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From: Russell King <rmk+kernel@arm.linux.org.uk>
To: alsa-devel@alsa-project.org, b43-dev@lists.infradead.org,
	devel@driverdev.osuosl.org, devicetree@vger.kernel.org,
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Cc: Vinod Koul <vinod.koul@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Rob Landley <rob@landley.net>
Subject: [PATCH 01/51] DMA-API: provide a helper to set both DMA and coherent DMA masks
Date: Thu, 19 Sep 2013 22:25:58 +0100
Message-ID: <E1VMlja-0007fA-HU@rmk-PC.arm.linux.org.uk> (raw)
In-Reply-To: <20130919212235.GD12758@n2100.arm.linux.org.uk>

Provide a helper to set both the DMA and coherent DMA masks to the
same value - this avoids duplicated code in a number of drivers,
sometimes with buggy error handling, and also allows us identify
which drivers do things differently.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
 Documentation/DMA-API-HOWTO.txt |   37 ++++++++++++++++++++++---------------
 Documentation/DMA-API.txt       |    8 ++++++++
 include/linux/dma-mapping.h     |   14 ++++++++++++++
 3 files changed, 44 insertions(+), 15 deletions(-)

diff --git a/Documentation/DMA-API-HOWTO.txt b/Documentation/DMA-API-HOWTO.txt
index 14129f1..5e98303 100644
--- a/Documentation/DMA-API-HOWTO.txt
+++ b/Documentation/DMA-API-HOWTO.txt
@@ -101,14 +101,23 @@ style to do this even if your device holds the default setting,
 because this shows that you did think about these issues wrt. your
 device.
 
-The query is performed via a call to dma_set_mask():
+The query is performed via a call to dma_set_mask_and_coherent():
 
-	int dma_set_mask(struct device *dev, u64 mask);
+	int dma_set_mask_and_coherent(struct device *dev, u64 mask);
 
-The query for consistent allocations is performed via a call to
-dma_set_coherent_mask():
+which will query the mask for both streaming and coherent APIs together.
+If you have some special requirements, then the following two separate
+queries can be used instead:
 
-	int dma_set_coherent_mask(struct device *dev, u64 mask);
+	The query for streaming mappings is performed via a call to
+	dma_set_mask():
+
+		int dma_set_mask(struct device *dev, u64 mask);
+
+	The query for consistent allocations is performed via a call
+	to dma_set_coherent_mask():
+
+		int dma_set_coherent_mask(struct device *dev, u64 mask);
 
 Here, dev is a pointer to the device struct of your device, and mask
 is a bit mask describing which bits of an address your device
@@ -137,7 +146,7 @@ exactly why.
 
 The standard 32-bit addressing device would do something like this:
 
-	if (dma_set_mask(dev, DMA_BIT_MASK(32))) {
+	if (dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32))) {
 		printk(KERN_WARNING
 		       "mydev: No suitable DMA available.\n");
 		goto ignore_this_device;
@@ -171,22 +180,20 @@ If a card is capable of using 64-bit consistent allocations as well,
 
 	int using_dac, consistent_using_dac;
 
-	if (!dma_set_mask(dev, DMA_BIT_MASK(64))) {
+	if (!dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64))) {
 		using_dac = 1;
 	   	consistent_using_dac = 1;
-		dma_set_coherent_mask(dev, DMA_BIT_MASK(64));
-	} else if (!dma_set_mask(dev, DMA_BIT_MASK(32))) {
+	} else if (!dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32))) {
 		using_dac = 0;
 		consistent_using_dac = 0;
-		dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
 	} else {
 		printk(KERN_WARNING
 		       "mydev: No suitable DMA available.\n");
 		goto ignore_this_device;
 	}
 
-dma_set_coherent_mask() will always be able to set the same or a
-smaller mask as dma_set_mask(). However for the rare case that a
+The coherent coherent mask will always be able to set the same or a
+smaller mask as the streaming mask. However for the rare case that a
 device driver only uses consistent allocations, one would have to
 check the return value from dma_set_coherent_mask().
 
