cregit-Linux how code gets into the kernel

Release 4.11 arch/arm/include/asm/dma.h

#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 < (0x10000000 - PAGE_OFFSET) ? \
                (PAGE_OFFSET + arm_dma_zone_size) : 0xffffffffUL; })
#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; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)2288.00%133.33%
Linus Torvalds28.00%133.33%
Thomas Gleixner14.00%133.33%
Total25100.00%3100.00%


static inline void release_dma_lock(unsigned long flags) { raw_spin_unlock_irqrestore(&dma_spin_lock, flags); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)1684.21%133.33%
Linus Torvalds210.53%133.33%
Thomas Gleixner15.26%133.33%
Total19100.00%3100.00%

/* 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 *)__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 */ #ifdef CONFIG_PCI extern int isa_dma_bridge_buggy; #else #define isa_dma_bridge_buggy (0) #endif #endif /* __ASM_ARM_DMA_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)19664.90%936.00%
Russell King9130.13%936.00%
Linus Torvalds41.32%14.00%
Thomas Gleixner30.99%14.00%
Peter Hüwe30.99%14.00%
Nico Pitre20.66%14.00%
Santosh Shilimkar10.33%14.00%
Christoph Hellwig10.33%14.00%
Arnd Bergmann10.33%14.00%
Total302100.00%25100.00%
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