linux/drivers/media/pci/pt3/pt3_dma.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Earthsoft PT3 driver
   4 *
   5 * Copyright (C) 2014 Akihiro Tsukada <tskd08@gmail.com>
   6 */
   7#include <linux/dma-mapping.h>
   8#include <linux/kernel.h>
   9#include <linux/pci.h>
  10
  11#include "pt3.h"
  12
  13#define PT3_ACCESS_UNIT (TS_PACKET_SZ * 128)
  14#define PT3_BUF_CANARY  (0x74)
  15
  16static u32 get_dma_base(int idx)
  17{
  18        int i;
  19
  20        i = (idx == 1 || idx == 2) ? 3 - idx : idx;
  21        return REG_DMA_BASE + 0x18 * i;
  22}
  23
  24int pt3_stop_dma(struct pt3_adapter *adap)
  25{
  26        struct pt3_board *pt3 = adap->dvb_adap.priv;
  27        u32 base;
  28        u32 stat;
  29        int retry;
  30
  31        base = get_dma_base(adap->adap_idx);
  32        stat = ioread32(pt3->regs[0] + base + OFST_STATUS);
  33        if (!(stat & 0x01))
  34                return 0;
  35
  36        iowrite32(0x02, pt3->regs[0] + base + OFST_DMA_CTL);
  37        for (retry = 0; retry < 5; retry++) {
  38                stat = ioread32(pt3->regs[0] + base + OFST_STATUS);
  39                if (!(stat & 0x01))
  40                        return 0;
  41                msleep(50);
  42        }
  43        return -EIO;
  44}
  45
  46int pt3_start_dma(struct pt3_adapter *adap)
  47{
  48        struct pt3_board *pt3 = adap->dvb_adap.priv;
  49        u32 base = get_dma_base(adap->adap_idx);
  50
  51        iowrite32(0x02, pt3->regs[0] + base + OFST_DMA_CTL);
  52        iowrite32(lower_32_bits(adap->desc_buf[0].b_addr),
  53                        pt3->regs[0] + base + OFST_DMA_DESC_L);
  54        iowrite32(upper_32_bits(adap->desc_buf[0].b_addr),
  55                        pt3->regs[0] + base + OFST_DMA_DESC_H);
  56        iowrite32(0x01, pt3->regs[0] + base + OFST_DMA_CTL);
  57        return 0;
  58}
  59
  60
  61static u8 *next_unit(struct pt3_adapter *adap, int *idx, int *ofs)
  62{
  63        *ofs += PT3_ACCESS_UNIT;
  64        if (*ofs >= DATA_BUF_SZ) {
  65                *ofs -= DATA_BUF_SZ;
  66                (*idx)++;
  67                if (*idx == adap->num_bufs)
  68                        *idx = 0;
  69        }
  70        return &adap->buffer[*idx].data[*ofs];
  71}
  72
  73int pt3_proc_dma(struct pt3_adapter *adap)
  74{
  75        int idx, ofs;
  76
  77        idx = adap->buf_idx;
  78        ofs = adap->buf_ofs;
  79
  80        if (adap->buffer[idx].data[ofs] == PT3_BUF_CANARY)
  81                return 0;
  82
  83        while (*next_unit(adap, &idx, &ofs) != PT3_BUF_CANARY) {
  84                u8 *p;
  85
  86                p = &adap->buffer[adap->buf_idx].data[adap->buf_ofs];
  87                if (adap->num_discard > 0)
  88                        adap->num_discard--;
  89                else if (adap->buf_ofs + PT3_ACCESS_UNIT > DATA_BUF_SZ) {
  90                        dvb_dmx_swfilter_packets(&adap->demux, p,
  91                                (DATA_BUF_SZ - adap->buf_ofs) / TS_PACKET_SZ);
  92                        dvb_dmx_swfilter_packets(&adap->demux,
  93                                adap->buffer[idx].data, ofs / TS_PACKET_SZ);
  94                } else
  95                        dvb_dmx_swfilter_packets(&adap->demux, p,
  96                                PT3_ACCESS_UNIT / TS_PACKET_SZ);
  97
  98                *p = PT3_BUF_CANARY;
  99                adap->buf_idx = idx;
 100                adap->buf_ofs = ofs;
 101        }
 102        return 0;
 103}
 104
 105void pt3_init_dmabuf(struct pt3_adapter *adap)
 106{
 107        int idx, ofs;
 108        u8 *p;
 109
 110        idx = 0;
 111        ofs = 0;
 112        p = adap->buffer[0].data;
 113        /* mark the whole buffers as "not written yet" */
 114        while (idx < adap->num_bufs) {
 115                p[ofs] = PT3_BUF_CANARY;
 116                ofs += PT3_ACCESS_UNIT;
 117                if (ofs >= DATA_BUF_SZ) {
 118                        ofs -= DATA_BUF_SZ;
