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authorVaibhav Hiremath <hvaibhav@ti.com>2012-05-09 21:07:05 +0400
committerTony Lindgren <tony@atomide.com>2012-05-09 21:07:05 +0400
commit1fe97c8f6a1de67a5f56e029a818903d5bed8017 (patch)
tree850b55afd3750a58b553e04eb1c6e1f7a966c612 /arch/arm
parentf36921bebdf368ac4892f8ed62fb97dd6461d459 (diff)
downloadlinux-1fe97c8f6a1de67a5f56e029a818903d5bed8017.tar.xz
ARM: OMAP: Make OMAP clocksource source selection using kernel param
Current OMAP code supports couple of clocksource options based on compilation flag (CONFIG_OMAP_32K_TIMER). The 32KHz sync-timer and a gptimer which can run on 32KHz or system clock (e.g 38.4 MHz). So there can be 3 options - 1. 32KHz sync-timer 2. Sys_clock based (e.g 13/19.2/26/38.4 MHz) gptimer 3. 32KHz based gptimer. The optional gptimer based clocksource was added so that it can give the high precision than sync-timer, so expected usage was 2 and not 3. Unfortunately option 2, clocksource doesn't meet the requirement of free-running clock as per clocksource need. It stops in low power states when sys_clock is cut. That makes gptimer based clocksource option useless for OMAP2/3/4 devices with sys_clock as a clock input. So, in order to use option 2, deeper idle state MUST be disabled. Option 3 will still work but it is no better than 32K sync-timer based clocksource. We must support both sync timer and gptimer based clocksource as some OMAP based derivative SoCs like AM33XX does not have the sync timer. Considering above, make sync-timer and gptimer clocksource runtime selectable so that both OMAP and AMXXXX continue to use the same code. And, in order to precisely configure/setup sched_clock for given clocksource, decision has to be made early enough in boot sequence. So, the solution is, Use standard kernel parameter ("clocksource=") to override default 32k_sync-timer, in addition to this, we also use hwmod database lookup mechanism, through which at run-time we can identify availability of 32k-sync timer on the device, else fall back to gptimer. Also, moved low-level SoC specific init code to respective files, (mach-omap1/timer32k.c and mach-omap2/timer.c) Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com> Signed-off-by: Felipe Balbi <balbi@ti.com> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Acked-by: Kevin Hilman <khilman@ti.com> Tested-by: Kevin Hilman <khilman@ti.com> Cc: Benoit Cousson <b-cousson@ti.com> Cc: Paul Walmsley <paul@pwsan.com> Cc: Tarun Kanti DebBarma <tarun.kanti@ti.com> Cc: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Tony Lindgren <tony@atomide.com>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/mach-omap1/timer32k.c19
-rw-r--r--arch/arm/mach-omap2/timer.c112
-rw-r--r--arch/arm/plat-omap/counter_32k.c91
-rw-r--r--arch/arm/plat-omap/include/plat/common.h2
4 files changed, 147 insertions, 77 deletions
diff --git a/arch/arm/mach-omap1/timer32k.c b/arch/arm/mach-omap1/timer32k.c
index e3613a8bcd90..eae49c3980c9 100644
--- a/arch/arm/mach-omap1/timer32k.c
+++ b/arch/arm/mach-omap1/timer32k.c
@@ -71,6 +71,7 @@
/* 16xx specific defines */
#define OMAP1_32K_TIMER_BASE 0xfffb9000
+#define OMAP1_32KSYNC_TIMER_BASE 0xfffbc400
#define OMAP1_32K_TIMER_CR 0x08
#define OMAP1_32K_TIMER_TVR 0x00
#define OMAP1_32K_TIMER_TCR 0x04
@@ -186,8 +187,22 @@ int __init omap_32k_timer_init(void)
{
int ret = -ENODEV;
- if (cpu_is_omap16xx())
