On Tue, May 15, 2012 at 03:42:09PM +0300, Igor Grinberg wrote:
> On 05/15/12 00:32, Kevin Hilman wrote:
> > "Mark A. Greer" <mgreer@xxxxxxxxxxxxxxx> writes:
> >
> >> On Mon, May 14, 2012 at 11:20:58AM +0300, Igor Grinberg wrote:
> >>> Hi Mark,
> >>
> >> Hi Igor.
> >>
> >>> Thanks for the great work!
> >>>
> >>> On 05/12/12 00:12, Mark A. Greer wrote:
> >>>> From: "Mark A. Greer" <mgreer@xxxxxxxxxxxxxxx>
> >>>>
> >>>> The am35x family of SoCs has a Davinci EMAC ethernet
> >>>> controller on-chip. Unfortunately, the EMAC is unable
> >>>> to wake the PRCM when there is network activity which
> >>>> leads to a hung or extremely slow system when the MPU
> >>>> has executed a 'wfi' instruction (because of pm_idle
> >>>> or CPUidle). To prevent this, add hooks to the EMAC
> >>>> pm_runtime suspend/resume calls so that hlt is disabled
> >>>> whenever the EMAC is in use.
> >>>>
> >>>> Signed-off-by: Mark A. Greer <mgreer@xxxxxxxxxxxxxxx>
> >>>> ---
> >>>> arch/arm/mach-omap2/am35xx-emac.c | 44 +++++++++++++++++++++++++++++----
> >>>> arch/arm/mach-omap2/am35xx-emac.h | 16 +++++++++---
> >>>> arch/arm/mach-omap2/board-am3517evm.c | 3 ++-
> >>>> arch/arm/mach-omap2/board-cm-t3517.c | 3 ++-
> >>>> 4 files changed, 56 insertions(+), 10 deletions(-)
> >>>>
> >>>> diff --git a/arch/arm/mach-omap2/am35xx-emac.c b/arch/arm/mach-omap2/am35xx-emac.c
> >>>> index 3bb5cb3..22ff968 100644
> >>>> --- a/arch/arm/mach-omap2/am35xx-emac.c
> >>>> +++ b/arch/arm/mach-omap2/am35xx-emac.c
> >>>> @@ -23,6 +23,37 @@
> >>>> #include "control.h"
> >>>> #include "am35xx-emac.h"
> >>>>
> >>>> +/*
> >>>> + * 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)
> >>>> +{
> >>>> + enable_hlt();
> >>>> + return omap_device_idle_hwmods(od);
> >>>> +}
> >>>> +
> >>>> +static int am35xx_emac_activate_func(struct omap_device *od)
> >>>> +{
> >>>> + disable_hlt();
> >>>> + 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 regval;
> >>>> @@ -61,12 +92,13 @@ 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);
> >>>> @@ -76,7 +108,8 @@ 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 regval;
> >>>> @@ -91,7 +124,7 @@ 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;
> >>>> @@ -106,7 +139,8 @@ 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;
> >>>> diff --git a/arch/arm/mach-omap2/am35xx-emac.h b/arch/arm/mach-omap2/am35xx-emac.h
> >>>> index 15c6f9c..7c23808 100644
> >>>> --- a/arch/arm/mach-omap2/am35xx-emac.h
> >>>> +++ b/arch/arm/mach-omap2/am35xx-emac.h
> >>>> @@ -6,10 +6,20 @@
> >>>> * 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);
> >>>> +#if IS_ENABLED(CONFIG_TI_DAVINCI_EMAC)
> >>>> +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 void 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 3645285..fe3a304 100644
> >>>> --- a/arch/arm/mach-omap2/board-am3517evm.c
> >>>> +++ b/arch/arm/mach-omap2/board-am3517evm.c
> >>>> @@ -385,7 +385,8 @@ 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);
> >>>
> >>> Why is it essential for board file to pass these pm structures?
> >>> Is it something board specific?
> >>> Can't you just use them inside the am35xx-emac.c file?
> >>
> >> Great question. I went back & forth on this mayself (I have 3 different
> >> versions sitting in my repo :). I ended up passing the pm structures in
> >> case there is a variant that comes along that doesn't need this fixup (or
> >> a board that wants to do this plus additional things).
> >>
> >> The variants that I have are:
> >>
> >> 1) Leave am35xx_emac_init() interface the way it is and automatically
> >> add the necessary things. The problem is lack of flexibility if & when
> >> some other variant comes along.
> >>
> >> 2) Add pm_lats & pm_lats_size to am35xx_emac_init() but if they're NULL
> >> or 0, then use the defaults that are the same as what's in this patch.
> >> More flexible but doesn't easily allow a board file to NULL out the pm
> >> structure (have to make up and pass NULL version).
> >>
> >> 3) Pass the pm struct via am35xx_emac_init() and just make the default
> >> available for use. This is what I submitted since it was the most flexible.
> >>
> >> Which one do you prefer or do you have something else in mind?
> >>
> >
> > For now, I suggest you stick with (1) until we have a reason to make it
> > more flexible. AFAIK, all usages of this IP in OMAP-derivative parts
> > have this same limitation.
>
> I agree with Kevin - (1) should be used.
>
> There is no need to complicate things in favor of something that might
> or might not exist some day, because even if it will exist some day,
> we probably anyway will see a better solution to this and will change
> the existing one.
Okay, I will submit v2 in a bit.
Mark
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