@@ -199,9 +206,9 @@ Finally, if your device can only drive the low 24-bits of
 		goto ignore_this_device;
 	}
 
-When dma_set_mask() is successful, and returns zero, the kernel saves
-away this mask you have provided.  The kernel will use this
-information later when you make DMA mappings.
+When dma_set_mask() or dma_set_mask_and_coherent() is successful, and
+returns zero, the kernel saves away this mask you have provided.  The
+kernel will use this information later when you make DMA mappings.
 
 There is a case which we are aware of at this time, which is worth
 mentioning in this documentation.  If your device supports multiple
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index 78a6c56..e865279 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -142,6 +142,14 @@ internal API for use by the platform than an external API for use by
 driver writers.
 
 int
+dma_set_mask_and_coherent(struct device *dev, u64 mask)
+
+Checks to see if the mask is possible and updates the device
+streaming and coherent DMA mask parameters if it is.
+
+Returns: 0 if successful and a negative error if not.
+
+int
 dma_set_mask(struct device *dev, u64 mask)
 
 Checks to see if the mask is possible and updates the device
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 3a8d0a2..ec951f9 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -97,6 +97,20 @@ static inline int dma_set_coherent_mask(struct device *dev, u64 mask)
 }
 #endif
 
+/*
+ * Set both the DMA mask and the coherent DMA mask to the same thing.
+ * Note that we don't check the return value from dma_set_coherent_mask()
+ * as the DMA API guarantees that the coherent DMA mask can be set to
+ * the same or smaller than the streaming DMA mask.
+ */
+static inline int dma_set_mask_and_coherent(struct device *dev, u64 mask)
+{
+	int rc = dma_set_mask(dev, mask);
+	if (rc == 0)
+		dma_set_coherent_mask(dev, mask);
+	return rc;
+}
+
 extern u64 dma_get_required_mask(struct device *dev);
 
