From mboxrd@z Thu Jan 1 00:00:00 1970 From: maxime.ripard@bootlin.com (Maxime Ripard) Date: Mon, 9 Apr 2018 11:27:30 +0200 Subject: [PATCH v3 3/6] spi: sun6i: restrict transfer length in PIO-mode In-Reply-To: <204e97cb-2f39-00f0-fd4e-3aa9a51f7cac@orpaltech.com> References: <20180403154449.2443-1-ssuloev@orpaltech.com> <20180403154449.2443-4-ssuloev@orpaltech.com> <20180404065048.n76r3ytuznd6fqsl@flea> <20180405091913.ky4dnmszoobn2xry@flea> <20180405131735.GB12349@sirena.org.uk> <8159c3a5-af74-9f13-aedb-7ecc708bdff6@orpaltech.com> <20180406073441.xesojvzc3deljhoy@flea> <204e97cb-2f39-00f0-fd4e-3aa9a51f7cac@orpaltech.com> Message-ID: <20180409092730.2moyhl5aaktjwbyn@flea> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Apr 06, 2018 at 06:48:23PM +0300, Sergey Suloev wrote: > On 04/06/2018 10:34 AM, Maxime Ripard wrote: > > On Thu, Apr 05, 2018 at 04:44:16PM +0300, Sergey Suloev wrote: > > > On 04/05/2018 04:17 PM, Mark Brown wrote: > > > > On Thu, Apr 05, 2018 at 12:59:35PM +0300, Sergey Suloev wrote: > > > > > On 04/05/2018 12:19 PM, Maxime Ripard wrote: > > > > > > The point of that patch was precisely to allow to send more data than > > > > > > the FIFO. You're breaking that behaviour without any justification, > > > > > > and this is not ok. > > > > > I am sorry, but you can't. That's a hardware limitation. > > > > Are you positive about that? Normally you can add things to hardware > > > > FIFOs while they're being drained so so long as you can keep data > > > > flowing in at least as fast as it's being consumed. > > > Well, normally yes, but this is not the case with the hardware that I own. > > > My a20 (BPiM1+) and a31 (BPiM2) boards behaves differently. With a transfer > > > larger than FIFO then TC interrupt never happens. > > Because you're not supposed to have a transfer larger than the FIFO, > > but to have to setup at first a transfer the size of the FIFO, and > > then when it's (or starts to be) depleted, fill it up again. > > According to what you said the driver must implement > "transfer_one_message" instead of "transfer_one" I'm not sure what makes you think that I said that. Maxime -- Maxime Ripard, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 833 bytes Desc: not available URL: