[PATCH 2/2] arm: omap3: am35x: Disable hlt when using Davinci EMAC
Mark A. Greer
mgreer at animalcreek.com
Wed Jul 18 17:32:46 EDT 2012
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(-)
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")
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