arch/sh/drivers/dma/dmabrg.c

   1 /*
   2  * SH7760 DMABRG IRQ handling
   3  *
   4  * (c) 2007 MSC Vertriebsges.m.b.H, Manuel Lauss <mlau@msc-ge.com>
   5  *  licensed under the GPLv2.
   6  *
   7  */
   8
   9 #include <linux/interrupt.h>
  10 #include <linux/kernel.h>
  11 #include <linux/slab.h>
  12 #include <asm/dma.h>
  13 #include <asm/dmabrg.h>
  14 #include <asm/io.h>
  15
  16 /*
  17  * The DMABRG is a special DMA unit within the SH7760. It does transfers
  18  * from USB-SRAM/Audio units to main memory (and also the LCDC; but that
  19  * part is sensibly placed  in the LCDC  registers and requires no irqs)
  20  * It has 3 IRQ lines which trigger 10 events, and works independently
  21  * from the traditional SH DMAC (although it blocks usage of DMAC 0)
  22  *
  23  * BRGIRQID   | component | dir | meaning      | source
  24  * -----------------------------------------------------
  25  *     0      | USB-DMA   | ... | xfer done    | DMABRGI1
  26  *     1      | USB-UAE   | ... | USB addr err.| DMABRGI0
  27  *     2      | HAC0/SSI0 | play| all done     | DMABRGI1
  28  *     3      | HAC0/SSI0 | play| half done    | DMABRGI2
  29  *     4      | HAC0/SSI0 | rec | all done     | DMABRGI1
  30  *     5      | HAC0/SSI0 | rec | half done    | DMABRGI2
  31  *     6      | HAC1/SSI1 | play| all done     | DMABRGI1
  32  *     7      | HAC1/SSI1 | play| half done    | DMABRGI2
  33  *     8      | HAC1/SSI1 | rec | all done     | DMABRGI1
  34  *     9      | HAC1/SSI1 | rec | half done    | DMABRGI2
  35  *
  36  * all can be enabled/disabled in the DMABRGCR register,
  37  * as well as checked if they occurred.
  38  *
  39  * DMABRGI0 services  USB  DMA  Address  errors,  but it still must be
  40  * enabled/acked in the DMABRGCR register.  USB-DMA complete indicator
  41  * is grouped together with the audio buffer end indicators, too bad...
  42  *
  43  * DMABRGCR:    Bits 31-24: audio-dma ENABLE flags,
  44  *              Bits 23-16: audio-dma STATUS flags,
  45  *              Bits  9-8:  USB error/xfer ENABLE,
  46  *              Bits  1-0:  USB error/xfer STATUS.
  47  *      Ack an IRQ by writing 0 to the STATUS flag.
  48  *      Mask IRQ by writing 0 to ENABLE flag.
  49  *
  50  * Usage is almost like with any other IRQ:
  51  *  dmabrg_request_irq(BRGIRQID, handler, data)
  52  *  dmabrg_free_irq(BRGIRQID)
  53  *
  54  * handler prototype:  void brgirqhandler(void *data)
  55  */
  56
  57 #define DMARSRA         0xfe090000
  58 #define DMAOR           0xffa00040
  59 #define DMACHCR0        0xffa0000c
  60 #define DMABRGCR        0xfe3c0000
  61
  62 #define DMAOR_BRG       0x0000c000
  63 #define DMAOR_DMEN      0x00000001
  64
  65 #define DMABRGI0        68
  66 #define DMABRGI1        69
  67 #define DMABRGI2        70
  68
  69 struct dmabrg_handler {
  70         void (*handler)(void *);
  71         void *data;
  72 } *dmabrg_handlers;
  73
  74 static inline void dmabrg_call_handler(int i)
  75 {
  76         dmabrg_handlers[i].handler(dmabrg_handlers[i].data);
  77 }
  78
  79 /*
  80  * main DMABRG irq handler. It acks irqs and then
  81  * handles every set and unmasked bit sequentially.
  82  * No locking and no validity checks; it should be
  83  * as fast as possible (audio!)