 static inline unsigned int dma_get_max_seg_size(struct device *dev)
-- 
1.7.4.4

  reply index

Thread overview: 95+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-19 21:22 [PATCH 00/51] DMA mask changes Russell King - ARM Linux
2013-09-19 21:25 ` Russell King [this message]
     [not found]   ` <E1VMlja-0007fA-HU-eh5Bv4kxaXIANfyc6IWni62ZND6+EDdj@public.gmane.org>
2013-09-20  1:21     ` [PATCH 01/51] DMA-API: provide a helper to set both DMA and coherent DMA masks Ben Hutchings
     [not found]       ` <1379640097.2500.4.camel-/LGg1Z1CJKQ+9kgCwbf1HqK4ta4zdZpAajtMo4Cw6ucAvxtiuMwx3w@public.gmane.org>
2013-09-20 14:12         ` Russell King - ARM Linux
2013-09-19 21:26 ` [PATCH 02/51] DMA-API: net: brocade/bna/bnad.c: fix 32-bit DMA mask handling Russell King
2013-09-19 21:27 ` [PATCH 03/51] DMA-API: net: intel/e1000e: " Russell King
2013-09-20 19:48   ` Jeff Kirsher
2013-09-19 21:30 ` [PATCH 06/51] DMA-API: net: intel/ixgb: " Russell King
2013-09-20 19:50   ` Jeff Kirsher
2013-09-19 21:31 ` [PATCH 07/51] DMA-API: net: intel/ixgbe: " Russell King
2013-09-20 19:51   ` Jeff Kirsher
2013-09-19 21:34 ` [PATCH 10/51] DMA-API: net: broadcom/bnx2x: replace dma_set_mask()+dma_set_coherent_mask() with new helper Russell King
2013-09-19 21:37 ` [PATCH 12/51] DMA-API: net: intel/e1000: " Russell King
2013-09-20 19:45   ` Jeff Kirsher
2013-09-19 21:38 ` [PATCH 13/51] DMA-API: net: sfc/efx.c: " Russell King
2013-09-19 21:39 ` [PATCH 14/51] DMA-API: net: b43: " Russell King
2013-09-19 21:40 ` [PATCH 15/51] DMA-API: net: b43legacy: " Russell King
2013-09-19 21:41 ` [PATCH 16/51] DMA-API: ppc: vio.c: " Russell King
2013-11-15 16:16   ` Cedric Le Goater
2013-09-19 21:42 ` [PATCH 17/51] DMA-API: block: nvme-core: " Russell King
2013-09-19 21:43 ` [PATCH 18/51] DMA-API: staging: et131x: " Russell King
2013-09-19 21:44 ` [PATCH 19/51] DMA-API: media: dt3155v4l: " Russell King
2013-09-30 11:57   ` Hans Verkuil
     [not found]     ` <5249673B.5020705-qWit8jRvyhVmR6Xm/wNWPw@public.gmane.org>
2013-10-31 11:46       ` Mauro Carvalho Chehab
2013-10-31 14:49         ` Russell King - ARM Linux
2013-09-19 21:45 ` [PATCH 20/51] DMA-API: usb: bcma: " Russell King
2013-09-19 21:46 ` [PATCH 21/51] DMA-API: usb: ssb-hcd: " Russell King
2013-09-19 21:47 ` [PATCH 22/51] DMA-API: amba: get rid of separate dma_mask Russell King
2013-09-22 12:18   ` Grant Likely
2013-09-19 21:48 ` [PATCH 23/51] DMA-API: dma: pl08x: add dma_set_mask_and_coherent() call Russell King
     [not found]   ` <E1VMm4v-0007hz-RC-eh5Bv4kxaXIANfyc6IWni62ZND6+EDdj@public.gmane.org>
2013-09-23 10:12     ` [alsa-devel] " Vinod Koul
2013-09-19 21:49 ` [PATCH 24/51] DMA-API: dma: pl330: " Russell King
     [not found]   ` <E1VMm5t-0007i5-V7-eh5Bv4kxaXIANfyc6IWni62ZND6+EDdj@public.gmane.org>
2013-09-20 17:26     ` Heiko Stübner
2013-09-21 20:00       ` Russell King - ARM Linux
2013-09-23 10:43         ` [alsa-devel] " Vinod Koul
2013-09-19 21:50 ` [PATCH 25/51] DMA-API: video: clcd: " Russell King
2013-09-19 21:51 ` [PATCH 26/51] DMA-API: usb: ohci-sa1111: add a note about DMA masks Russell King
2013-09-19 21:53 ` [PATCH 28/51] DMA-API: sound: fix dma mask handling in a lot of drivers Russell King
2013-09-20 16:36   ` Mark Brown
2013-09-26  7:51   ` Takashi Iwai
2013-09-26  7:54     ` Russell King - ARM Linux
2013-09-26  8:25       ` Takashi Iwai
2013-09-26  8:29         ` Takashi Iwai
2013-09-19 21:54 ` [PATCH 29/51] DMA-API: ata: pata_octeon_cf: convert to use dma_coerce_mask_and_coherent() Russell King
2013-10-30 19:08   ` Geert Uytterhoeven
2013-09-19 21:55 ` [PATCH 30/51] DMA-API: dma: dw_dmac.c: " Russell King
2013-09-19 21:56 ` [PATCH 31/51] DMA-API: media: omap3isp: " Russell King
     [not found]   ` <E1VMmCg-0007j1-Pi-eh5Bv4kxaXIANfyc6IWni62ZND6+EDdj@public.gmane.org>
