pt3_dma.c

  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}