From mboxrd@z Thu Jan 1 00:00:00 1970 From: maxime.ripard@free-electrons.com (Maxime Ripard) Date: Tue, 1 Apr 2014 18:22:16 +0200 Subject: [PATCH v5] ARM: sun4i: spi: Allow transfers larger than FIFO size In-Reply-To: <1396318611-8997-1-git-send-email-mr.nuke.me@gmail.com> References: <20140331104522.GD26751@lukather> <1396318611-8997-1-git-send-email-mr.nuke.me@gmail.com> Message-ID: <20140401162216.GN26751@lukather> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Mar 31, 2014 at 09:16:51PM -0500, Alexandru Gagniuc wrote: > SPI transfers were limited to one FIFO depth, which is 64 bytes. > This was an artificial limitation, however, as the hardware can handle > much larger bursts. To accommodate this, we enable the interrupt when > the Rx FIFO is 3/4 full, and drain the FIFO within the interrupt > handler. The 3/4 ratio was chosen arbitrarily, with the intention to > reduce the potential number of interrupts. > > Since the SUN4I_CTL_TP bit is set, the hardware will pause > transmission whenever the FIFO is full, so there is no risk of losing > data if we can't service the interrupt in time. > > For the Tx side, enable and use the Tx FIFO 3/4 empty interrupt to > replenish the FIFO on large SPI bursts. This requires more care in > when the interrupt is left enabled, as this interrupt will continually > trigger when the FIFO is less than 1/4 full, even though we > acknowledge it. > > Signed-off-by: Alexandru Gagniuc > Acked-by: Maxime Ripard Hmmm, you forgot to Cc Mark Brown. Please resubmit it Ccing whoever shows up using get_maintainer, otherwise, your patch won't be applied. You also forgot the changes between this version and the previous one. Thanks! Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 836 bytes Desc: Digital signature URL: