cregit-Linux how code gets into the kernel

Release 4.7 arch/sh/drivers/dma/dmabrg.c

/*
 * SH7760 DMABRG IRQ handling
 *
 * (c) 2007 MSC Vertriebsges.m.b.H, Manuel Lauss <mlau@msc-ge.com>
 *  licensed under the GPLv2.
 *
 */

#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <asm/dma.h>
#include <asm/dmabrg.h>
#include <asm/io.h>

/*
 * The DMABRG is a special DMA unit within the SH7760. It does transfers
 * from USB-SRAM/Audio units to main memory (and also the LCDC; but that
 * part is sensibly placed  in the LCDC  registers and requires no irqs)
 * It has 3 IRQ lines which trigger 10 events, and works independently
 * from the traditional SH DMAC (although it blocks usage of DMAC 0)
 *
 * BRGIRQID   | component | dir | meaning      | source
 * -----------------------------------------------------
 *     0      | USB-DMA   | ... | xfer done    | DMABRGI1
 *     1      | USB-UAE   | ... | USB addr err.| DMABRGI0
 *     2      | HAC0/SSI0 | play| all done     | DMABRGI1
 *     3      | HAC0/SSI0 | play| half done    | DMABRGI2
 *     4      | HAC0/SSI0 | rec | all done     | DMABRGI1
 *     5      | HAC0/SSI0 | rec | half done    | DMABRGI2
 *     6      | HAC1/SSI1 | play| all done     | DMABRGI1
 *     7      | HAC1/SSI1 | play| half done    | DMABRGI2
 *     8      | HAC1/SSI1 | rec | all done     | DMABRGI1
 *     9      | HAC1/SSI1 | rec | half done    | DMABRGI2
 *
 * all can be enabled/disabled in the DMABRGCR register,
 * as well as checked if they occurred.
 *
 * DMABRGI0 services  USB  DMA  Address  errors,  but it still must be
 * enabled/acked in the DMABRGCR register.  USB-DMA complete indicator
 * is grouped together with the audio buffer end indicators, too bad...
 *
 * DMABRGCR:    Bits 31-24: audio-dma ENABLE flags,
 *              Bits 23-16: audio-dma STATUS flags,
 *              Bits  9-8:  USB error/xfer ENABLE,
 *              Bits  1-0:  USB error/xfer STATUS.
 *      Ack an IRQ by writing 0 to the STATUS flag.
 *      Mask IRQ by writing 0 to ENABLE flag.
 *
 * Usage is almost like with any other IRQ:
 *  dmabrg_request_irq(BRGIRQID, handler, data)
 *  dmabrg_free_irq(BRGIRQID)
 *
 * handler prototype:  void brgirqhandler(void *data)
 */


#define DMARSRA		0xfe090000

#define DMAOR		0xffa00040

#define DMACHCR0	0xffa0000c

#define DMABRGCR	0xfe3c0000


#define DMAOR_BRG	0x0000c000

#define DMAOR_DMEN	0x00000001


#define DMABRGI0	68

#define DMABRGI1	69

#define DMABRGI2	70


struct dmabrg_handler {
	
void (*handler)(void *);
	
void *data;
} 
*dmabrg_handlers;


static inline void dmabrg_call_handler(int i) { dmabrg_handlers[i].handler(dmabrg_handlers[i].data); }

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manuel laussmanuel lauss25100.00%1100.00%
Total25100.00%1100.00%

/* * main DMABRG irq handler. It acks irqs and then * handles every set and unmasked bit sequentially. * No locking and no validity checks; it should be * as fast as possible (audio!) */
static irqreturn_t dmabrg_irq(int irq, void *data) { unsigned long dcr; unsigned int i; dcr = __raw_readl(DMABRGCR); __raw_writel(dcr & ~0x00ff0003, DMABRGCR); /* ack all */ dcr &= dcr >> 8; /* ignore masked */ /* USB stuff, get it out of the way first */ if (dcr & 1) dmabrg_call_handler(DMABRGIRQ_USBDMA); if (dcr & 2) dmabrg_call_handler(DMABRGIRQ_USBDMAERR); /* Audio */ dcr >>= 16; while (dcr) { i = __ffs(dcr); dcr &= dcr - 1; dmabrg_call_handler(i + DMABRGIRQ_A0TXF); } return IRQ_HANDLED; }

