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From: khilman@ti•com (Kevin Hilman)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCHv2 06/19] ARM: OMAP4: PM: Add SAR backup support towards device OFF
Date: Wed, 16 May 2012 15:58:28 -0700	[thread overview]
Message-ID: <87aa177my3.fsf@ti.com> (raw)
In-Reply-To: <1336990730-26892-7-git-send-email-t-kristo@ti.com> (Tero Kristo's message of "Mon, 14 May 2012 13:18:37 +0300")

Tero Kristo <t-kristo@ti•com> writes:

> From: Santosh Shilimkar <santosh.shilimkar@ti•com>
>
> The SAR RAM is maintained during Device OFF mode. 

so why is this patch bothering to save and restore it?

-ECONFUSED

> The register layout
> is fixed in SAR ROM. SAR is split into 4 banks with different
> privilege accesses based on device type
>
>  ---------------------------------------------------------------
>  Access mode		Bank	Address Range
>  ---------------------------------------------------------------
>  HS/GP : Public		1	0x4A32_6000 - 0x4A32_6FFF (4kB)
>  HS/GP : Public		2	0x4A32_7000 - 0x4A32_73FF (1kB)
>
>  HS/EMU : Secured
>  GP : Public		3	0x4A32_8000 - 0x4A32_87FF (2kB)
>
>  HS/GP :Secure
>  write once.		4	0x4A32_9000 - 0x4A32_93FF (1kB)
>  ---------------------------------------------------------------
>
> The save process is done entirely by software and restore is done by
> hardware using the auto-restore feature. The restore feature is enabled
> by default and cannot be disabled. The software must save the data
> to be restored in a dedicated location in SAR RAM.

Some general comments:

- can the cluster PM notifier be used for the save path?

- This patch adds lots of data that is immediately removed by the next
  patch.  Probably the two just need to be combined.

- BUG_ON() should not be used unless there is absolutely no recovery
  path, since it casues a full kernel panic.   Instead, some error
  recovery should be added.

Kevin

  reply	other threads:[~2012-05-16 22:58 UTC|newest]

Thread overview: 87+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-14 10:18 [PATCHv2 00/19] ARM: OMAP4: device off support Tero Kristo
2012-05-14 10:18 ` [PATCHv2 01/19] ARM: OMAP4: PM: powerdomain: Add HWSAR flag to L3INIT Tero Kristo
2012-05-16 18:27   ` Kevin Hilman
2012-05-14 10:18 ` [PATCHv2 02/19] ARM: OMAP4: Add SAR ROM base address Tero Kristo
2012-05-16 18:28   ` Kevin Hilman
2012-05-21  8:28     ` Tero Kristo
2012-05-14 10:18 ` [PATCHv2 03/19] ARM: OMAP4: PM: Add device-off support Tero Kristo
2012-05-16 22:36   ` Kevin Hilman
2012-05-17  7:10     ` Shilimkar, Santosh
2012-05-21  8:48     ` Tero Kristo
2012-05-21 14:05       ` Jean Pihet
2012-05-29 18:34         ` Kevin Hilman
2012-05-29 18:31       ` Kevin Hilman
2012-05-30  8:20         ` Tero Kristo
2012-05-14 10:18 ` [PATCHv2 04/19] ARM: OMAP4: PM: save/restore all DPLL settings in OFF mode Tero Kristo
2012-05-16 22:42   ` Kevin Hilman
2012-05-17  7:04     ` Shilimkar, Santosh
2012-05-17  8:52       ` Shilimkar, Santosh
2012-05-17 16:37         ` Kevin Hilman
2012-05-21  9:01           ` Tero Kristo
2012-05-29 19:46         ` Menon, Nishanth
2012-05-30 17:59           ` Kevin Hilman
2012-05-30 18:24             ` Menon, Nishanth
2012-05-30 22:09               ` Kevin Hilman
2012-05-31  2:38                 ` Shilimkar, Santosh
2012-05-21  8:58     ` Tero Kristo
2012-05-14 10:18 ` [PATCHv2 05/19] ARM: OMAP4: PM: save/restore all CM1/2 " Tero Kristo
2012-05-16 22:48   ` Kevin Hilman
2012-05-17  7:05     ` Shilimkar, Santosh
2012-05-14 10:18 ` [PATCHv2 06/19] ARM: OMAP4: PM: Add SAR backup support towards device OFF Tero Kristo
2012-05-16 22:58   ` Kevin Hilman [this message]
2012-05-17  7:02     ` Shilimkar, Santosh
2012-05-17 16:42       ` Kevin Hilman
2012-05-18  5:53         ` Shilimkar, Santosh
2012-05-21  9:07           ` Tero Kristo
2012-05-14 10:18 ` [PATCHv2 07/19] ARM: OMAP4: Auto generate SAR layout contents Tero Kristo
2012-05-14 10:18 ` [PATCHv2 08/19] ARM: OMAP4: SAR: generate overwrite data based on SAR ROM contents Tero Kristo
2012-05-14 10:18 ` [PATCHv2 09/19] ARM: OMAP4: PM: add errata support Tero Kristo
2012-05-29 20:10   ` Menon, Nishanth
2012-05-30  8:32     ` Tero Kristo
2012-05-30 14:45       ` Menon, Nishanth
2012-05-14 10:18 ` [PATCHv2 10/19] ARM: OMAP4: PM: Work-around for ROM code BUG of IVAHD/TESLA Tero Kristo
2012-05-16 23:05   ` Kevin Hilman
2012-05-16 23:07     ` Kevin Hilman
2012-05-21  9:11       ` Tero Kristo
2012-05-29 20:13         ` Kevin Hilman
2012-05-17  6:52     ` Shilimkar, Santosh
2012-05-17 16:45       ` Kevin Hilman
2012-05-18  5:55         ` Shilimkar, Santosh
2012-05-14 10:18 ` [PATCHv2 11/19] ARM: OMAP4: PM: save/restore CM L3INSTR registers when MPU hits OSWR/OFF mode Tero Kristo
2012-05-16 23:17   ` Kevin Hilman
2012-05-17  6:53     ` Shilimkar, Santosh
2012-05-14 10:18 ` [PATCHv2 12/19] ARM: OMAP4: PM: update ROM return address for OSWR and OFF Tero Kristo
2012-05-16 23:36   ` Kevin Hilman
2012-05-21  9:29     ` Tero Kristo
2012-05-14 10:18 ` [PATCHv2 13/19] ARM: OMAP4: PM: Mark the PPI and SPI interrupts as non-secure for GP Tero Kristo
2012-05-16 23:48   ` Kevin Hilman
2012-05-21  9:32     ` Tero Kristo
2012-05-14 10:18 ` [PATCHv2 14/19] ARM: OMAP4: wakeupgen: enable clocks for save_secure_all Tero Kristo
2012-05-17  0:06   ` Kevin Hilman
2012-05-21  9:38     ` Tero Kristo
2012-05-21  9:43       ` Shilimkar, Santosh
2012-05-29 20:15       ` Kevin Hilman
2012-05-29 20:48         ` Menon, Nishanth
2012-05-30  8:44           ` Tero Kristo
2012-05-30  8:33         ` Tero Kristo
2012-05-17  0:17   ` Paul Walmsley
2012-05-21  9:35     ` Tero Kristo
2012-05-21  9:39       ` Shilimkar, Santosh
2012-05-14 10:18 ` [PATCHv2 15/19] ARM: OMAP4430: PM: workaround for DDR corruption on second CS Tero Kristo
2012-05-17  0:15   ` Kevin Hilman
2012-05-17  7:12     ` Shilimkar, Santosh
2012-05-17 16:47       ` Kevin Hilman
2012-05-18  5:55         ` Shilimkar, Santosh
2012-05-14 10:18 ` [PATCHv2 16/19] TEMP: ARM: OMAP4: prevent voltage transitions Tero Kristo
2012-05-14 10:18 ` [PATCHv2 17/19] ARM: OMAP4: put cpu1 back to sleep if no wake request Tero Kristo
2012-05-17  0:31   ` Kevin Hilman
2012-05-21 10:21     ` Tero Kristo
2012-05-21 10:40       ` Shilimkar, Santosh
2012-05-29 20:17         ` Kevin Hilman
2012-05-30 15:18         ` Menon, Nishanth
2012-05-14 10:18 ` [PATCHv2 18/19] ARM: OMAP4460: wakeupgen: set GIC_CPU0 backup status flag always Tero Kristo
2012-05-17  0:33   ` Kevin Hilman
2012-05-21  9:12     ` Tero Kristo
2012-05-14 10:18 ` [PATCHv2 19/19] ARM: OMAP4: powerdomain: update mpu / core off counters during device off Tero Kristo
2012-05-30 21:08   ` Menon, Nishanth
2012-05-31  6:50     ` Tero Kristo

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