2013-09-27  1:56     ` Laurent Pinchart
2013-09-19 21:57 ` [PATCH 32/51] DMA-API: mmc: sdhci-acpi: " Russell King
2013-09-19 21:58 ` [PATCH 33/51] DMA-API: net: nxp/lpc_eth: " Russell King
2013-09-19 21:59 ` [PATCH 34/51] DMA-API: net: octeon: " Russell King
2013-09-19 22:00 ` [PATCH 35/51] DMA-API: parport: parport_pc.c: " Russell King
2013-09-19 22:01 ` [PATCH 36/51] DMA-API: usb: use dma_set_coherent_mask() Russell King
2013-09-20 13:08   ` Felipe Balbi
2013-09-23 12:30   ` Nicolas Ferre
2013-09-23 18:27   ` Alan Stern
     [not found]     ` <Pine.LNX.4.44L0.1309231418030.1348-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-09-23 18:42       ` Russell King - ARM Linux
2013-09-19 22:02 ` [PATCH 37/51] DMA-API: usb: use new dma_coerce_mask_and_coherent() Russell King
2013-09-20 13:10   ` Felipe Balbi
     [not found]   ` <E1VMmIV-0007jw-Gq-eh5Bv4kxaXIANfyc6IWni62ZND6+EDdj@public.gmane.org>
2013-09-23 12:34     ` Nicolas Ferre
2013-09-19 22:03 ` [PATCH 38/51] DMA-API: staging: use dma_set_coherent_mask() Russell King
2013-09-19 23:11 ` [PATCH 39/51] DMA-API: others: " Russell King
2013-09-20 12:16   ` Tejun Heo
2013-09-20 12:18     ` Tejun Heo
2013-09-20 14:00     ` Russell King - ARM Linux
2013-09-20 22:20       ` Tejun Heo
2013-09-26 10:51   ` Archit Taneja
2013-09-19 23:12 ` [PATCH 40/51] DMA-API: crypto: fix ixp4xx crypto platform device support Russell King
2013-09-19 23:13 ` [PATCH 41/51] DMA-API: crypto: remove last references to 'static struct device *dev' Russell King
2013-09-19 23:14 ` [PATCH 42/51] DMA-API: usb: musb: use platform_device_register_full() to avoid directly messing with dma masks Russell King
2013-09-20 13:11   ` Felipe Balbi
2013-09-20 13:49     ` Russell King - ARM Linux
2013-09-20 15:15       ` Felipe Balbi
     [not found] ` <20130919212235.GD12758-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2013-09-19 21:28   ` [PATCH 04/51] DMA-API: net: intel/igb: fix 32-bit DMA mask handling Russell King
2013-09-20 19:49     ` Jeff Kirsher
2013-09-19 21:29   ` [PATCH 05/51] DMA-API: net: intel/igbvf: " Russell King
2013-09-20 19:49     ` Jeff Kirsher
2013-09-19 21:32   ` [PATCH 08/51] DMA-API: net: intel/ixgbevf: " Russell King
2013-09-20 19:51     ` Jeff Kirsher
2013-09-19 21:33   ` [PATCH 09/51] DMA-API: net: broadcom/b44: replace dma_set_mask()+dma_set_coherent_mask() with new helper Russell King
2013-09-19 21:36   ` [PATCH 11/51] DMA-API: net: emulex/benet: " Russell King
2013-09-19 21:52   ` [PATCH 27/51] DMA-API: provide a helper to setup DMA masks Russell King
2013-09-19 23:15   ` [PATCH 43/51] DMA-API: dma: edma.c: no need to explicitly initialize " Russell King
2013-09-23 10:25     ` [alsa-devel] " Vinod Koul
2013-09-23 11:37       ` Russell King - ARM Linux
2013-09-19 23:16   ` [PATCH 44/51] DMA-API: dcdbas: update DMA mask handing Russell King
2013-09-19 23:17 ` [PATCH 45/51] DMA-API: firmware/google/gsmi.c: avoid direct access to DMA masks Russell King
2013-09-19 23:39 ` [PATCH 46/51] ARM: DMA-API: better handing of DMA masks for coherent allocations Russell King
2013-09-19 23:40 ` [PATCH 47/51] ARM: 7794/1: block: Rename parameter dma_mask to max_addr for blk_queue_bounce_limit() Russell King
2013-09-19 23:41 ` [PATCH 48/51] ARM: 7795/1: mm: dma-mapping: Add dma_max_pfn(dev) helper function Russell King
2013-09-19 23:42 ` [PATCH 49/51] ARM: 7796/1: scsi: Use dma_max_pfn(dev) helper for bounce_limit calculations Russell King
2013-09-19 23:43 ` [PATCH 50/51] ARM: 7797/1: mmc: " Russell King
2013-09-19 23:44 ` [PATCH 51/51] ARM: 7805/1: mm: change max*pfn to include the physical offset of memory Russell King
2013-09-26 20:23 ` [PATCH 00/51] DMA mask changes Rafał Miłecki
2013-09-27  8:27   ` Russell King - ARM Linux

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