- ret = omap_init_clocksource_32k();
+ if (cpu_is_omap16xx()) {
+ void __iomem *base;
+ struct clk *sync32k_ick;
+
+ base = ioremap(OMAP1_32KSYNC_TIMER_BASE, SZ_1K);
+ if (!base) {
+ pr_err("32k_counter: failed to map base addr\n");
+ return -ENODEV;
+ }
+
+ sync32k_ick = clk_get(NULL, "omap_32ksync_ick");
+ if (!IS_ERR(sync32k_ick))
+ clk_enable(sync32k_ick);
+
+ ret = omap_init_clocksource_32k(base);
+ }
if (!ret)
omap_init_32k_timer();
diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
index 105829e403b3..840929bd9dae 100644
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -236,22 +236,8 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
}
/* Clocksource code */
-
-#ifdef CONFIG_OMAP_32K_TIMER
-/*
- * When 32k-timer is enabled, don't use GPTimer for clocksource
- * instead, just leave default clocksource which uses the 32k
- * sync counter. See clocksource setup in plat-omap/counter_32k.c
- */
-
-static void __init omap2_gp_clocksource_init(int unused, const char *dummy)
-{
- omap_init_clocksource_32k();
-}
-
-#else
-
static struct omap_dm_timer clksrc;
+static bool use_gptimer_clksrc;
/*
* clocksource
@@ -278,7 +264,46 @@ static u32 notrace dmtimer_read_sched_clock(void)
}
/* Setup free-running counter for clocksource */
-static void __init omap2_gp_clocksource_init(int gptimer_id,
+static int __init omap2_sync32k_clocksource_init(void)
+{
+ int ret;
+ struct omap_hwmod *oh;
+ void __iomem *vbase;
+ const char *oh_name = "counter_32k";
+
+ /*
+ * First check hwmod data is available for sync32k counter
+ */
+ oh = omap_hwmod_lookup(oh_name);
+ if (!oh || oh->slaves_cnt == 0)
+ return -ENODEV;
+
+ omap_hwmod_setup_one(oh_name);
+
+ vbase = omap_hwmod_get_mpu_rt_va(oh);
+ if (!vbase) {
+ pr_warn("%s: failed to get counter_32k resource\n", __func__);
+ return -ENXIO;
+ }
+
+ ret = omap_hwmod_enable(oh);
+ if (ret) {
+ pr_warn("%s: failed to enable counter_32k module (%d)\n",
+ __func__, ret);
+ return ret;
+ }
+
+ ret = omap_init_clocksource_32k(vbase);
+ if (ret) {
+ pr_warn("%s: failed to initialize counter_32k as a clocksource (%d)\n",
+ __func__, ret);
+ omap_hwmod_idle(oh);
+ }
+
+ return ret;
+}
+
+static void __init omap2_gptimer_clocksource_init(int gptimer_id,
const char *fck_source)
{
int res;
@@ -286,9 +311,6 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
res = omap_dm_timer_init_one(&clksrc, gptimer_id, fck_source);
BUG_ON(res);
- pr_info("OMAP clocksource: GPTIMER%d at %lu Hz\n",
- gptimer_id, clksrc.rate);
-
__omap_dm_timer_load_start(&clksrc,
OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR, 0, 1);
setup_sched_clock(dmtimer_read_sched_clock, 32, clksrc.rate);
@@ -296,15 +318,36 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
if (clocksource_register_hz(&clocksource_gpt, clksrc.rate))
pr_err("Could not register clocksource %s\n",
clocksource_gpt.name);
+ else
+ pr_info("OMAP clocksource: GPTIMER%d at %lu Hz\n",
+ gptimer_id, clksrc.rate);
+}
+
+static void __init omap2_clocksource_init(int gptimer_id,
+ const char *fck_source)
+{
+ /*
+ * First give preference to kernel parameter configuration
+ * by user (clocksource="gp_timer").
+ *
+ * In case of missing kernel parameter for clocksource,
+ * first check for availability for 32k-sync timer, in case
+ * of failure in finding 32k_counter module or registering
+ * it as clocksource, execution will fallback to gp-timer.
