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imx: gpt: Add High frequency clock source support for GPT

PATCH Superseded Ye.Li 2 participants 6 messages Oct 28, 2014 – Oct 30, 2014

Subsystems (2)
Arm (32-bit) Arm i.MX and Layerscape

v2 of 3 Superseded Latest is v3 →

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Ye.Li

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#0 lore raw

PATCH v2 1/5 imx: gpt: Add High frequency clock source support for GPT

Introduce a new configuration "CONFIG_MXC_GPT_HCLK". When it is set, the GPT will select a high frequency clock as clock source. Otherwise, the GPT will stay to use 32Khz OSC as clock source.

In the implementation, since only the GPT on i.MX6 series provide the clock source option for 24Mhz OSC. For others (only i.MX5 and i.MX6 compile the driver), if the configuration is set, the perclk will be selected as clock source.
MX6Q/D Rev 1.0 and MX6SL are special in the implementation, because they don't have the 24Mhz OSC clock source option, so also select the perclk for them. For MX6SL, we will set the OSC 24Mhz to perclk in CCM, so eventually the clock comes from OSC 24Mhz.

Signed-off-by Ye.Li <[email protected]>

---
Changes since v1:
- Modify the patch message content to clear the implementation.
- Remove the change for copyright date.

 arch/arm/imx-common/timer.c |   74 +++++++++++++++++++++++++++++++++++++-----
 1 files changed, 65 insertions(+), 9 deletions(-)
arch/arm/imx-common/timer.c +65 -9
index c63f78f..aec0566 100644
@@ -12,6 +12,7 @@
 #include <div64.h>
 #include <asm/arch/imx-regs.h>
 #include <asm/arch/clock.h>
+#include <asm/arch/sys_proto.h>
 
 /* General purpose timers registers */
 struct mxc_gpt {

@@ -26,23 +27,60 @@ static struct mxc_gpt *cur_gpt = (struct mxc_gpt *)GPT1_BASE_ADDR;
 
 /* General purpose timers bitfields */
 #define GPTCR_SWR		(1 << 15)	/* Software reset */
+#define GPTCR_24MEN	    (1 << 10)	/* Enable 24MHz clock input from crystal */
 #define GPTCR_FRR		(1 << 9)	/* Freerun / restart */
-#define GPTCR_CLKSOURCE_32	(4 << 6)	/* Clock source */
+#define GPTCR_CLKSOURCE_32	(4 << 6)	/* Clock source 32khz */
+#define GPTCR_CLKSOURCE_OSC	(5 << 6)	/* Clock source OSC */
+#define GPTCR_CLKSOURCE_PRE	(1 << 6)	/* Clock source PRECLK */
+#define GPTCR_CLKSOURCE_MASK (0x7 << 6)
 #define GPTCR_TEN		1		/* Timer enable */
 
+#define GPTPR_PRESCALER24M_SHIFT 12
+#define GPTPR_PRESCALER24M_MASK (0xF << GPTPR_PRESCALER24M_SHIFT)
+
 DECLARE_GLOBAL_DATA_PTR;
 
+static inline int gpt_has_clk_source_osc(void)
+{
+#if defined(CONFIG_MX6)
+	if (((is_cpu_type(MXC_CPU_MX6Q) || is_cpu_type(MXC_CPU_MX6D))
+		&& (is_soc_rev(CHIP_REV_1_0) > 0))
+		|| is_cpu_type(MXC_CPU_MX6DL) || is_cpu_type(MXC_CPU_MX6SOLO)
+		|| is_cpu_type(MXC_CPU_MX6SX))
+		return 1;
+
+	return 0;
+#else
+	return 0;
+#endif
+}
+
+static inline ulong gpt_get_clk(void)
+{
+#ifdef CONFIG_MXC_GPT_HCLK
+	if (gpt_has_clk_source_osc())
+		return MXC_HCLK >> 3;
+	else
+		return mxc_get_clock(MXC_IPG_PERCLK);
+#else
+	return MXC_CLK32;
+#endif
+}
 static inline unsigned long long tick_to_time(unsigned long long tick)
 {
+	ulong gpt_clk = gpt_get_clk();
+
 	tick *= CONFIG_SYS_HZ;
-	do_div(tick, MXC_CLK32);
+	do_div(tick, gpt_clk);
 
 	return tick;
 }
 
 static inline unsigned long long us_to_tick(unsigned long long usec)
 {
-	usec = usec * MXC_CLK32 + 999999;
+	ulong gpt_clk = gpt_get_clk();
+
+	usec = usec * gpt_clk + 999999;
 	do_div(usec, 1000000);
 
 	return usec;

