arch/sh/drivers/dma/dmabrg.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * SH7760 DMABRG IRQ handling
   4  *
   5  * (c) 2007 MSC Vertriebsges.m.b.H, Manuel Lauss <mlau@msc-ge.com>
   6  */
   7
   8 #include <linux/interrupt.h>
   9 #include <linux/kernel.h>
  10 #include <linux/slab.h>
  11 #include <asm/dma.h>
  12 #include <asm/dmabrg.h>
  13 #include <asm/io.h>
  14
  15 /*
  16  * The DMABRG is a special DMA unit within the SH7760. It does transfers
  17  * from USB-SRAM/Audio units to main memory (and also the LCDC; but that
  18  * part is sensibly placed  in the LCDC  registers and requires no irqs)
  19  * It has 3 IRQ lines which trigger 10 events, and works independently
  20  * from the traditional SH DMAC (although it blocks usage of DMAC 0)
  21  *
  22  * BRGIRQID   | component | dir | meaning      | source
  23  * -----------------------------------------------------
  24  *     0      | USB-DMA   | ... | xfer done    | DMABRGI1
  25  *     1      | USB-UAE   | ... | USB addr err.| DMABRGI0
  26  *     2      | HAC0/SSI0 | play| all done     | DMABRGI1
  27  *     3      | HAC0/SSI0 | play| half done    | DMABRGI2
  28  *     4      | HAC0/SSI0 | rec | all done     | DMABRGI1
  29  *     5      | HAC0/SSI0 | rec | half done    | DMABRGI2
  30  *     6      | HAC1/SSI1 | play| all done     | DMABRGI1
  31  *     7      | HAC1/SSI1 | play| half done    | DMABRGI2
  32  *     8      | HAC1/SSI1 | rec | all done     | DMABRGI1
  33  *     9      | HAC1/SSI1 | rec | half done    | DMABRGI2
  34  *
  35  * all can be enabled/disabled in the DMABRGCR register,
  36  * as well as checked if they occurred.
  37  *
  38  * DMABRGI0 services  USB  DMA  Address  errors,  but it still must be
  39  * enabled/acked in the DMABRGCR register.  USB-DMA complete indicator
  40  * is grouped together with the audio buffer end indicators, too bad...
  41  *
  42  * DMABRGCR:    Bits 31-24: audio-dma ENABLE flags,
  43  *              Bits 23-16: audio-dma STATUS flags,
  44  *              Bits  9-8:  USB error/xfer ENABLE,
  45  *              Bits  1-0:  USB error/xfer STATUS.
  46  *      Ack an IRQ by writing 0 to the STATUS flag.
  47  *      Mask IRQ by writing 0 to ENABLE flag.
  48  *
  49  * Usage is almost like with any other IRQ:
  50  *  dmabrg_request_irq(BRGIRQID, handler, data)
  51  *  dmabrg_free_irq(BRGIRQID)
  52  *
  53  * handler prototype:  void brgirqhandler(void *data)
  54  */
  55
  56 #define DMARSRA         0xfe090000
  57 #define DMAOR           0xffa00040
  58 #define DMACHCR0        0xffa0000c
  59 #define DMABRGCR        0xfe3c0000
  60
  61 #define DMAOR_BRG       0x0000c000
  62 #define DMAOR_DMEN      0x00000001
  63
  64 #define DMABRGI0        68
  65 #define DMABRGI1        69
  66 #define DMABRGI2        70
  67
  68 struct dmabrg_handler {
  69         void (*handler)(void *);
  70         void *data;
  71 } *dmabrg_handlers;
  72
  73 static inline void dmabrg_call_handler(int i)
  74 {
  75         dmabrg_handlers[i].handler(dmabrg_handlers[i].data);
  76 }
  77
  78 /*
  79  * main DMABRG irq handler. It acks irqs and then
  80  * handles every set and unmasked bit sequentially.
  81  * No locking and no validity checks; it should be
  82  * as fast as possible (audio!)
