From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [PATCH v3 08/12] Serial: OMAP2+: Make the RX_TIMEOUT for DMA configurable for each UART Date: Fri, 24 Jun 2011 17:16:47 -0700 Message-ID: <87liwqrci8.fsf@ti.com> References: <1307532194-13039-1-git-send-email-govindraj.raja@ti.com> <1307532194-13039-9-git-send-email-govindraj.raja@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: <1307532194-13039-9-git-send-email-govindraj.raja@ti.com> (Govindraj R.'s message of "Wed, 8 Jun 2011 16:53:10 +0530") Sender: linux-serial-owner@vger.kernel.org To: "Govindraj.R" Cc: linux-omap@vger.kernel.org, linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Tony Lindgren , Jon Hunter List-Id: linux-omap@vger.kernel.org "Govindraj.R" writes: > From: Jon Hunter > > When using DMA there are two timeouts defined. The first timeout, > rx_timeout, is really a polling rate in which software polls the > DMA status to see if the DMA has finished. This is necessary for > the RX side because we do not know how much data we will receive. > The secound timeout, RX_TIMEOUT, is a timeout after which the > DMA will be stopped if no more data is received. To make this > clearer, rename rx_timeout as rx_poll_rate and rename the > function serial_omap_rx_timeout() to serial_omap_rxdma_poll(). > > The OMAP-Serial driver defines an RX_TIMEOUT of 3 seconds that is > used to indicate when the DMA for UART can be stopped if no more > data is received. The value is a global definition that is applied > to all instances of the UART. > > Each UART may be used for a different purpose and so the timeout > required may differ. Make this value configurable for each UART so > that this value can be optimised for power savings. > > Signed-off-by: Jon Hunter > Signed-off-by: Govindraj.R Acked-by: Kevin Hilman Jon, thanks (again) for the well-written, descriptive changelog. Kevin From mboxrd@z Thu Jan 1 00:00:00 1970 From: khilman@ti.com (Kevin Hilman) Date: Fri, 24 Jun 2011 17:16:47 -0700 Subject: [PATCH v3 08/12] Serial: OMAP2+: Make the RX_TIMEOUT for DMA configurable for each UART In-Reply-To: <1307532194-13039-9-git-send-email-govindraj.raja@ti.com> (Govindraj R.'s message of "Wed, 8 Jun 2011 16:53:10 +0530") References: <1307532194-13039-1-git-send-email-govindraj.raja@ti.com> <1307532194-13039-9-git-send-email-govindraj.raja@ti.com> Message-ID: <87liwqrci8.fsf@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org "Govindraj.R" writes: > From: Jon Hunter > > When using DMA there are two timeouts defined. The first timeout, > rx_timeout, is really a polling rate in which software polls the > DMA status to see if the DMA has finished. This is necessary for > the RX side because we do not know how much data we will receive. > The secound timeout, RX_TIMEOUT, is a timeout after which the > DMA will be stopped if no more data is received. To make this > clearer, rename rx_timeout as rx_poll_rate and rename the > function serial_omap_rx_timeout() to serial_omap_rxdma_poll(). > > The OMAP-Serial driver defines an RX_TIMEOUT of 3 seconds that is > used to indicate when the DMA for UART can be stopped if no more > data is received. The value is a global definition that is applied > to all instances of the UART. > > Each UART may be used for a different purpose and so the timeout > required may differ. Make this value configurable for each UART so > that this value can be optimised for power savings. > > Signed-off-by: Jon Hunter > Signed-off-by: Govindraj.R Acked-by: Kevin Hilman Jon, thanks (again) for the well-written, descriptive changelog. Kevin