From: thomas.petazzoni@free-electrons•com (Thomas Petazzoni)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 12/17] ARM: mvebu: Armada XP GP specific suspend/resume code
Date: Fri, 24 Oct 2014 16:28:24 +0200 [thread overview]
Message-ID: <20141024162824.67f9ce3d@free-electrons.com> (raw)
In-Reply-To: <20141024142044.GB3142@lunn.ch>
Dear Andrew Lunn,
On Fri, 24 Oct 2014 16:20:44 +0200, Andrew Lunn wrote:
> Does Marvell mandate this PIC and gpio interface? Or is a board
> designer free to implement it some other way? It seems to me, this
> should be considered specific to the Marvell reference design.
They don't mandate this interface, it's really a board-specific
decision, which is why I've split my implementation between:
* SoC-specific code, in mach-mvebu/pm.c.
* Board-specific code, in mach-mvebu/pm-board.c.
> I'm wondering if this code should be a power driver, living in
> drivers/power/reset/.
I'm fine with that, but have you seen the *very* tight interaction
between the SoC-specific code and the board-specific code? The problem
is that the board-specific code needs to put the SDRAM into
self-refresh *right* before shutting down the SoC, and all that while
making sure the code doing both of these operations remains in the
I-Cache, and does not touch any other location in memory (which has
become inaccessible due to being in self-refresh mode).
Look at the mvebu_armada_xp_gp_pm_enter() function: it takes two
arguments, received from the SoC-level code. How to handle this thing
with a driver in drivers/power/reset/ ?
> A few kirkwood boards have a PIC controlling the power. QNAP devices
> use a serial port to talk to it. Others use a single gpio line. Is
> there something to stop a designer doing this for XP?
Nothing stops that. I think Marvell told me they wanted to standardize
this GPIO interface with a PIC, but that's only for their own
development boards. Since it remains something outside the SoC, it is
by nature board-specific, and designers can do pretty much what they
want.
> It seems like you would have a more generic solution by allowing DT to
> specify a power off driver to use.
Sure, but see above. If you have some suggestion, I'm surely interested.
Best regards,
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
next prev parent reply other threads:[~2014-10-24 14:28 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-24 11:59 [PATCH 00/17] Suspend to RAM support for Armada XP Thomas Petazzoni
2014-10-24 11:59 ` [PATCH 01/17] Documentation: dt-bindings: minimal documentation for MVEBU SDRAM controller Thomas Petazzoni
2014-11-03 17:05 ` Gregory CLEMENT
2014-10-24 11:59 ` [PATCH 02/17] ARM: mvebu: enable strex backoff delay Thomas Petazzoni
2014-11-03 17:08 ` Gregory CLEMENT
2014-10-24 11:59 ` [PATCH 03/17] irqchip: irq-armada-370-xp: use proper return value for ->set_affinity() Thomas Petazzoni
2014-11-03 17:20 ` Gregory CLEMENT
2014-11-07 4:09 ` Jason Cooper
2014-10-24 11:59 ` [PATCH 04/17] irqchip: irq-armada-370-xp: suspend/resume support Thomas Petazzoni
2014-11-03 17:38 ` Gregory CLEMENT
2014-11-13 16:32 ` Thomas Petazzoni
2014-10-24 11:59 ` [PATCH 05/17] clocksource: time-armada-370-xp: add " Thomas Petazzoni
2014-11-03 17:45 ` Gregory CLEMENT
2014-10-24 11:59 ` [PATCH 06/17] gpio: mvebu: " Thomas Petazzoni
2014-10-24 16:30 ` David Cohen
2014-10-24 20:45 ` Andrew Lunn
2014-10-27 5:27 ` Alexandre Courbot
2014-10-27 17:45 ` David Cohen
2014-10-31 7:00 ` Linus Walleij
2014-10-31 7:52 ` Gregory CLEMENT
2014-10-31 8:14 ` Thomas Petazzoni
2014-11-03 13:26 ` Linus Walleij
2014-11-03 13:29 ` Linus Walleij
2014-11-03 17:53 ` Gregory CLEMENT
2014-11-03 21:21 ` Thomas Petazzoni
2014-10-24 11:59 ` [PATCH 07/17] bus: mvebu-mbus: " Thomas Petazzoni
2014-11-03 18:08 ` Gregory CLEMENT
2014-11-03 21:20 ` Thomas Petazzoni
2014-10-24 11:59 ` [PATCH 08/17] bus: mvebu-mbus: provide a mechanism to save SDRAM window configuration Thomas Petazzoni
2014-11-04 9:17 ` Gregory CLEMENT
2014-10-24 11:59 ` [PATCH 09/17] clk: mvebu: add suspend/resume for gatable clocks Thomas Petazzoni
2014-11-04 9:32 ` Gregory CLEMENT
2014-10-24 11:59 ` [PATCH 10/17] ARM: mvebu: implement suspend/resume support for Armada XP Thomas Petazzoni
2014-11-04 10:00 ` Gregory CLEMENT
2014-11-13 17:00 ` Thomas Petazzoni
2014-10-24 11:59 ` [PATCH 11/17] ARM: mvebu: reserve the first 10 KB of each memory bank for suspend/resume Thomas Petazzoni
2014-11-04 10:09 ` Gregory CLEMENT
2014-10-24 11:59 ` [PATCH 12/17] ARM: mvebu: Armada XP GP specific suspend/resume code Thomas Petazzoni
2014-10-24 14:20 ` Andrew Lunn
2014-10-24 14:28 ` Thomas Petazzoni [this message]
2014-10-24 14:51 ` Andrew Lunn
2014-10-27 12:51 ` Thomas Petazzoni
2014-10-27 14:19 ` Andrew Lunn
2014-10-27 14:40 ` Thomas Petazzoni
2014-10-27 14:59 ` Andrew Lunn
2014-10-27 15:12 ` Thomas Petazzoni
2014-10-27 15:15 ` Andrew Lunn
2014-11-10 13:53 ` Gregory CLEMENT
2014-10-24 11:59 ` [PATCH 13/17] ARM: mvebu: make sure MMU is disabled in armada_370_xp_cpu_resume Thomas Petazzoni
2014-11-10 14:05 ` Gregory CLEMENT
2014-10-24 11:59 ` [PATCH 14/17] ARM: mvebu: synchronize secondary CPU clocks on resume Thomas Petazzoni
2014-11-10 14:12 ` Gregory CLEMENT
2014-10-24 11:59 ` [PATCH 15/17] ARM: mvebu: add suspend/resume DT information for Armada XP GP Thomas Petazzoni
2014-11-10 14:14 ` Gregory CLEMENT
2014-10-24 11:59 ` [PATCH 16/17] ARM: mvebu: adjust mbus controller description on Armada 370/XP Thomas Petazzoni
2014-11-10 14:15 ` Gregory CLEMENT
2014-10-24 11:59 ` [PATCH 17/17] ARM: mvebu: add SDRAM controller description for Armada XP Thomas Petazzoni
2014-11-10 14:25 ` Gregory CLEMENT
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