@@ -59,11 +97,29 @@ int timer_init(void)
 	for (i = 0; i < 100; i++)
 		__raw_writel(0, &cur_gpt->control);
 
-	__raw_writel(0, &cur_gpt->prescaler); /* 32Khz */
-
-	/* Freerun Mode, PERCLK1 input */
 	i = __raw_readl(&cur_gpt->control);
-	__raw_writel(i | GPTCR_CLKSOURCE_32 | GPTCR_TEN, &cur_gpt->control);
+	i &= ~GPTCR_CLKSOURCE_MASK;
+
+#ifdef CONFIG_MXC_GPT_HCLK
+	if (gpt_has_clk_source_osc()) {
+		i |= GPTCR_CLKSOURCE_OSC | GPTCR_TEN;
+
+		/* For DL/S, SX, they has 24M OSC Enable bit and need to set prescaler */
+		if (is_cpu_type(MXC_CPU_MX6DL) || is_cpu_type(MXC_CPU_MX6SOLO)
+			|| is_cpu_type(MXC_CPU_MX6SX)) {
+			i |= GPTCR_24MEN;
+
+			/* Produce 3Mhz clock */
+			__raw_writel((7 << GPTPR_PRESCALER24M_SHIFT), &cur_gpt->prescaler);
+		}
+	} else {
+		i |= GPTCR_CLKSOURCE_PRE | GPTCR_TEN;
+	}
+#else
+	__raw_writel(0, &cur_gpt->prescaler); /* 32Khz */
+	i |= GPTCR_CLKSOURCE_32 | GPTCR_TEN;
+#endif
+	__raw_writel(i, &cur_gpt->control);
 
 	gd->arch.tbl = __raw_readl(&cur_gpt->counter);
 	gd->arch.tbu = 0;

@@ -86,7 +142,7 @@ ulong get_timer_masked(void)
 {
 	/*
 	 * get_ticks() returns a long long (64 bit), it wraps in
-	 * 2^64 / MXC_CLK32 = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~
+	 * 2^64 / GPT_CLK = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~
 	 * 5 * 10^9 days... and get_ticks() * CONFIG_SYS_HZ wraps in
 	 * 5 * 10^6 days - long enough.
 	 */

@@ -117,5 +173,5 @@ void __udelay(unsigned long usec)
  */
 ulong get_tbclk(void)
 {
-	return MXC_CLK32;
+	return gpt_get_clk();
 }
Signature · 1 line
1.7.4.1
author
#1 lore raw

PATCH v2 2/5 imx: mx6sl: Add perclk_clk_sel bit define in CCM

The MX6SL has the perclk_clk_sel to select the perclk source. Add its define in CCM

Signed-off-by Ye.Li <[email protected]>

---
Changes since v1:
- None

 arch/arm/include/asm/arch-mx6/crm_regs.h |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
arch/arm/include/asm/arch-mx6/crm_regs.h +2 -0
index e67b5b9..53ffb3d 100644
@@ -228,6 +228,8 @@ struct mxc_ccm_reg {
 #ifdef CONFIG_MX6SX
 #define MXC_CCM_CSCMR1_QSPI1_CLK_SEL_MASK		(0x7 << 7)
 #define MXC_CCM_CSCMR1_QSPI1_CLK_SEL_OFFSET		7
+#endif
+#if (defined(CONFIG_MX6SL) || defined(CONFIG_MX6SX))
 #define MXC_CCM_CSCMR1_PER_CLK_SEL_MASK			(1 << 6)
 #define MXC_CCM_CSCMR1_PER_CLK_SEL_OFFSET		6
 #endif
Signature · 1 line
1.7.4.1
author
#2 lore raw

PATCH v2 3/5 imx: mx6: Change the get_ipg_per_clk for OSC 24Mhz source

In reply to Ye.Li

For MX6SL and MX6SX, the perclk can come from OSC 24Mhz source. Fix the get_ipg_per_clk function to support it.

