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// SPDX-License-Identifier: GPL-2.0
/*
* SH7760 DMABRG IRQ handling
*
* (c) 2007 MSC Vertriebsges.m.b.H, Manuel Lauss <mlau@msc-ge.com>
*/
#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);
}
/*
* 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;
}
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);
}
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);
}
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;
}
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;
}
}
EXPORT_SYMBOL_GPL(dmabrg_free_irq);
static int __init dmabrg_init(void)
{
unsigned long or;
int ret;
dmabrg_handlers = kcalloc(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;
}
subsys_initcall(dmabrg_init);
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