 119                        idx++;
 120                        p = adap->buffer[idx].data;
 121                }
 122        }
 123        adap->buf_idx = 0;
 124        adap->buf_ofs = 0;
 125}
 126
 127void pt3_free_dmabuf(struct pt3_adapter *adap)
 128{
 129        struct pt3_board *pt3;
 130        int i;
 131
 132        pt3 = adap->dvb_adap.priv;
 133        for (i = 0; i < adap->num_bufs; i++)
 134                dma_free_coherent(&pt3->pdev->dev, DATA_BUF_SZ,
 135                        adap->buffer[i].data, adap->buffer[i].b_addr);
 136        adap->num_bufs = 0;
 137
 138        for (i = 0; i < adap->num_desc_bufs; i++)
 139                dma_free_coherent(&pt3->pdev->dev, PAGE_SIZE,
 140                        adap->desc_buf[i].descs, adap->desc_buf[i].b_addr);
 141        adap->num_desc_bufs = 0;
 142}
 143
 144
 145int pt3_alloc_dmabuf(struct pt3_adapter *adap)
 146{
 147        struct pt3_board *pt3;
 148        void *p;
 149        int i, j;
 150        int idx, ofs;
 151        int num_desc_bufs;
 152        dma_addr_t data_addr, desc_addr;
 153        struct xfer_desc *d;
 154
 155        pt3 = adap->dvb_adap.priv;
 156        adap->num_bufs = 0;
 157        adap->num_desc_bufs = 0;
 158        for (i = 0; i < pt3->num_bufs; i++) {
 159                p = dma_alloc_coherent(&pt3->pdev->dev, DATA_BUF_SZ,
 160                                        &adap->buffer[i].b_addr, GFP_KERNEL);
 161                if (p == NULL)
 162                        goto failed;
 163                adap->buffer[i].data = p;
 164                adap->num_bufs++;
 165        }
 166        pt3_init_dmabuf(adap);
 167
 168        /* build circular-linked pointers (xfer_desc) to the data buffers*/
 169        idx = 0;
 170        ofs = 0;
 171        num_desc_bufs =
 172                DIV_ROUND_UP(adap->num_bufs * DATA_BUF_XFERS, DESCS_IN_PAGE);
 173        for (i = 0; i < num_desc_bufs; i++) {
 174                p = dma_alloc_coherent(&pt3->pdev->dev, PAGE_SIZE,
 175                                        &desc_addr, GFP_KERNEL);
 176                if (p == NULL)
 177                        goto failed;
 178                adap->num_desc_bufs++;
 179                adap->desc_buf[i].descs = p;
 180                adap->desc_buf[i].b_addr = desc_addr;
 181
 182                if (i > 0) {
 183                        d = &adap->desc_buf[i - 1].descs[DESCS_IN_PAGE - 1];
 184                        d->next_l = lower_32_bits(desc_addr);
 185                        d->next_h = upper_32_bits(desc_addr);
 186                }
 187                for (j = 0; j < DESCS_IN_PAGE; j++) {
 188                        data_addr = adap->buffer[idx].b_addr + ofs;
 189                        d = &adap->desc_buf[i].descs[j];
 190                        d->addr_l = lower_32_bits(data_addr);
 191                        d->addr_h = upper_32_bits(data_addr);
 192                        d->size = DATA_XFER_SZ;
 193
 194                        desc_addr += sizeof(struct xfer_desc);
 195                        d->next_l = lower_32_bits(desc_addr);
 196                        d->next_h = upper_32_bits(desc_addr);
 197
 198                        ofs += DATA_XFER_SZ;
 199                        if (ofs >= DATA_BUF_SZ) {
 200                                ofs -= DATA_BUF_SZ;
 201                                idx++;
 202                                if (idx >= adap->num_bufs) {
 203                                        desc_addr = adap->desc_buf[0].b_addr;
 204                                        d->next_l = lower_32_bits(desc_addr);
 205                                        d->next_h = upper_32_bits(desc_addr);
 206                                        return 0;
 207                                }
 208                        }
 209                }
 210        }
 211        return 0;
 212
 213failed:
 214        pt3_free_dmabuf(adap);
 215        return -ENOMEM;
 216}
 217
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