From mboxrd@z Thu Jan 1 00:00:00 1970 From: thierry.reding@gmail.com (Thierry Reding) Date: Fri, 17 Jul 2015 11:57:55 +0200 Subject: [PATCH V3 02/19] memory: tegra: Add MC flush support In-Reply-To: <1436791197-32358-3-git-send-email-jonathanh@nvidia.com> References: <1436791197-32358-1-git-send-email-jonathanh@nvidia.com> <1436791197-32358-3-git-send-email-jonathanh@nvidia.com> Message-ID: <20150717095754.GG3057@ulmo> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Jul 13, 2015 at 01:39:40PM +0100, Jon Hunter wrote: > The Tegra memory controller implements a flush feature to flush pending > accesses and prevent further accesses from occurring. This feature is > used when powering down IP blocks to ensure the IP block is in a good > state. The flushes are organised by software groups and IP blocks are > assigned in hardware to the different software groups. Add helper > functions for requesting a handle to an MC flush for a given > software group and enabling/disabling the MC flush itself. > > This is based upon a change by Vince Hsu . > > Signed-off-by: Jon Hunter > --- > drivers/memory/tegra/mc.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++ > drivers/memory/tegra/mc.h | 2 + > include/soc/tegra/mc.h | 34 ++++++++++++++ > 3 files changed, 146 insertions(+) Do we know if this is actually necessary? I remember having a discussion with Arnd Bergmann a while ago, and the Linux driver model kind of assumes that by the time a device is disabled all outstanding accesses will have stopped. Do we have a way to determine that this even makes a difference? Can we trigger a case where not doing this would cause breakage and see that adding this fixes that particular issue? Thierry -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: not available URL: