Re: [PATCH 1/3] ARM/dma-mapping: move various helpers from dma-mapping.h to dma-direct.h
From: Robin Murphy <robin.murphy@arm.com>
Date: 2020-09-10 18:08:21
Also in:
linux-acpi, linux-devicetree, linux-iommu, linux-pci, linux-sh, linux-usb, lkml
On 2020-09-10 06:40, Christoph Hellwig wrote:
Move the helpers to translate to and from direct mapping DMA addresses to dma-direct.h. This not only is the most logical place, but the new placement also avoids dependency loops with pending commits.
For the straightforward move as it should be, Reviewed-by: Robin Murphy <robin.murphy@arm.com> However I do wonder how much of this could be cleaned up further...
quoted hunk ↗ jump to hunk
Signed-off-by: Christoph Hellwig <hch@lst.de> --- arch/arm/common/dmabounce.c | 2 +- arch/arm/include/asm/dma-direct.h | 70 ++++++++++++++++++++++++++++++ arch/arm/include/asm/dma-mapping.h | 70 ------------------------------ 3 files changed, 71 insertions(+), 71 deletions(-)diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c index f4b719bde76367..d3e00ea9208834 100644 --- a/arch/arm/common/dmabounce.c +++ b/arch/arm/common/dmabounce.c@@ -24,7 +24,7 @@ #include <linux/slab.h> #include <linux/page-flags.h> #include <linux/device.h> -#include <linux/dma-mapping.h> +#include <linux/dma-direct.h> #include <linux/dmapool.h> #include <linux/list.h> #include <linux/scatterlist.h>diff --git a/arch/arm/include/asm/dma-direct.h b/arch/arm/include/asm/dma-direct.h index 7c3001a6a775bf..de0f4ff9279615 100644 --- a/arch/arm/include/asm/dma-direct.h +++ b/arch/arm/include/asm/dma-direct.h@@ -2,6 +2,76 @@ #ifndef ASM_ARM_DMA_DIRECT_H #define ASM_ARM_DMA_DIRECT_H 1 +#include <asm/memory.h> + +#ifdef __arch_page_to_dma +#error Please update to __arch_pfn_to_dma +#endif
This must be long, long dead by now.
+
+/*
+ * dma_to_pfn/pfn_to_dma/dma_to_virt/virt_to_dma are architecture private
+ * functions used internally by the DMA-mapping API to provide DMA
+ * addresses. They must not be used by drivers.
+ */
+#ifndef __arch_pfn_to_dma
+static inline dma_addr_t pfn_to_dma(struct device *dev, unsigned long pfn)
+{
+ if (dev)
+ pfn -= dev->dma_pfn_offset;
+ return (dma_addr_t)__pfn_to_bus(pfn);
+}
+
+static inline unsigned long dma_to_pfn(struct device *dev, dma_addr_t addr)
+{
+ unsigned long pfn = __bus_to_pfn(addr);
+
+ if (dev)
+ pfn += dev->dma_pfn_offset;
+
+ return pfn;
+}These are only overridden for OMAP1510, and it looks like it wouldn't take much for the platform code or ohci-omap driver to set up a generic DMA offset for the relevant device.
+
+static inline void *dma_to_virt(struct device *dev, dma_addr_t addr)
+{
+ if (dev) {
+ unsigned long pfn = dma_to_pfn(dev, addr);
+
+ return phys_to_virt(__pfn_to_phys(pfn));
+ }
+
+ return (void *)__bus_to_virt((unsigned long)addr);
+}This appears entirely unused.
+
+static inline dma_addr_t virt_to_dma(struct device *dev, void *addr)
+{
+ if (dev)
+ return pfn_to_dma(dev, virt_to_pfn(addr));
+
+ return (dma_addr_t)__virt_to_bus((unsigned long)(addr));
+}And this is only used for some debug prints in dmabounce. Similarly the __bus_to_*()/__*_to_bus() calls themselves only appear significant to mach-footbridge any more, and could probably also be evolved into regular DMA offsets now that all API calls must have a non-NULL device. I think I might come back and take a closer look at all this at some point in future... :) Robin.
quoted hunk ↗ jump to hunk
+ +#else +static inline dma_addr_t pfn_to_dma(struct device *dev, unsigned long pfn) +{ + return __arch_pfn_to_dma(dev, pfn); +} + +static inline unsigned long dma_to_pfn(struct device *dev, dma_addr_t addr) +{ + return __arch_dma_to_pfn(dev, addr); +} + +static inline void *dma_to_virt(struct device *dev, dma_addr_t addr) +{ + return __arch_dma_to_virt(dev, addr); +} + +static inline dma_addr_t virt_to_dma(struct device *dev, void *addr) +{ + return __arch_virt_to_dma(dev, addr); +} +#endif + static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr) { unsigned int offset = paddr & ~PAGE_MASK;diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h index bdd80ddbca3451..0a1a536368c3a4 100644 --- a/arch/arm/include/asm/dma-mapping.h +++ b/arch/arm/include/asm/dma-mapping.h@@ -8,8 +8,6 @@ #include <linux/scatterlist.h> #include <linux/dma-debug.h> -#include <asm/memory.h> - #include <xen/xen.h> #include <asm/xen/hypervisor.h>@@ -23,74 +21,6 @@ static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus) return NULL; } -#ifdef __arch_page_to_dma -#error Please update to __arch_pfn_to_dma -#endif - -/* - * dma_to_pfn/pfn_to_dma/dma_to_virt/virt_to_dma are architecture private - * functions used internally by the DMA-mapping API to provide DMA - * addresses. They must not be used by drivers. - */ -#ifndef __arch_pfn_to_dma -static inline dma_addr_t pfn_to_dma(struct device *dev, unsigned long pfn) -{ - if (dev) - pfn -= dev->dma_pfn_offset; - return (dma_addr_t)__pfn_to_bus(pfn); -} - -static inline unsigned long dma_to_pfn(struct device *dev, dma_addr_t addr) -{ - unsigned long pfn = __bus_to_pfn(addr); - - if (dev) - pfn += dev->dma_pfn_offset; - - return pfn; -} - -static inline void *dma_to_virt(struct device *dev, dma_addr_t addr) -{ - if (dev) { - unsigned long pfn = dma_to_pfn(dev, addr); - - return phys_to_virt(__pfn_to_phys(pfn)); - } - - return (void *)__bus_to_virt((unsigned long)addr); -} - -static inline dma_addr_t virt_to_dma(struct device *dev, void *addr) -{ - if (dev) - return pfn_to_dma(dev, virt_to_pfn(addr)); - - return (dma_addr_t)__virt_to_bus((unsigned long)(addr)); -} - -#else -static inline dma_addr_t pfn_to_dma(struct device *dev, unsigned long pfn) -{ - return __arch_pfn_to_dma(dev, pfn); -} - -static inline unsigned long dma_to_pfn(struct device *dev, dma_addr_t addr) -{ - return __arch_dma_to_pfn(dev, addr); -} - -static inline void *dma_to_virt(struct device *dev, dma_addr_t addr) -{ - return __arch_dma_to_virt(dev, addr); -} - -static inline dma_addr_t virt_to_dma(struct device *dev, void *addr) -{ - return __arch_virt_to_dma(dev, addr); -} -#endif - /** * arm_dma_alloc - allocate consistent memory for DMA * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
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