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mfd: dbx500: Provide a more accurate smp_twd clock 

The local timer clock is based on ARM subsystem clock. This patch
obtains a more exact value of that clock by reading PRCMU registers.
Using this increases the accuracy of the local timer events.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rickard Andersson <rickard.andersson@stericsson.com>
Signed-off-by: Michel Jaouen <michel.jaouen@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This commit is contained in:
Michel Jaouen 2012-08-31 14:21:30 +02:00 committed by Samuel Ortiz
parent 0dd96360e2
commit 804971ec37
3 changed files with 45 additions and 1 deletions
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41
drivers/mfd/db8500-prcmu.c
View File

@ -418,6 +418,9 @@ static struct {
static atomic_t ac_wake_req_state = ATOMIC_INIT(0);
/* Functions definition */
static void compute_armss_rate(void);
/* Spinlocks */
static DEFINE_SPINLOCK(prcmu_lock);
static DEFINE_SPINLOCK(clkout_lock);
@ -1013,6 +1016,7 @@ int db8500_prcmu_set_arm_opp(u8 opp)
(mb1_transfer.ack.arm_opp != opp))
r = -EIO;
compute_armss_rate();
mutex_unlock(&mb1_transfer.lock);
return r;
@ -1612,6 +1616,7 @@ static unsigned long pll_rate(void __iomem *reg, unsigned long src_rate,
if ((branch == PLL_FIX) || ((branch == PLL_DIV) &&
(val & PRCM_PLL_FREQ_DIV2EN) &&
((reg == PRCM_PLLSOC0_FREQ) ||
(reg == PRCM_PLLARM_FREQ) ||
(reg == PRCM_PLLDDR_FREQ))))
div *= 2;
@ -1661,6 +1666,39 @@ static unsigned long clock_rate(u8 clock)
else
return 0;
}
static unsigned long latest_armss_rate;
static unsigned long armss_rate(void)
{
return latest_armss_rate;
}
static void compute_armss_rate(void)
{
u32 r;
unsigned long rate;
r = readl(PRCM_ARM_CHGCLKREQ);
if (r & PRCM_ARM_CHGCLKREQ_PRCM_ARM_CHGCLKREQ) {
/* External ARMCLKFIX clock */
rate = pll_rate(PRCM_PLLDDR_FREQ, ROOT_CLOCK_RATE, PLL_FIX);
/* Check PRCM_ARM_CHGCLKREQ divider */
if (!(r & PRCM_ARM_CHGCLKREQ_PRCM_ARM_DIVSEL))
rate /= 2;
/* Check PRCM_ARMCLKFIX_MGT divider */
r = readl(PRCM_ARMCLKFIX_MGT);
r &= PRCM_CLK_MGT_CLKPLLDIV_MASK;
rate /= r;
} else {/* ARM PLL */
rate = pll_rate(PRCM_PLLARM_FREQ, ROOT_CLOCK_RATE, PLL_DIV);
}
latest_armss_rate = rate;
}
static unsigned long dsiclk_rate(u8 n)
{
@ -1707,6 +1745,8 @@ unsigned long prcmu_clock_rate(u8 clock)
return pll_rate(PRCM_PLLSOC0_FREQ, ROOT_CLOCK_RATE, PLL_RAW);
else if (clock == PRCMU_PLLSOC1)
return pll_rate(PRCM_PLLSOC1_FREQ, ROOT_CLOCK_RATE, PLL_RAW);
else if (clock == PRCMU_ARMSS)
return armss_rate();
else if (clock == PRCMU_PLLDDR)
return pll_rate(PRCM_PLLDDR_FREQ, ROOT_CLOCK_RATE, PLL_RAW);
else if (clock == PRCMU_PLLDSI)
@ -2693,6 +2733,7 @@ void __init db8500_prcmu_early_init(void)
handle_simple_irq);
set_irq_flags(irq, IRQF_VALID);
}
compute_armss_rate();
}
static void __init init_prcm_registers(void)

4
drivers/mfd/dbx500-prcmu-regs.h
View File

@ -61,7 +61,8 @@
#define PRCM_PLLARM_LOCKP_PRCM_PLLARM_LOCKP3 0x2
#define PRCM_ARM_CHGCLKREQ (_PRCMU_BASE + 0x114)
#define PRCM_ARM_CHGCLKREQ_PRCM_ARM_CHGCLKREQ 0x1
#define PRCM_ARM_CHGCLKREQ_PRCM_ARM_CHGCLKREQ BIT(0)
#define PRCM_ARM_CHGCLKREQ_PRCM_ARM_DIVSEL BIT(16)
#define PRCM_PLLARM_ENABLE (_PRCMU_BASE + 0x98)
#define PRCM_PLLARM_ENABLE_PRCM_PLLARM_ENABLE 0x1
@ -140,6 +141,7 @@
/* PRCMU clock/PLL/reset registers */
#define PRCM_PLLSOC0_FREQ (_PRCMU_BASE + 0x080)
#define PRCM_PLLSOC1_FREQ (_PRCMU_BASE + 0x084)
#define PRCM_PLLARM_FREQ (_PRCMU_BASE + 0x088)
#define PRCM_PLLDDR_FREQ (_PRCMU_BASE + 0x08C)
#define PRCM_PLL_FREQ_D_SHIFT 0
#define PRCM_PLL_FREQ_D_MASK BITS(0, 7)

1
include/linux/mfd/dbx500-prcmu.h
View File

@ -136,6 +136,7 @@ enum prcmu_clock {
PRCMU_TIMCLK,
PRCMU_PLLSOC0,
PRCMU_PLLSOC1,
PRCMU_ARMSS,
PRCMU_PLLDDR,
PRCMU_PLLDSI,
PRCMU_DSI0CLK,