+ */
+ if (use_gptimer_clksrc == true)
+ omap2_gptimer_clocksource_init(gptimer_id, fck_source);
+ else if (omap2_sync32k_clocksource_init())
+ /* Fall back to gp-timer code */
+ omap2_gptimer_clocksource_init(gptimer_id, fck_source);
}
-#endif
#define OMAP_SYS_TIMER_INIT(name, clkev_nr, clkev_src, \
clksrc_nr, clksrc_src) \
static void __init omap##name##_timer_init(void) \
{ \
omap2_gp_clockevent_init((clkev_nr), clkev_src); \
- omap2_gp_clocksource_init((clksrc_nr), clksrc_src); \
+ omap2_clocksource_init((clksrc_nr), clksrc_src); \
}
#define OMAP_SYS_TIMER(name) \
@@ -335,7 +378,7 @@ static DEFINE_TWD_LOCAL_TIMER(twd_local_timer,
static void __init omap4_timer_init(void)
{
omap2_gp_clockevent_init(1, OMAP4_CLKEV_SOURCE);
- omap2_gp_clocksource_init(2, OMAP4_MPU_SOURCE);
+ omap2_clocksource_init(2, OMAP4_MPU_SOURCE);
#ifdef CONFIG_LOCAL_TIMERS
/* Local timers are not supprted on OMAP4430 ES1.0 */
if (omap_rev() != OMAP4430_REV_ES1_0) {
@@ -503,3 +546,28 @@ static int __init omap2_dm_timer_init(void)
return 0;
}
arch_initcall(omap2_dm_timer_init);
+
+/**
+ * omap2_override_clocksource - clocksource override with user configuration
+ *
+ * Allows user to override default clocksource, using kernel parameter
+ * clocksource="gp_timer" (For all OMAP2PLUS architectures)
+ *
+ * Note that, here we are using same standard kernel parameter "clocksource=",
+ * and not introducing any OMAP specific interface.
+ */
+static int __init omap2_override_clocksource(char *str)
+{
+ if (!str)
+ return 0;
+ /*
+ * For OMAP architecture, we only have two options
+ * - sync_32k (default)
+ * - gp_timer (sys_clk based)
+ */
+ if (!strcmp(str, "gp_timer"))
+ use_gptimer_clksrc = true;
+
+ return 0;
+}
+early_param("clocksource", omap2_override_clocksource);
diff --git a/arch/arm/plat-omap/counter_32k.c b/arch/arm/plat-omap/counter_32k.c
index 5068fe5a6910..b2f634ba7bc7 100644
--- a/arch/arm/plat-omap/counter_32k.c
+++ b/arch/arm/plat-omap/counter_32k.c
@@ -27,19 +27,20 @@
#include <plat/clock.h>
+/* OMAP2_32KSYNCNT_CR_OFF: offset of 32ksync counter register */
+#define OMAP2_32KSYNCNT_CR_OFF 0x10
+
/*
* 32KHz clocksource ... always available, on pretty most chips except
* OMAP 730 and 1510. Other timers could be used as clocksources, with
* higher resolution in free-running counter modes (e.g. 12 MHz xtal),
* but systems won't necessarily want to spend resources that way.
*/
-static void __iomem *timer_32k_base;
-
-#define OMAP16XX_TIMER_32K_SYNCHRONIZED 0xfffbc410
+static void __iomem *sync32k_cnt_reg;
static u32 notrace omap_32k_read_sched_clock(void)
{
- return timer_32k_base ? __raw_readl(timer_32k_base) : 0;
+ return sync32k_cnt_reg ? __raw_readl(sync32k_cnt_reg) : 0;
}
/**
@@ -59,7 +60,7 @@ void read_persistent_clock(struct timespec *ts)
struct timespec *tsp = &persistent_ts;
last_cycles = cycles;
- cycles = timer_32k_base ? __raw_readl(timer_32k_base) : 0;
+ cycles = sync32k_cnt_reg ? __raw_readl(sync32k_cnt_reg) : 0;
delta = cycles - last_cycles;
nsecs = clocksource_cyc2ns(delta, persistent_mult, persistent_shift);
@@ -68,54 +69,40 @@ void read_persistent_clock(struct timespec *ts)
*ts = *tsp;
}
-int __init omap_init_clocksource_32k(void)
+/**
+ * omap_init_clocksource_32k - setup and register counter 32k as a
+ * kernel clocksource
+ * @pbase: base addr of counter_32k module
+ * @size: size of counter_32k to map
+ *
+ * Returns 0 upon success or negative error code upon failure.