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manuel laussmanuel lauss10198.06%150.00%
paul mundtpaul mundt21.94%150.00%
Total103100.00%2100.00%


static void dmabrg_disable_irq(unsigned int dmairq) { unsigned long dcr; dcr = __raw_readl(DMABRGCR); dcr &= ~(1 << ((dmairq > 1) ? dmairq + 22 : dmairq + 8)); __raw_writel(dcr, DMABRGCR); }

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manuel laussmanuel lauss4996.08%150.00%
paul mundtpaul mundt23.92%150.00%
Total51100.00%2100.00%


static void dmabrg_enable_irq(unsigned int dmairq) { unsigned long dcr; dcr = __raw_readl(DMABRGCR); dcr |= (1 << ((dmairq > 1) ? dmairq + 22 : dmairq + 8)); __raw_writel(dcr, DMABRGCR); }

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manuel laussmanuel lauss4896.00%150.00%
paul mundtpaul mundt24.00%150.00%
Total50100.00%2100.00%


int dmabrg_request_irq(unsigned int dmairq, void(*handler)(void*), void *data) { if ((dmairq > 9) || !handler) return -ENOENT; if (dmabrg_handlers[dmairq].handler) return -EBUSY; dmabrg_handlers[dmairq].handler = handler; dmabrg_handlers[dmairq].data = data; dmabrg_enable_irq(dmairq); return 0; }

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manuel laussmanuel lauss77100.00%1100.00%
Total77100.00%1100.00%

EXPORT_SYMBOL_GPL(dmabrg_request_irq);
void dmabrg_free_irq(unsigned int dmairq) { if (likely(dmairq < 10)) { dmabrg_disable_irq(dmairq); dmabrg_handlers[dmairq].handler = NULL; dmabrg_handlers[dmairq].data = NULL; } }

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manuel laussmanuel lauss43100.00%1100.00%
Total43100.00%1100.00%

EXPORT_SYMBOL_GPL(dmabrg_free_irq);
static int __init dmabrg_init(void) { unsigned long or; int ret; dmabrg_handlers = kzalloc(10 * sizeof(struct dmabrg_handler), GFP_KERNEL); if (!dmabrg_handlers) return -ENOMEM; #ifdef CONFIG_SH_DMA /* request DMAC channel 0 before anyone else can get it */ ret = request_dma(0, "DMAC 0 (DMABRG)"); if (ret < 0) printk(KERN_INFO "DMABRG: DMAC ch0 not reserved!\n"); #endif __raw_writel(0, DMABRGCR); __raw_writel(0, DMACHCR0); __raw_writel(0x94000000, DMARSRA); /* enable DMABRG in DMAC 0 */ /* enable DMABRG mode, enable the DMAC */ or = __raw_readl(DMAOR); __raw_writel(or | DMAOR_BRG | DMAOR_DMEN, DMAOR); ret = request_irq(DMABRGI0, dmabrg_irq, 0, "DMABRG USB address error", NULL); if (ret) goto out0; ret = request_irq(DMABRGI1, dmabrg_irq, 0, "DMABRG Transfer End", NULL); if (ret) goto out1; ret = request_irq(DMABRGI2, dmabrg_irq, 0, "DMABRG Transfer Half", NULL); if (ret == 0) return ret; free_irq(DMABRGI1, NULL); out1: free_irq(DMABRGI0, NULL); out0: kfree(dmabrg_handlers); return ret; }

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manuel laussmanuel lauss19295.05%125.00%
paul mundtpaul mundt52.48%125.00%
yong zhangyong zhang31.49%125.00%
julia lawalljulia lawall20.99%125.00%
Total202100.00%4100.00%

subsys_initcall(dmabrg_init);

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PersonTokensPropCommitsCommitProp
manuel laussmanuel lauss62496.89%116.67%
paul mundtpaul mundt111.71%116.67%
yong zhangyong zhang30.47%116.67%
tejun heotejun heo30.47%116.67%
julia lawalljulia lawall20.31%116.67%
simon arlottsimon arlott10.16%116.67%
Total644100.00%6100.00%
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