From 4313a24985f00340eeb591fd66aa2b257b9e0a69 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 23 May 2022 21:59:02 +0200 Subject: arch/*/: remove CONFIG_VIRT_TO_BUS All architecture-independent users of virt_to_bus() and bus_to_virt() have been fixed to use the dma mapping interfaces or have been removed now. This means the definitions on most architectures, and the CONFIG_VIRT_TO_BUS symbol are now obsolete and can be removed. The only exceptions to this are a few network and scsi drivers for m68k Amiga and VME machines and ppc32 Macintosh. These drivers work correctly with the old interfaces and are probably not worth changing. On alpha and parisc, virt_to_bus() were still used in asm/floppy.h. alpha can use isa_virt_to_bus() like x86 does, and parisc can just open-code the virt_to_phys() here, as this is architecture specific code. I tried updating the bus-virt-phys-mapping.rst documentation, which started as an email from Linus to explain some details of the Linux-2.0 driver interfaces. The bits about virt_to_bus() were declared obsolete backin 2000, and the rest is not all that relevant any more, so in the end I just decided to remove the file completely. Reviewed-by: Geert Uytterhoeven Acked-by: Geert Uytterhoeven Acked-by: Michael Ellerman (powerpc) Acked-by: Helge Deller # parisc Signed-off-by: Arnd Bergmann --- Documentation/core-api/dma-api-howto.rst | 14 -------------- 1 file changed, 14 deletions(-) (limited to 'Documentation/core-api/dma-api-howto.rst') diff --git a/Documentation/core-api/dma-api-howto.rst b/Documentation/core-api/dma-api-howto.rst index 358d495456d1..828846804e25 100644 --- a/Documentation/core-api/dma-api-howto.rst +++ b/Documentation/core-api/dma-api-howto.rst @@ -707,20 +707,6 @@ to use the dma_sync_*() interfaces:: } } -Drivers converted fully to this interface should not use virt_to_bus() any -longer, nor should they use bus_to_virt(). Some drivers have to be changed a -little bit, because there is no longer an equivalent to bus_to_virt() in the -dynamic DMA mapping scheme - you have to always store the DMA addresses -returned by the dma_alloc_coherent(), dma_pool_alloc(), and dma_map_single() -calls (dma_map_sg() stores them in the scatterlist itself if the platform -supports dynamic DMA mapping in hardware) in your driver structures and/or -in the card registers. - -All drivers should be using these interfaces with no exceptions. It -is planned to completely remove virt_to_bus() and bus_to_virt() as -they are entirely deprecated. Some ports already do not provide these -as it is impossible to correctly support them. - Handling Errors =============== -- cgit v1.2.3