Signed-off-by Ye.Li <[email protected]>

---
Changes since v1:
- None

 arch/arm/cpu/armv7/mx6/clock.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
arch/arm/cpu/armv7/mx6/clock.c +4 -0
index d200531..6c9c78c 100644
@@ -312,6 +312,10 @@ static u32 get_ipg_per_clk(void)
 	u32 reg, perclk_podf;
 
 	reg = __raw_readl(&imx_ccm->cscmr1);
+#if (defined(CONFIG_MX6SL) || defined(CONFIG_MX6SX))
+	if (reg & MXC_CCM_CSCMR1_PER_CLK_SEL_MASK)
+		return MXC_HCLK; /* OSC 24Mhz */
+#endif
 	perclk_podf = reg & MXC_CCM_CSCMR1_PERCLK_PODF_MASK;
 
 	return get_ipg_clk() / (perclk_podf + 1);
Signature · 1 line
1.7.4.1
author
#3 lore raw

PATCH v2 4/5 imx: mx6sl: Set the preclk clock source to OSC 24Mhz

In reply to Ye.Li

For MX6SL, uses the OSC 24Mhz as the preclk source in CCM. Align the preclk setting with kernel.

Signed-off-by Ye.Li <[email protected]>

---
Changes since v1:
- None

 arch/arm/cpu/armv7/mx6/soc.c |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)
arch/arm/cpu/armv7/mx6/soc.c +17 -0
index 6dc2600..c0bb431 100644
@@ -239,6 +239,18 @@ static void clear_mmdc_ch_mask(void)
 	writel(0, &mxc_ccm->ccdr);
 }
 
+#ifdef CONFIG_MX6SL
+static void set_preclk_from_osc(void)
+{
+	struct mxc_ccm_reg *mxc_ccm = (struct mxc_ccm_reg *)CCM_BASE_ADDR;
+	u32 reg;
+
+	reg = readl(&mxc_ccm->cscmr1);
+	reg |= MXC_CCM_CSCMR1_PER_CLK_SEL_MASK;
+	writel(reg, &mxc_ccm->cscmr1);
+}
+#endif
+
 int arch_cpu_init(void)
 {
 	init_aips();

@@ -254,6 +266,11 @@ int arch_cpu_init(void)
 	if (mxc_get_clock(MXC_ARM_CLK) == 396000000)
 		set_ahb_rate(132000000);
 
+		/* Set perclk to source from OSC 24MHz */
+#if defined(CONFIG_MX6SL)
+	set_preclk_from_osc();
+#endif
+
 	imx_set_wdog_powerdown(false); /* Disable PDE bit of WMCR register */
 
 #ifdef CONFIG_APBH_DMA
Signature · 1 line
1.7.4.1
author
#4 lore raw

PATCH v2 5/5 imx: mx6: Enable high frequency clock source for GPT

In reply to Ye.Li

Set the CONFIG_MXC_GPT_HCLK configuration in mx6_common.h, so that 24Mhz OSC clock source will be selected for GPT on all MX6 platforms.

Signed-off-by Ye.Li <[email protected]>

---
Changes since v1:
- Modify the patch message subject and content to use high frequency clock.

 include/configs/mx6_common.h |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
include/configs/mx6_common.h +1 -0
index 135a3f5..e0528ce 100644
@@ -29,5 +29,6 @@
 #endif
 
 #define CONFIG_MP
+#define CONFIG_MXC_GPT_HCLK
 
 #endif
Signature · 1 line
1.7.4.1
#5 lore raw

PATCH v2 1/5 imx: gpt: Add High frequency clock source support for GPT

In reply to Ye.Li

Hi Ye,

Quoted 13 lines · Ye.Li

Introduce a new configuration "CONFIG_MXC_GPT_HCLK". When it is set, the GPT will select a high frequency clock as clock source. Otherwise, the GPT will stay to use 32Khz OSC as clock source.

In the implementation, since only the GPT on i.MX6 series provide the clock source option for 24Mhz OSC. For others (only i.MX5 and i.MX6 compile the driver), if the configuration is set, the perclk will be selected as clock source.
MX6Q/D Rev 1.0 and MX6SL are special in the implementation, because they don't have the 24Mhz OSC clock source option, so also select the perclk for them. For MX6SL, we will set the OSC 24Mhz to perclk in CCM, so eventually the clock comes from OSC 24Mhz.

Quoted 2 lines
Signed-off-by Ye.Li <[email protected]>

---

There are some checkpatch warnings ("line over 80 chars"). Can you fix them and repost ? - Thanks !

Best regards,
Stefano Babic

Signature · 5 lines
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