT91_PMC_USBS_UPLL;
+
+ /* Setup divider by 10 to reach 48 MHz */
+ usbr |= ((10 - 1) << 8) & AT91_PMC_OHCIUSBDIV;
+
+ at91_sys_write(AT91_PMC_USB, usbr);
+
+ /* Now set uhpck values */
+ uhpck.parent = &utmi_clk;
+ uhpck.pmc_mask = AT91SAM926x_PMC_UHP;
+ uhpck.rate_hz = utmi_clk.parent->rate_hz;
+ uhpck.rate_hz /= 1 + ((at91_sys_read(AT91_PMC_USB) & AT91_PMC_OHCIUSBDIV) >> 8);
+}
+
int __init at91_clock_init(unsigned long main_clock)
{
unsigned tmp, freq, mckr;
@@ -604,43 +678,37 @@ int __init at91_clock_init(unsigned long
/* report if PLLA is more than mildly overclocked */
plla.rate_hz = at91_pll_rate(&plla, main_clock, at91_sys_read(AT91_CKGR_PLLAR));
- if ((!cpu_is_at91sam9g20() && plla.rate_hz > 209000000)
- || (cpu_is_at91sam9g20() && plla.rate_hz > 800000000))
+ if ((!cpu_has_800M_plla() && plla.rate_hz > 209000000)
+ || (cpu_has_800M_plla() && plla.rate_hz > 800000000))
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() || cpu_is_at91sam9g20()) {
- uhpck.pmc_mask = AT91SAM926x_PMC_UHP;
- udpck.pmc_mask = AT91SAM926x_PMC_UDP;
- } else if (cpu_is_at91cap9()) {
- uhpck.pmc_mask = AT91CAP9_PMC_UHP;
+
+ if (!cpu_has_pllb() && cpu_has_upll()) {
+ /* setup UTMI clock as the fourth primary clock
+ * (instead of pllb) */
+ utmi_clk.type |= CLK_TYPE_PRIMARY;
+ utmi_clk.id = 3;
}
- 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);
/*
* USB HS clock init
*/
- if (cpu_is_at91cap9() || cpu_is_at91sam9rl()) {
+ if (cpu_has_utmi())
/*
* multiplier is hard-wired to 40
* (obtain the USB High Speed 480 MHz when input is 12 MHz)
*/
utmi_clk.rate_hz = 40 * utmi_clk.parent->rate_hz;
- }
+
+ /*
+ * USB FS clock init
+ */
+ if (cpu_has_pllb())
+ at91_pllb_usbfs_clock_init(main_clock);
+ if (cpu_has_upll())
+ /* assumes that we choose UPLL for USB and not PLLA */
+ at91_upll_usbfs_clock_init(main_clock);
/*
* MCK and CPU derive from one of those primary clocks.
@@ -650,21 +718,31 @@ int __init at91_clock_init(unsigned long
mck.parent = at91_css_to_clk(mckr & AT91_PMC_CSS);
freq = mck.parent->rate_hz;
freq /= (1 << ((mckr & AT91_PMC_PRES) >> 2)); /* prescale */
- if (cpu_is_at91rm9200())
+ if (cpu_is_at91rm9200()) {
mck.rate_hz = freq / (1 + ((mckr & AT91_PMC_MDIV) >> 8)); /* mdiv */
- else if (cpu_is_at91sam9g20()) {
+ } else if (cpu_is_at91sam9g20()) {
mck.rate_hz = (mckr & AT91_PMC_MDIV) ?
freq / ((mckr & AT91_PMC_MDIV) >> 7) : freq; /* mdiv ; (x >> 7) = ((x >> 8) * 2) */
if (mckr & AT91_PMC_PDIV)
freq /= 2; /* processor clock division */
- } else
- mck.rate_hz = freq / (1 << ((mckr & AT91_PMC_MDIV) >> 8)); /* mdiv */
+ } else {
+ mck.rate_hz = freq / (1 << ((mckr & AT91_PMC_MDIV) >> 8)); /* 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);
- if (cpu_is_at91cap9() || cpu_is_at91sam9rl())
+ if (cpu_has_pllb())
+ list_add_tail(&pllb.node, &clocks);
+
+ if (cpu_has_uhp())
+ list_add_tail(&uhpck.node, &clocks);
+
+ if (cpu_has_udpfs())
+ list_add_tail(&udpck.node, &clocks);
+
+ if (cpu_has_utmi())
list_add_tail(&utmi_clk.node, &clocks);
/* MCK and CPU clock are "always on" */
--
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