+ *
+ */
+int __init omap_init_clocksource_32k(void __iomem *vbase)
{
- static char err[] __initdata = KERN_ERR
- "%s: can't register clocksource!\n";
-
- if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
- u32 pbase;
- unsigned long size = SZ_4K;
- void __iomem *base;
- struct clk *sync_32k_ick;
-
- if (cpu_is_omap16xx()) {
- pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
- size = SZ_1K;
- } else if (cpu_is_omap2420())
- pbase = OMAP2420_32KSYNCT_BASE + 0x10;
- else if (cpu_is_omap2430())
- pbase = OMAP2430_32KSYNCT_BASE + 0x10;
- else if (cpu_is_omap34xx())
- pbase = OMAP3430_32KSYNCT_BASE + 0x10;
- else if (cpu_is_omap44xx())
- pbase = OMAP4430_32KSYNCT_BASE + 0x10;
- else
- return -ENODEV;
-
- /* For this to work we must have a static mapping in io.c for this area */
- base = ioremap(pbase, size);
- if (!base)
- return -ENODEV;
-
- sync_32k_ick = clk_get(NULL, "omap_32ksync_ick");
- if (!IS_ERR(sync_32k_ick))
- clk_enable(sync_32k_ick);
-
- timer_32k_base = base;
-
- /*
- * 120000 rough estimate from the calculations in
- * __clocksource_updatefreq_scale.
- */
- clocks_calc_mult_shift(&persistent_mult, &persistent_shift,
- 32768, NSEC_PER_SEC, 120000);
-
- if (clocksource_mmio_init(base, "32k_counter", 32768, 250, 32,
- clocksource_mmio_readl_up))
- printk(err, "32k_counter");
-
- setup_sched_clock(omap_32k_read_sched_clock, 32, 32768);
+ int ret;
+
+ /*
+ * 32k sync Counter register offset is at 0x10
+ */
+ sync32k_cnt_reg = vbase + OMAP2_32KSYNCNT_CR_OFF;
+
+ /*
+ * 120000 rough estimate from the calculations in
+ * __clocksource_updatefreq_scale.
+ */
+ clocks_calc_mult_shift(&persistent_mult, &persistent_shift,
+ 32768, NSEC_PER_SEC, 120000);
+
+ ret = clocksource_mmio_init(sync32k_cnt_reg, "32k_counter", 32768,
+ 250, 32, clocksource_mmio_readl_up);
+ if (ret) {
+ pr_err("32k_counter: can't register clocksource\n");
+ return ret;
}
+
+ setup_sched_clock(omap_32k_read_sched_clock, 32, 32768);
+ pr_info("OMAP clocksource: 32k_counter at 32768 Hz\n");
+
return 0;
}
diff --git a/arch/arm/plat-omap/include/plat/common.h b/arch/arm/plat-omap/include/plat/common.h
index b4d7ec3fbfbe..55c514be382e 100644
--- a/arch/arm/plat-omap/include/plat/common.h
+++ b/arch/arm/plat-omap/include/plat/common.h
@@ -30,7 +30,7 @@
#include <plat/i2c.h>
#include <plat/omap_hwmod.h>
-extern int __init omap_init_clocksource_32k(void);
+extern int __init omap_init_clocksource_32k(void __iomem *vbase);
extern void omap_reserve(void);
extern int omap_dss_reset(struct omap_hwmod *);