  84  */
  85 static irqreturn_t dmabrg_irq(int irq, void *data)
  86 {
  87         unsigned long dcr;
  88         unsigned int i;
  89
  90         dcr = __raw_readl(DMABRGCR);
  91         __raw_writel(dcr & ~0x00ff0003, DMABRGCR);      /* ack all */
  92         dcr &= dcr >> 8;        /* ignore masked */
  93
  94         /* USB stuff, get it out of the way first */
  95         if (dcr & 1)
  96                 dmabrg_call_handler(DMABRGIRQ_USBDMA);
  97         if (dcr & 2)
  98                 dmabrg_call_handler(DMABRGIRQ_USBDMAERR);
  99
 100         /* Audio */
 101         dcr >>= 16;
 102         while (dcr) {
 103                 i = __ffs(dcr);
 104                 dcr &= dcr - 1;
 105                 dmabrg_call_handler(i + DMABRGIRQ_A0TXF);
 106         }
 107         return IRQ_HANDLED;
 108 }
 109
 110 static void dmabrg_disable_irq(unsigned int dmairq)
 111 {
 112         unsigned long dcr;
 113         dcr = __raw_readl(DMABRGCR);
 114         dcr &= ~(1 << ((dmairq > 1) ? dmairq + 22 : dmairq + 8));
 115         __raw_writel(dcr, DMABRGCR);
 116 }
 117
 118 static void dmabrg_enable_irq(unsigned int dmairq)
 119 {
 120         unsigned long dcr;
 121         dcr = __raw_readl(DMABRGCR);
 122         dcr |= (1 << ((dmairq > 1) ? dmairq + 22 : dmairq + 8));
 123         __raw_writel(dcr, DMABRGCR);
 124 }
 125
 126 int dmabrg_request_irq(unsigned int dmairq, void(*handler)(void*),
 127                        void *data)
 128 {
 129         if ((dmairq > 9) || !handler)
 130                 return -ENOENT;
 131         if (dmabrg_handlers[dmairq].handler)
 132                 return -EBUSY;
 133
 134         dmabrg_handlers[dmairq].handler = handler;
 135         dmabrg_handlers[dmairq].data = data;
 136
 137         dmabrg_enable_irq(dmairq);
 138         return 0;
 139 }
 140 EXPORT_SYMBOL_GPL(dmabrg_request_irq);
 141
 142 void dmabrg_free_irq(unsigned int dmairq)
 143 {
 144         if (likely(dmairq < 10)) {
 145                 dmabrg_disable_irq(dmairq);
 146                 dmabrg_handlers[dmairq].handler = NULL;
 147                 dmabrg_handlers[dmairq].data = NULL;
 148         }
 149 }
 150 EXPORT_SYMBOL_GPL(dmabrg_free_irq);
 151
 152 static int __init dmabrg_init(void)
 153 {
 154         unsigned long or;
 155         int ret;
 156
 157         dmabrg_handlers = kzalloc(10 * sizeof(struct dmabrg_handler),
 158                                   GFP_KERNEL);
 159         if (!dmabrg_handlers)
 160                 return -ENOMEM;
 161
 162 #ifdef CONFIG_SH_DMA
 163         /* request DMAC channel 0 before anyone else can get it */
 164         ret = request_dma(0, "DMAC 0 (DMABRG)");
 165         if (ret < 0)
 166                 printk(KERN_INFO "DMABRG: DMAC ch0 not reserved!\n");
 167 #endif
 168
 169         __raw_writel(0, DMABRGCR);
 170         __raw_writel(0, DMACHCR0);
 171         __raw_writel(0x94000000, DMARSRA);      /* enable DMABRG in DMAC 0 */
 172
 173         /* enable DMABRG mode, enable the DMAC */
 174         or = __raw_readl(DMAOR);
 175         __raw_writel(or | DMAOR_BRG | DMAOR_DMEN, DMAOR);
 176
 177         ret = request_irq(DMABRGI0, dmabrg_irq, IRQF_DISABLED,
 178                         "DMABRG USB address error", NULL);
 179         if (ret)
 180                 goto out0;
 181
 182         ret = request_irq(DMABRGI1, dmabrg_irq, IRQF_DISABLED,
 183                         "DMABRG Transfer End", NULL);
 184         if (ret)
 185                 goto out1;
 186
 187         ret = request_irq(DMABRGI2, dmabrg_irq, IRQF_DISABLED,
 188                         "DMABRG Transfer Half", NULL);
 189         if (ret == 0)
 190                 return ret;
 191
 192         free_irq(DMABRGI1, 0);
 193 out1:   free_irq(DMABRGI0, 0);
 194 out0:   kfree(dmabrg_handlers);
 195         return ret;
 196 }
 197 subsys_initcall(dmabrg_init);