  83  */
  84 static irqreturn_t dmabrg_irq(int irq, void *data)
  85 {
  86         unsigned long dcr;
  87         unsigned int i;
  88
  89         dcr = __raw_readl(DMABRGCR);
  90         __raw_writel(dcr & ~0x00ff0003, DMABRGCR);      /* ack all */
  91         dcr &= dcr >> 8;        /* ignore masked */
  92
  93         /* USB stuff, get it out of the way first */
  94         if (dcr & 1)
  95                 dmabrg_call_handler(DMABRGIRQ_USBDMA);
  96         if (dcr & 2)
  97                 dmabrg_call_handler(DMABRGIRQ_USBDMAERR);
  98
  99         /* Audio */
 100         dcr >>= 16;
 101         while (dcr) {
 102                 i = __ffs(dcr);
 103                 dcr &= dcr - 1;
 104                 dmabrg_call_handler(i + DMABRGIRQ_A0TXF);
 105         }
 106         return IRQ_HANDLED;
 107 }
 108
 109 static void dmabrg_disable_irq(unsigned int dmairq)
 110 {
 111         unsigned long dcr;
 112         dcr = __raw_readl(DMABRGCR);
 113         dcr &= ~(1 << ((dmairq > 1) ? dmairq + 22 : dmairq + 8));
 114         __raw_writel(dcr, DMABRGCR);
 115 }
 116
 117 static void dmabrg_enable_irq(unsigned int dmairq)
 118 {
 119         unsigned long dcr;
 120         dcr = __raw_readl(DMABRGCR);
 121         dcr |= (1 << ((dmairq > 1) ? dmairq + 22 : dmairq + 8));
 122         __raw_writel(dcr, DMABRGCR);
 123 }
 124
 125 int dmabrg_request_irq(unsigned int dmairq, void(*handler)(void*),
 126                        void *data)
 127 {
 128         if ((dmairq > 9) || !handler)
 129                 return -ENOENT;
 130         if (dmabrg_handlers[dmairq].handler)
 131                 return -EBUSY;
 132
 133         dmabrg_handlers[dmairq].handler = handler;
 134         dmabrg_handlers[dmairq].data = data;
 135
 136         dmabrg_enable_irq(dmairq);
 137         return 0;
 138 }
 139 EXPORT_SYMBOL_GPL(dmabrg_request_irq);
 140
 141 void dmabrg_free_irq(unsigned int dmairq)
 142 {
 143         if (likely(dmairq < 10)) {
 144                 dmabrg_disable_irq(dmairq);
 145                 dmabrg_handlers[dmairq].handler = NULL;
 146                 dmabrg_handlers[dmairq].data = NULL;
 147         }
 148 }
 149 EXPORT_SYMBOL_GPL(dmabrg_free_irq);
 150
 151 static int __init dmabrg_init(void)
 152 {
 153         unsigned long or;
 154         int ret;
 155
 156         dmabrg_handlers = kcalloc(10, sizeof(struct dmabrg_handler),
 157                                   GFP_KERNEL);
 158         if (!dmabrg_handlers)
 159                 return -ENOMEM;
 160
 161 #ifdef CONFIG_SH_DMA
 162         /* request DMAC channel 0 before anyone else can get it */
 163         ret = request_dma(0, "DMAC 0 (DMABRG)");
 164         if (ret < 0)
 165                 printk(KERN_INFO "DMABRG: DMAC ch0 not reserved!\n");
 166 #endif
 167
 168         __raw_writel(0, DMABRGCR);
 169         __raw_writel(0, DMACHCR0);
 170         __raw_writel(0x94000000, DMARSRA);      /* enable DMABRG in DMAC 0 */
 171
 172         /* enable DMABRG mode, enable the DMAC */
 173         or = __raw_readl(DMAOR);
 174         __raw_writel(or | DMAOR_BRG | DMAOR_DMEN, DMAOR);
 175
 176         ret = request_irq(DMABRGI0, dmabrg_irq, 0,
 177                         "DMABRG USB address error", NULL);
 178         if (ret)
 179                 goto out0;
 180
 181         ret = request_irq(DMABRGI1, dmabrg_irq, 0,
 182                         "DMABRG Transfer End", NULL);
 183         if (ret)
 184                 goto out1;
 185
 186         ret = request_irq(DMABRGI2, dmabrg_irq, 0,
 187                         "DMABRG Transfer Half", NULL);
 188         if (ret == 0)
 189                 return ret;
 190
 191         free_irq(DMABRGI1, NULL);
 192 out1:   free_irq(DMABRGI0, NULL);
 193 out0:   kfree(dmabrg_handlers);
 194         return ret;
 195 }
 196 subsys_initcall(dmabrg_init);