[2/2] arm: omap3: am35x: Disable hlt when using Davinci EMAC

Commit Message

Mark Greer July 18, 2012, 9:32 p.m. UTC

On Tue, Jul 17, 2012 at 09:54:53PM -0600, Paul Walmsley wrote:
> Hi

Hi Paul.

> From the patch description, it doesn't sound like it's WFI entry that's 
> the problem.  The EMAC can assert its interrupt lines to the INTC, since 
> the EMAC is active.  If the MPU and CORE powerdomains are ON, then the ARM 
> core should wake up out of WFI.  (Unless there's some weird bug; always 
> possible.)
> 
> Probably the MPU DPLL has to stay running for it all to work, since I 
> think that is activated and deactivated by the PRCM.  Maybe the CORE DPLL 
> has to stay running too (but I doubt it).  But I'll bet that all the 
> clocks downstream of the DPLLs can be gated.  If it works, that would save 
> a lot of energy over the disable_hlt() approach.  With disable_hlt(), the 
> ARM & interconnect is just going to be burning power waiting for the 
> interrupt to come in.

Makes sense.

> Want to try something like this?  It's your patch but modified to not use 
> disable/enable_hlt().  If it doesn't work in your test case, maybe 
> try uncommenting that second set of deny_idle / allow_idle ...

I tested the modified patch (to get it to compile) below.
It did not work with or without the core_dpll_ck deny_idle/allow_idle
commented out.

Mark
---
 arch/arm/mach-omap2/am35xx-emac.c     |   56 ++++++++++++++++++++++++++++++---
 arch/arm/mach-omap2/am35xx-emac.h     |   13 ++++++-
 arch/arm/mach-omap2/board-am3517evm.c |    3 +-
 arch/arm/mach-omap2/board-cm-t3517.c  |    3 +-
 4 files changed, 66 insertions(+), 9 deletions(-)

Patch

diff --git a/arch/arm/mach-omap2/am35xx-emac.c b/arch/arm/mach-omap2/am35xx-emac.c
index 2c90ac6..ed695e8 100644
--- a/arch/arm/mach-omap2/am35xx-emac.c
+++ b/arch/arm/mach-omap2/am35xx-emac.c
@@ -16,13 +16,50 @@ 
  */
 
 #include <linux/err.h>
+#include <linux/clk.h>
 #include <linux/davinci_emac.h>
 #include <asm/system.h>
+#include <plat/clock.h>
 #include <plat/omap_device.h>
 #include <mach/am35xx.h>
 #include "control.h"
 #include "am35xx-emac.h"
 
+static struct clk *mpu_dpll_ck, *core_dpll_ck;
+
+/*
+ * Default pm_lats for the am35x.
+ * The net effect of using am35xx_emac_pm_lats[] is that
+ * pm_idle or CPUidle won't be called while the emac
+ * interface is open.  This is required because the
+ * EMAC can't wake up PRCM so if the MPU is executing
+ * a 'wfi' instruction (e.g., from pm_idle or CPUidle),
+ * it won't break out of it due to emac activity.
+ */
+static int am35xx_emac_deactivate_func(struct omap_device *od)
+{
+	mpu_dpll_ck->ops->deny_idle(mpu_dpll_ck);
+	/* core_dpll_ck->ops->deny_idle(core_dpll_ck); */
+	return omap_device_idle_hwmods(od);
+}
+
+static int am35xx_emac_activate_func(struct omap_device *od)
+{
+	mpu_dpll_ck->ops->allow_idle(mpu_dpll_ck);
+	/* core_dpll_ck->ops->allow_idle(core_dpll_ck); */
+	return omap_device_enable_hwmods(od);
+}
+
+struct omap_device_pm_latency am35xx_emac_pm_lats[] = {
+	{
+		.deactivate_func	= am35xx_emac_deactivate_func,
+		.activate_func		= am35xx_emac_activate_func,
+		.flags			= OMAP_DEVICE_LATENCY_AUTO_ADJUST,
+	},
+};
+
+int am35xx_emac_pm_lats_size = ARRAY_SIZE(am35xx_emac_pm_lats);
+
 static void am35xx_enable_emac_int(void)
 {
 	u32 v;
@@ -58,12 +95,14 @@  static struct emac_platform_data am35xx_emac_pdata = {
 static struct mdio_platform_data am35xx_mdio_pdata;
 
 static int __init omap_davinci_emac_dev_init(struct omap_hwmod *oh,
-		void *pdata, int pdata_len)
+					     void *pdata, int pdata_len,
+					     struct omap_device_pm_latency *pm_lats,
+					     int pm_lats_size)
 {
 	struct platform_device *pdev;
 
 	pdev = omap_device_build(oh->class->name, 0, oh, pdata, pdata_len,
-				 NULL, 0, false);
+				 pm_lats, pm_lats_size, false);
 	if (IS_ERR(pdev)) {
 		WARN(1, "Can't build omap_device for %s:%s.\n",
 		     oh->class->name, oh->name);
@@ -73,7 +112,8 @@  static int __init omap_davinci_emac_dev_init(struct omap_hwmod *oh,
 	return 0;
 }
 
