From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753175AbbINWwG (ORCPT ); Mon, 14 Sep 2015 18:52:06 -0400 Received: from v094114.home.net.pl ([79.96.170.134]:60079 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752286AbbINWwB (ORCPT ); Mon, 14 Sep 2015 18:52:01 -0400 From: "Rafael J. Wysocki" To: Mika Westerberg Cc: Greg Kroah-Hartman , Vinod Koul , Dan Williams , Andy Shevchenko , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] acpi-dma: Add support for "dma-names" device property Date: Tue, 15 Sep 2015 01:19:59 +0200 Message-ID: <2758429.Hja1JGjCVP@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/4.1.0-rc5+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <1442241456-75340-2-git-send-email-mika.westerberg@linux.intel.com> References: <1442241456-75340-1-git-send-email-mika.westerberg@linux.intel.com> <1442241456-75340-2-git-send-email-mika.westerberg@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday, September 14, 2015 05:37:36 PM Mika Westerberg wrote: > The current implementation hard codes the two supported channels so that > "tx" is always 0 and "rx" is always 1. This is because there has been no > suitable way in ACPI to name resources. > > With _DSD device properties we can finally do this: > > Device (SPI1) { > Name (_CRS, ResourceTemplate () { > ... > FixedDMA (0x0000, 0x0000, Width32bit) > FixedDMA (0x0001, 0x0001, Width32bit) > }) > > Name (_DSD, Package () { > ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), > Package () { > Package () {"dma-names", Package () {"tx", "rx"}} > }, > }) > } > > The names "tx" and "rx" now provide index of the FixedDMA resource in > question. > > Modify acpi_dma_request_slave_chan_by_name() so that it looks for > "dma-names" property first and only then fall back using hardcoded indices. > > The DT "dma-names" binding that we reuse for ACPI is documented in > Documentation/devicetree/bindings/dma/dma.txt. > > Signed-off-by: Mika Westerberg This and the [1/2] both look reasonable to me, but I need an ACK from Vinod for this one. > --- > drivers/dma/acpi-dma.c | 25 +++++++++++++++++-------- > 1 file changed, 17 insertions(+), 8 deletions(-) > > diff --git a/drivers/dma/acpi-dma.c b/drivers/dma/acpi-dma.c > index 5a635646e05c..981a38fc4cb8 100644 > --- a/drivers/dma/acpi-dma.c > +++ b/drivers/dma/acpi-dma.c > @@ -21,6 +21,7 @@ > #include > #include > #include > +#include > > static LIST_HEAD(acpi_dma_list); > static DEFINE_MUTEX(acpi_dma_lock); > @@ -413,21 +414,29 @@ EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_index); > * translate the names "tx" and "rx" here based on the most common case where > * the first FixedDMA descriptor is TX and second is RX. > * > + * If the device has "dma-names" property the FixedDMA descriptor indices > + * are retrieved based on those. Otherwise the function falls back using > + * hardcoded indices. > + * > * Return: > * Pointer to appropriate dma channel on success or an error pointer. > */ > struct dma_chan *acpi_dma_request_slave_chan_by_name(struct device *dev, > const char *name) > { > - size_t index; > - > - if (!strcmp(name, "tx")) > - index = 0; > - else if (!strcmp(name, "rx")) > - index = 1; > - else > - return ERR_PTR(-ENODEV); > + int index; > + > + index = device_property_match_string(dev, "dma-names", name); > + if (index < 0) { > + if (!strcmp(name, "tx")) > + index = 0; > + else if (!strcmp(name, "rx")) > + index = 1; > + else > + return ERR_PTR(-ENODEV); > + } > > + dev_dbg(dev, "found DMA channel \"%s\" at index %d\n", name, index); > return acpi_dma_request_slave_chan_by_index(dev, index); > } > EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_name); > Thanks, Rafael