diff options
Diffstat (limited to 'arch/arm/include/asm/dma.h')
| -rw-r--r-- | arch/arm/include/asm/dma.h | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/arch/arm/include/asm/dma.h b/arch/arm/include/asm/dma.h new file mode 100644 index 0000000000..e2a1916013 --- /dev/null +++ b/arch/arm/include/asm/dma.h @@ -0,0 +1,149 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_ARM_DMA_H +#define __ASM_ARM_DMA_H + +/* + * This is the maximum virtual address which can be DMA'd from. + */ +#ifndef CONFIG_ZONE_DMA +#define MAX_DMA_ADDRESS 0xffffffffUL +#else +#define MAX_DMA_ADDRESS ({ \ + extern phys_addr_t arm_dma_zone_size; \ + arm_dma_zone_size && arm_dma_zone_size < (0x100000000ULL - PAGE_OFFSET) ? \ + (PAGE_OFFSET + arm_dma_zone_size) : 0xffffffffUL; }) + +extern phys_addr_t arm_dma_limit; +#define ARCH_LOW_ADDRESS_LIMIT arm_dma_limit +#endif + +#ifdef CONFIG_ISA_DMA_API +/* + * This is used to support drivers written for the x86 ISA DMA API. + * It should not be re-used except for that purpose. + */ +#include <linux/spinlock.h> +#include <linux/scatterlist.h> + +#include <mach/isa-dma.h> + +/* + * The DMA modes reflect the settings for the ISA DMA controller + */ +#define DMA_MODE_MASK 0xcc + +#define DMA_MODE_READ 0x44 +#define DMA_MODE_WRITE 0x48 +#define DMA_MODE_CASCADE 0xc0 +#define DMA_AUTOINIT 0x10 + +extern raw_spinlock_t dma_spin_lock; + +static inline unsigned long claim_dma_lock(void) +{ + unsigned long flags; + raw_spin_lock_irqsave(&dma_spin_lock, flags); + return flags; +} + +static inline void release_dma_lock(unsigned long flags) +{ + raw_spin_unlock_irqrestore(&dma_spin_lock, flags); +} + +/* Clear the 'DMA Pointer Flip Flop'. + * Write 0 for LSB/MSB, 1 for MSB/LSB access. + */ +#define clear_dma_ff(chan) + +/* Set only the page register bits of the transfer address. + * + * NOTE: This is an architecture specific function, and should + * be hidden from the drivers + */ +extern void set_dma_page(unsigned int chan, char pagenr); + +/* Request a DMA channel + * + * Some architectures may need to do allocate an interrupt + */ +extern int request_dma(unsigned int chan, const char * device_id); + +/* Free a DMA channel + * + * Some architectures may need to do free an interrupt + */ +extern void free_dma(unsigned int chan); + +/* Enable DMA for this channel + * + * On some architectures, this may have other side effects like + * enabling an interrupt and setting the DMA registers. + */ +extern void enable_dma(unsigned int chan); + +/* Disable DMA for this channel + * + * On some architectures, this may have other side effects like + * disabling an interrupt or whatever. + */ +extern void disable_dma(unsigned int chan); + +/* Test whether the specified channel has an active DMA transfer + */ +extern int dma_channel_active(unsigned int chan); + +/* Set the DMA scatter gather list for this channel + * + * This should not be called if a DMA channel is enabled, + * especially since some DMA architectures don't update the + * DMA address immediately, but defer it to the enable_dma(). + */ +extern void set_dma_sg(unsigned int chan, struct scatterlist *sg, int nr_sg); + +/* Set the DMA address for this channel + * + * This should not be called if a DMA channel is enabled, + * especially since some DMA architectures don't update the + * DMA address immediately, but defer it to the enable_dma(). + */ +extern void __set_dma_addr(unsigned int chan, void *addr); +#define set_dma_addr(chan, addr) \ + __set_dma_addr(chan, (void *)isa_bus_to_virt(addr)) + +/* Set the DMA byte count for this channel + * + * This should not be called if a DMA channel is enabled, + * especially since some DMA architectures don't update the + * DMA count immediately, but defer it to the enable_dma(). + */ +extern void set_dma_count(unsigned int chan, unsigned long count); + +/* Set the transfer direction for this channel + * + * This should not be called if a DMA channel is enabled, + * especially since some DMA architectures don't update the + * DMA transfer direction immediately, but defer it to the + * enable_dma(). + */ +extern void set_dma_mode(unsigned int chan, unsigned int mode); + +/* Set the transfer speed for this channel + */ +extern void set_dma_speed(unsigned int chan, int cycle_ns); + +/* Get DMA residue count. After a DMA transfer, this + * should return zero. Reading this while a DMA transfer is + * still in progress will return unpredictable results. + * If called before the channel has been used, it may return 1. + * Otherwise, it returns the number of _bytes_ left to transfer. + */ +extern int get_dma_residue(unsigned int chan); + +#ifndef NO_DMA +#define NO_DMA 255 +#endif + +#endif /* CONFIG_ISA_DMA_API */ + +#endif /* __ASM_ARM_DMA_H */ |