-void __init am35xx_emac_init(unsigned long mdio_bus_freq, u8 rmii_en)
+void __init am35xx_emac_init(unsigned long mdio_bus_freq, u8 rmii_en,
+		struct omap_device_pm_latency *pm_lats, int pm_lats_size)
 {
 	struct omap_hwmod *oh;
 	u32 v;
@@ -88,7 +128,7 @@  void __init am35xx_emac_init(unsigned long mdio_bus_freq, u8 rmii_en)
 	am35xx_mdio_pdata.bus_freq = mdio_bus_freq;
 
 	ret = omap_davinci_emac_dev_init(oh, &am35xx_mdio_pdata,
-					 sizeof(am35xx_mdio_pdata));
+					 sizeof(am35xx_mdio_pdata), NULL, 0);
 	if (ret) {
 		pr_err("Could not build davinci_mdio hwmod device\n");
 		return;
@@ -103,12 +143,18 @@  void __init am35xx_emac_init(unsigned long mdio_bus_freq, u8 rmii_en)
 	am35xx_emac_pdata.rmii_en = rmii_en;
 
 	ret = omap_davinci_emac_dev_init(oh, &am35xx_emac_pdata,
-					 sizeof(am35xx_emac_pdata));
+					 sizeof(am35xx_emac_pdata),
+					 pm_lats, pm_lats_size);
 	if (ret) {
 		pr_err("Could not build davinci_emac hwmod device\n");
 		return;
 	}
 
+	mpu_dpll_ck = clk_get(NULL, "dpll1_ck");
+	WARN(!mpu_dpll_ck, "Can't get dpll1_ck\n");
+	core_dpll_ck = clk_get(NULL, "dpll3_ck");
+	WARN(!core_dpll_ck, "Can't get dpll3_ck\n");
+
 	v = omap_ctrl_readl(AM35XX_CONTROL_IP_SW_RESET);
 	v &= ~AM35XX_CPGMACSS_SW_RST;
 	omap_ctrl_writel(v, AM35XX_CONTROL_IP_SW_RESET);
diff --git a/arch/arm/mach-omap2/am35xx-emac.h b/arch/arm/mach-omap2/am35xx-emac.h
index 15c6f9c..446a429 100644
--- a/arch/arm/mach-omap2/am35xx-emac.h
+++ b/arch/arm/mach-omap2/am35xx-emac.h
@@ -5,11 +5,20 @@ 
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
+#include <plat/omap_device.h>
 
 #define AM35XX_DEFAULT_MDIO_FREQUENCY	1000000
 
 #if defined(CONFIG_TI_DAVINCI_EMAC) || defined(CONFIG_TI_DAVINCI_EMAC_MODULE)
-void am35xx_emac_init(unsigned long mdio_bus_freq, u8 rmii_en);
+extern struct omap_device_pm_latency am35xx_emac_pm_lats[];
+extern int am35xx_emac_pm_lats_size;
+
+void am35xx_emac_init(unsigned long mdio_bus_freq, u8 rmii_en,
+		struct omap_device_pm_latency *pm_lats, int pm_lats_size);
 #else
-static inline void am35xx_emac_init(unsigned long mdio_bus_freq, u8 rmii_en) {}
+#define am35xx_emac_pm_lats		NULL
+#define am35xx_emac_pm_lats_size	0
+
+static inline am35xx_emac_init(unsigned long mdio_bus_freq, u8 rmii_en,
+		struct omap_device_pm_latency *pm_lats, int pm_lats_size) {}
 #endif
diff --git a/arch/arm/mach-omap2/board-am3517evm.c b/arch/arm/mach-omap2/board-am3517evm.c
index 18f6010..5348d0d 100644
--- a/arch/arm/mach-omap2/board-am3517evm.c
+++ b/arch/arm/mach-omap2/board-am3517evm.c
@@ -368,7 +368,8 @@  static void __init am3517_evm_init(void)
 	i2c_register_board_info(1, am3517evm_i2c1_boardinfo,
 				ARRAY_SIZE(am3517evm_i2c1_boardinfo));
 	/*Ethernet*/
-	am35xx_emac_init(AM35XX_DEFAULT_MDIO_FREQUENCY, 1);
+	am35xx_emac_init(AM35XX_DEFAULT_MDIO_FREQUENCY, 1,
+			 am35xx_emac_pm_lats, am35xx_emac_pm_lats_size);
 
 	/* MUSB */
 	am3517_evm_musb_init();
diff --git a/arch/arm/mach-omap2/board-cm-t3517.c b/arch/arm/mach-omap2/board-cm-t3517.c
index a33ad46..8258057 100644
--- a/arch/arm/mach-omap2/board-cm-t3517.c
+++ b/arch/arm/mach-omap2/board-cm-t3517.c
@@ -292,7 +292,8 @@  static void __init cm_t3517_init(void)
 	cm_t3517_init_rtc();
 	cm_t3517_init_usbh();
 	cm_t3517_init_hecc();
-	am35xx_emac_init(AM35XX_DEFAULT_MDIO_FREQUENCY, 1);
+	am35xx_emac_init(AM35XX_DEFAULT_MDIO_FREQUENCY, 1,
+			 am35xx_emac_pm_lats, am35xx_emac_pm_lats_size);
 }
 
 MACHINE_START(CM_T3517, "Compulab CM-T3517")