From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Likely Subject: Re: [PATCH 3/5] serial: pl011: use generic DMA slave configuration if possible Date: Tue, 05 Feb 2013 14:22:38 +0000 Message-ID: <20130205142238.3F3AB3E1265@localhost> References: <1359395857-1235-1-git-send-email-arnd@arndb.de> <1359395857-1235-4-git-send-email-arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Vinod Koul , Viresh Kumar , devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, Greg Kroah-Hartman , spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Andy Shevchenko , Jiri Slaby To: Arnd Bergmann , linux-arm-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Return-path: In-Reply-To: <1359395857-1235-4-git-send-email-arnd-r2nGTMty4D4@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: "devicetree-discuss" List-Id: linux-spi.vger.kernel.org On Mon, 28 Jan 2013 17:57:35 +0000, Arnd Bergmann wrote: > With the new OF DMA binding, it is possible to completely avoid the > need for platform_data for configuring a DMA channel. In cases where the > platform has already been converted, calling dma_request_slave_channel > should get all the necessary information from the device tree. > > Like the patch that converts the dw_dma controller, this is completely > untested and is looking for someone to try it out. > > Signed-off-by: Arnd Bergmann > Cc: Grant Likely > Cc: Jiri Slaby > Cc: Greg Kroah-Hartman > Cc: Linus Walleij > Cc: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org > Cc: Viresh Kumar > Cc: Andy Shevchenko > Cc: Vinod Koul > Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org > Cc: linux-arm-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Acked-by: Grant Likely > --- > drivers/tty/serial/amba-pl011.c | 62 ++++++++++++++++++++++++----------------- > 1 file changed, 37 insertions(+), 25 deletions(-) > > diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c > index 3ea5408..c25b00e 100644 > --- a/drivers/tty/serial/amba-pl011.c > +++ b/drivers/tty/serial/amba-pl011.c > @@ -245,7 +245,7 @@ static void pl011_sgbuf_free(struct dma_chan *chan, struct pl011_sgbuf *sg, > } > } > > -static void pl011_dma_probe_initcall(struct uart_amba_port *uap) > +static void pl011_dma_probe_initcall(struct device *dev, struct uart_amba_port *uap) > { > /* DMA is the sole user of the platform data right now */ > struct amba_pl011_data *plat = uap->port.dev->platform_data; > @@ -259,20 +259,25 @@ static void pl011_dma_probe_initcall(struct uart_amba_port *uap) > struct dma_chan *chan; > dma_cap_mask_t mask; > > - /* We need platform data */ > - if (!plat || !plat->dma_filter) { > - dev_info(uap->port.dev, "no DMA platform data\n"); > - return; > - } > + chan = dma_request_slave_channel(dev, "tx"); > > - /* Try to acquire a generic DMA engine slave TX channel */ > - dma_cap_zero(mask); > - dma_cap_set(DMA_SLAVE, mask); > - > - chan = dma_request_channel(mask, plat->dma_filter, plat->dma_tx_param); > if (!chan) { > - dev_err(uap->port.dev, "no TX DMA channel!\n"); > - return; > + /* We need platform data */ > + if (!plat || !plat->dma_filter) { > + dev_info(uap->port.dev, "no DMA platform data\n"); > + return; > + } > + > + /* Try to acquire a generic DMA engine slave TX channel */ > + dma_cap_zero(mask); > + dma_cap_set(DMA_SLAVE, mask); > + > + chan = dma_request_channel(mask, plat->dma_filter, > + plat->dma_tx_param); > + if (!chan) { > + dev_err(uap->port.dev, "no TX DMA channel!\n"); > + return; > + } > } > > dmaengine_slave_config(chan, &tx_conf); > @@ -282,7 +287,18 @@ static void pl011_dma_probe_initcall(struct uart_amba_port *uap) > dma_chan_name(uap->dmatx.chan)); > > /* Optionally make use of an RX channel as well */ > - if (plat->dma_rx_param) { > + chan = dma_request_slave_channel(dev, "rx"); > + > + if (!chan && plat->dma_rx_param) { > + chan = dma_request_channel(mask, plat->dma_filter, plat->dma_rx_param); > + > + if (!chan) { > + dev_err(uap->port.dev, "no RX DMA channel!\n"); > + return; > + } > + } > + > + if (chan) { > struct dma_slave_config rx_conf = { > .src_addr = uap->port.mapbase + UART01x_DR, > .src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE, > @@ -291,12 +307,6 @@ static void pl011_dma_probe_initcall(struct uart_amba_port *uap) > .device_fc = false, > }; > > - chan = dma_request_channel(mask, plat->dma_filter, plat->dma_rx_param); > - if (!chan) { > - dev_err(uap->port.dev, "no RX DMA channel!\n"); > - return; > - } > - > dmaengine_slave_config(chan, &rx_conf); > uap->dmarx.chan = chan; > > @@ -315,6 +325,7 @@ static void pl011_dma_probe_initcall(struct uart_amba_port *uap) > struct dma_uap { > struct list_head node; > struct uart_amba_port *uap; > + struct device *dev; > }; > > static LIST_HEAD(pl011_dma_uarts); > @@ -325,7 +336,7 @@ static int __init pl011_dma_initcall(void) > > list_for_each_safe(node, tmp, &pl011_dma_uarts) { > struct dma_uap *dmau = list_entry(node, struct dma_uap, node); > - pl011_dma_probe_initcall(dmau->uap); > + pl011_dma_probe_initcall(dmau->dev, dmau->uap); > list_del(node); > kfree(dmau); > } > @@ -334,18 +345,19 @@ static int __init pl011_dma_initcall(void) > > device_initcall(pl011_dma_initcall); > > -static void pl011_dma_probe(struct uart_amba_port *uap) > +static void pl011_dma_probe(struct device *dev, struct uart_amba_port *uap) > { > struct dma_uap *dmau = kzalloc(sizeof(struct dma_uap), GFP_KERNEL); > if (dmau) { > dmau->uap = uap; > + dmau->dev = dev; > list_add_tail(&dmau->node, &pl011_dma_uarts); > } > } > #else > -static void pl011_dma_probe(struct uart_amba_port *uap) > +static void pl011_dma_probe(struct device *dev, struct uart_amba_port *uap) > { > - pl011_dma_probe_initcall(uap); > + pl011_dma_probe_initcall(dev, uap); > } > #endif > > @@ -2020,7 +2032,7 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id) > uap->port.ops = &amba_pl011_pops; > uap->port.flags = UPF_BOOT_AUTOCONF; > uap->port.line = i; > - pl011_dma_probe(uap); > + pl011_dma_probe(&dev->dev, uap); > > /* Ensure interrupts from this UART are masked and cleared */ > writew(0, uap->port.membase + UART011_IMSC); > -- > 1.8.0 > -- Grant Likely, B.Sc, P.Eng. 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