lkml.org 
[lkml]   [2011]   [Mar]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRE: [PATCHv3 2/3] ARM: mx51: Implement code to allow mx51 to enter WFI
Date
Hi Sascha,


>-----Original Message-----
>From: Sascha Hauer [mailto:s.hauer@pengutronix.de]
>Sent: Thursday, March 17, 2011 3:19 AM
>To: Nguyen Dinh-R00091
>Cc: linux-kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux@arm.linux.org.uk;
>u.kleine-koenig@pengutronix.de; arnaud.patard@rtp-net.org; Vaidyanathan Ranjani-RA5478; Zhang Lily-
>R58066; festevam@gmail.com
>Subject: Re: [PATCHv3 2/3] ARM: mx51: Implement code to allow mx51 to enter WFI
>
>On Wed, Mar 16, 2011 at 03:03:06PM -0500, Dinh.Nguyen@freescale.com wrote:
>> From: Dinh Nguyen <Dinh.Nguyen@freescale.com>
>>
>> Implement code for MX51 that allows the SoC to enter WFI when
>> arch_idle is called.
>>
>> This patch is also necessary for correctly suspending the system.
>>
>> Signed-off-by: Dinh Nguyen <Dinh.Nguyen@freescale.com>
>> ---
>> arch/arm/mach-mx5/Makefile | 2 +-
>> arch/arm/mach-mx5/system.c | 84 +++++++++++++++++++++++++++++++
>> arch/arm/plat-mxc/include/mach/mxc.h | 9 +++
>> arch/arm/plat-mxc/include/mach/system.h | 6 ++-
>> 4 files changed, 99 insertions(+), 2 deletions(-)
>> create mode 100644 arch/arm/mach-mx5/system.c
>>
>> diff --git a/arch/arm/mach-mx5/Makefile b/arch/arm/mach-mx5/Makefile
>> index 4f63048..0b9338c 100644
>> --- a/arch/arm/mach-mx5/Makefile
>> +++ b/arch/arm/mach-mx5/Makefile
>> @@ -3,7 +3,7 @@
>> #
>>
>> # Object file lists.
>> -obj-y := cpu.o mm.o clock-mx51-mx53.o devices.o ehci.o
>> +obj-y := cpu.o mm.o clock-mx51-mx53.o devices.o ehci.o system.o
>> obj-$(CONFIG_SOC_IMX50) += mm-mx50.o
>>
>> obj-$(CONFIG_CPU_FREQ_IMX) += cpu_op-mx51.o
>> diff --git a/arch/arm/mach-mx5/system.c b/arch/arm/mach-mx5/system.c
>> new file mode 100644
>> index 0000000..c4e9e00
>> --- /dev/null
>> +++ b/arch/arm/mach-mx5/system.c
>> @@ -0,0 +1,84 @@
>> +/*
>> + * Copyright (C) 2011 Freescale Semiconductor, Inc. All Rights Reserved.
>> + */
>> +
>> +/*
>> + * The code contained herein is licensed under the GNU General Public
>> + * License. You may obtain a copy of the GNU General Public License
>> + * Version 2 or later at the following locations:
>> + *
>> + * http://www.opensource.org/licenses/gpl-license.html
>> + * http://www.gnu.org/copyleft/gpl.html
>> + */
>> +#include <linux/platform_device.h>
>> +#include <asm/io.h>
>> +#include <mach/hardware.h>
>> +#include "crm_regs.h"
>> +
>> +/* set cpu low power mode before WFI instruction. This function is called
>> + * mx5 because it can be used for mx50, mx51, and mx53.*/
>> +void mx5_cpu_lp_set(enum mxc_cpu_pwr_mode mode)
>> +{
>> + u32 plat_lpc, arm_srpgcr, ccm_clpcr;
>> + u32 empgc0, empgc1;
>> + int stop_mode = 0;
>> +
>> + /* always allow platform to issue a deep sleep mode request */
>> + plat_lpc = __raw_readl(MXC_CORTEXA8_PLAT_LPC) &
>> + ~(MXC_CORTEXA8_PLAT_LPC_DSM);
>> + ccm_clpcr = __raw_readl(MXC_CCM_CLPCR) & ~(MXC_CCM_CLPCR_LPM_MASK);
>> + arm_srpgcr = __raw_readl(MXC_SRPG_ARM_SRPGCR) & ~(MXC_SRPGCR_PCR);
>> + empgc0 = __raw_readl(MXC_SRPG_EMPGC0_SRPGCR) & ~(MXC_SRPGCR_PCR);
>> + empgc1 = __raw_readl(MXC_SRPG_EMPGC1_SRPGCR) & ~(MXC_SRPGCR_PCR);
>
>You read empgc0/1 and mask the MXC_SRPGCR_PCR bit...
>
>> +
>> + switch (mode) {
>> + case WAIT_CLOCKED:
>> + break;
>> + case WAIT_UNCLOCKED:
>> + ccm_clpcr |= 0x1 << MXC_CCM_CLPCR_LPM_OFFSET;
>> + break;
>> + case WAIT_UNCLOCKED_POWER_OFF:
>> + case STOP_POWER_OFF:
>> + plat_lpc |= MXC_CORTEXA8_PLAT_LPC_DSM
>> + | MXC_CORTEXA8_PLAT_LPC_DBG_DSM;
>> + if (mode == WAIT_UNCLOCKED_POWER_OFF) {
>> + ccm_clpcr |= 0x1 << MXC_CCM_CLPCR_LPM_OFFSET;
>> + ccm_clpcr &= ~MXC_CCM_CLPCR_VSTBY;
>> + ccm_clpcr &= ~MXC_CCM_CLPCR_SBYOS;
>> + stop_mode = 0;
>> + } else {
>> + ccm_clpcr |= 0x2 << MXC_CCM_CLPCR_LPM_OFFSET;
>> + ccm_clpcr |= 0x3 << MXC_CCM_CLPCR_STBY_COUNT_OFFSET;
>> + ccm_clpcr |= MXC_CCM_CLPCR_VSTBY;
>> + ccm_clpcr |= MXC_CCM_CLPCR_SBYOS;
>> + stop_mode = 1;
>> + }
>> +
>> + arm_srpgcr |= MXC_SRPGCR_PCR;
>> + if (stop_mode) {
>> + empgc0 |= MXC_SRPGCR_PCR;
>> + empgc1 |= MXC_SRPGCR_PCR;
>
>... Then in stop_mode you set the bit ...
>
>> + }
>> +
>> + if (tzic_enable_wake(1) != 0)
>> + return;
>> + break;
>> + case STOP_POWER_ON:
>> + ccm_clpcr |= 0x2 << MXC_CCM_CLPCR_LPM_OFFSET;
>> + break;
>> + default:
>> + printk(KERN_WARNING "UNKNOWN cpu power mode: %d\n", mode);
>> + return;
>> + }
>> +
>> + __raw_writel(plat_lpc, MXC_CORTEXA8_PLAT_LPC);
>> + __raw_writel(ccm_clpcr, MXC_CCM_CLPCR);
>> + __raw_writel(arm_srpgcr, MXC_SRPG_ARM_SRPGCR);
>> + /* Enable NEON SRPG for all but MX50TO1.0. */
>> + __raw_writel(arm_srpgcr, MXC_SRPG_NEON_SRPGCR);
>> + if (stop_mode) {
>> + __raw_writel(empgc0, MXC_SRPG_EMPGC0_SRPGCR);
>> + __raw_writel(empgc1, MXC_SRPG_EMPGC1_SRPGCR);
>
>... and only in stop mode you write the value back. Can't we do the
>empgc0 handling here completely to make the code more clean?
>
>Also, I'm missing the implementation of 'all but MX50TO1.0'.
>
>> + }
>> +}
>> +
>> diff --git a/arch/arm/plat-mxc/include/mach/mxc.h b/arch/arm/plat-mxc/include/mach/mxc.h
>> index 7e07263..6c2a371 100644
>> --- a/arch/arm/plat-mxc/include/mach/mxc.h
>> +++ b/arch/arm/plat-mxc/include/mach/mxc.h
>> @@ -181,6 +181,15 @@ struct cpu_op {
>> u32 cpu_rate;
>> };
>>
>> +int tzic_enable_wake(int is_idle);
>> +enum mxc_cpu_pwr_mode {
>> + WAIT_CLOCKED, /* wfi only */
>> + WAIT_UNCLOCKED, /* WAIT */
>> + WAIT_UNCLOCKED_POWER_OFF, /* WAIT + SRPG */
>> + STOP_POWER_ON, /* just STOP */
>> + STOP_POWER_OFF, /* STOP + SRPG */
>> +};
>> +
>> extern struct cpu_op *(*get_cpu_op)(int *op);
>> #endif
>>
>> diff --git a/arch/arm/plat-mxc/include/mach/system.h b/arch/arm/plat-mxc/include/mach/system.h
>> index 95be51b..0417da9 100644
>> --- a/arch/arm/plat-mxc/include/mach/system.h
>> +++ b/arch/arm/plat-mxc/include/mach/system.h
>> @@ -20,6 +20,8 @@
>> #include <mach/hardware.h>
>> #include <mach/common.h>
>>
>> +extern void mx5_cpu_lp_set(enum mxc_cpu_pwr_mode mode);
>> +
>> static inline void arch_idle(void)
>> {
>> #ifdef CONFIG_ARCH_MXC91231
>> @@ -54,7 +56,9 @@ static inline void arch_idle(void)
>> "orr %0, %0, #0x00000004\n"
>> "mcr p15, 0, %0, c1, c0, 0\n"
>> : "=r" (reg));
>> - } else
>> + } else if (cpu_is_mx51())
>> + mx5_cpu_lp_set(WAIT_UNCLOCKED_POWER_OFF);
>> + else
>
>Have you tried compiling this on !i.MX5 systems?

Yes, I have and its build fine for mx3_defconfig. I did find a build issue with mx27_defconfig, but it's not related to this patch:

In file included from arch/arm/mm/init.c:27:
/arm/include/asm/tlb.h: In function 'tlb_flush_mmu':
arch/arm/include/asm/tlb.h:104: error: implicit declaration of function 'release_pages'
arch/arm/include/asm/tlb.h: In function 'tlb_remove_page':
arch/arm/include/asm/tlb.h:168: error: implicit declaration of function 'page_cache_release'
make[1]: *** [arch/arm/mm/init.o] Error 1
make: *** [arch/arm/mm] Error 2

Thanks for the review, v4 is on its way.

Dinh
>
>Sascha
>
>--
>Pengutronix e.K. | |
>Industrial Linux Solutions | http://www.pengutronix.de/ |
>Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
>Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |




\
 
 \ /
  Last update: 2011-03-17 17:55    [from the cache]
©2003-2011 Jasper Spaans