[PATCH] of: amba: use of_dma_configure for AMBA devices

On Thu, Sep 18, 2014 at 01:55:36PM +0100, Catalin Marinas wrote:

On Thu, Sep 18, 2014 at 12:35:32PM +0100, Robin Murphy wrote:

quoted

On 17/09/14 19:05, Will Deacon wrote:

quoted

On Wed, Sep 17, 2014 at 06:47:19PM +0100, Rob Herring wrote:

quoted

On Wed, Sep 17, 2014 at 12:03 PM, Will Deacon [off-list ref] wrote:

quoted

On Wed, Sep 17, 2014 at 12:56:07PM +0100, Robin Murphy wrote:

quoted

Commit 591c1e ("of: configure the platform device dma parameters)
introduced a common mechanism to configure DMA from DT properties.
AMBA devices created from DT can take advantage of this, too.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>

   Acked-by: Will Deacon [off-list ref]

It would be great if the arm-soc guys can pick this up.

Is this a dependency for something else? If so,

Acked-by: Rob Herring <robh@kernel.org>

Yeah, it's going to be needed by my IOMMU init rework so that AMBA devices
get registered with their IOMMUs.

Noob question: Does that mean I should resend (with ACKs) to 
arm at kernel.org? (I wasn't entirely sure where this should go, hence just 
throwing at the list with CCs)

If it is not part of a larger series you want to merge, Rob could pick
it up (he could add the acks as well).

Alternatively, I can get it via the arm64 tree together with an
additional patch removing the bus hooks in dma-mapping.c (maybe that's a
better option if no-one objects).

So I plan to take this patch via the arm64 tree together with the patch
below (after some more testing):

----8<----------------------------

From 2189064795dc3fb4101e5c34d28c6b62b8a3bfd9 Mon Sep 17 00:00:00 2001

From: Catalin Marinas <catalin.marinas@arm.com>
Date: Mon, 22 Sep 2014 11:48:31 +0100
Subject: [PATCH] arm64: Implement set_arch_dma_coherent_ops() to replace bus
 notifiers

Commit 6ecba8eb51b7 (arm64: Use bus notifiers to set per-device coherent
DMA ops) introduced bus notifiers to set the coherent dma ops based on
the 'dma-coherent' DT property. Since the generic of_dma_configure()
handles this property for platform and AMBA devices, replace the
notifiers with set_arch_dma_coherent_ops().

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 arch/arm64/include/asm/dma-mapping.h |  7 +++++++
 arch/arm64/mm/dma-mapping.c          | 31 -------------------------------
 2 files changed, 7 insertions(+), 31 deletions(-)

diff --git a/arch/arm64/include/asm/dma-mapping.h b/arch/arm64/include/asm/dma-mapping.h
index dc82e52acdb3..adeae3f6f0fc 100644
--- a/arch/arm64/include/asm/dma-mapping.h
+++ b/arch/arm64/include/asm/dma-mapping.h

@@ -52,6 +52,13 @@ static inline void set_dma_ops(struct device *dev, struct dma_map_ops *ops)
 	dev->archdata.dma_ops = ops;
 }
 
+static inline int set_arch_dma_coherent_ops(struct device *dev)
+{
+	set_dma_ops(dev, &coherent_swiotlb_dma_ops);
+	return 0;
+}
+#define set_arch_dma_coherent_ops	set_arch_dma_coherent_ops
+
 #include <asm-generic/dma-mapping-common.h>
 
 static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 4164c5ace9f8..d6ceb3df0047 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c

@@ -22,11 +22,8 @@
 #include <linux/slab.h>
 #include <linux/dma-mapping.h>
 #include <linux/dma-contiguous.h>
-#include <linux/of.h>
-#include <linux/platform_device.h>
 #include <linux/vmalloc.h>
 #include <linux/swiotlb.h>
-#include <linux/amba/bus.h>
 
 #include <asm/cacheflush.h>
 

@@ -308,40 +305,12 @@ struct dma_map_ops coherent_swiotlb_dma_ops = {
 };
 EXPORT_SYMBOL(coherent_swiotlb_dma_ops);
 
-static int dma_bus_notifier(struct notifier_block *nb,
-			    unsigned long event, void *_dev)
-{
-	struct device *dev = _dev;
-
-	if (event != BUS_NOTIFY_ADD_DEVICE)
-		return NOTIFY_DONE;
-
-	if (of_property_read_bool(dev->of_node, "dma-coherent"))
-		set_dma_ops(dev, &coherent_swiotlb_dma_ops);
-
-	return NOTIFY_OK;
-}
-
-static struct notifier_block platform_bus_nb = {
-	.notifier_call = dma_bus_notifier,
-};
-
-static struct notifier_block amba_bus_nb = {
-	.notifier_call = dma_bus_notifier,
-};
-
 extern int swiotlb_late_init_with_default_size(size_t default_size);
 
 static int __init swiotlb_late_init(void)
 {
 	size_t swiotlb_size = min(SZ_64M, MAX_ORDER_NR_PAGES << PAGE_SHIFT);
 
-	/*
-	 * These must be registered before of_platform_populate().
-	 */
-	bus_register_notifier(&platform_bus_type, &platform_bus_nb);
-	bus_register_notifier(&amba_bustype, &amba_bus_nb);
-
 	dma_ops = &noncoherent_swiotlb_dma_ops;
 
 	return swiotlb_late_init_with_default_size(swiotlb_size);