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ASoC: rt5677: Allow arbitrary block read/write via SPI
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Added rt5677_spi_read() and refactored rt5677_spi_write() so that
an arbitrary block in the DSP address space can be read/written
via SPI. For example, this allows us to load an ELF DSP firmware
with sparse sections, and stream audio samples from DSP ring buffer.

Signed-off-by: Ben Zhang <benzh@chromium.org>
Acked-by: Oder Chiou <oder_chiou@realtek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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Ben Zhang authored and Mark Brown committed Aug 25, 2015
1 parent f8163c8 commit 7d4d443
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Showing 3 changed files with 178 additions and 67 deletions.
233 changes: 173 additions & 60 deletions sound/soc/codecs/rt5677-spi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -31,84 +31,197 @@

#include "rt5677-spi.h"

#define RT5677_SPI_BURST_LEN 240
#define RT5677_SPI_HEADER 5
#define RT5677_SPI_FREQ 6000000

/* The AddressPhase and DataPhase of SPI commands are MSB first on the wire.
* DataPhase word size of 16-bit commands is 2 bytes.
* DataPhase word size of 32-bit commands is 4 bytes.
* DataPhase word size of burst commands is 8 bytes.
* The DSP CPU is little-endian.
*/
#define RT5677_SPI_WRITE_BURST 0x5
#define RT5677_SPI_READ_BURST 0x4
#define RT5677_SPI_WRITE_32 0x3
#define RT5677_SPI_READ_32 0x2
#define RT5677_SPI_WRITE_16 0x1
#define RT5677_SPI_READ_16 0x0

static struct spi_device *g_spi;
static DEFINE_MUTEX(spi_mutex);

/**
* rt5677_spi_write - Write data to SPI.
* @txbuf: Data Buffer for writing.
* @len: Data length.
/* Select a suitable transfer command for the next transfer to ensure
* the transfer address is always naturally aligned while minimizing
* the total number of transfers required.
*
* 3 transfer commands are available:
* RT5677_SPI_READ/WRITE_16: Transfer 2 bytes
* RT5677_SPI_READ/WRITE_32: Transfer 4 bytes
* RT5677_SPI_READ/WRITE_BURST: Transfer any multiples of 8 bytes
*
* For example, reading 260 bytes at 0x60030002 uses the following commands:
* 0x60030002 RT5677_SPI_READ_16 2 bytes
* 0x60030004 RT5677_SPI_READ_32 4 bytes
* 0x60030008 RT5677_SPI_READ_BURST 240 bytes
* 0x600300F8 RT5677_SPI_READ_BURST 8 bytes
* 0x60030100 RT5677_SPI_READ_32 4 bytes
* 0x60030104 RT5677_SPI_READ_16 2 bytes
*
* Input:
* @read: true for read commands; false for write commands
* @align: alignment of the next transfer address
* @remain: number of bytes remaining to transfer
*
* Returns true for success.
* Output:
* @len: number of bytes to transfer with the selected command
* Returns the selected command
*/
int rt5677_spi_write(u8 *txbuf, size_t len)
static u8 rt5677_spi_select_cmd(bool read, u32 align, u32 remain, u32 *len)
{
int status;

status = spi_write(g_spi, txbuf, len);

if (status)
dev_err(&g_spi->dev, "rt5677_spi_write error %d\n", status);

return status;
u8 cmd;

if (align == 2 || align == 6 || remain == 2) {
cmd = RT5677_SPI_READ_16;
*len = 2;
} else if (align == 4 || remain <= 6) {
cmd = RT5677_SPI_READ_32;
*len = 4;
} else {
cmd = RT5677_SPI_READ_BURST;
*len = min_t(u32, remain & ~7, RT5677_SPI_BURST_LEN);
}
return read ? cmd : cmd + 1;
}
EXPORT_SYMBOL_GPL(rt5677_spi_write);

/**
* rt5677_spi_burst_write - Write data to SPI by rt5677 dsp memory address.
* @addr: Start address.
* @txbuf: Data Buffer for writng.
* @len: Data length, it must be a multiple of 8.
*
*
* Returns true for success.
/* Copy dstlen bytes from src to dst, while reversing byte order for each word.
* If srclen < dstlen, zeros are padded.
*/
int rt5677_spi_burst_write(u32 addr, const struct firmware *fw)
static void rt5677_spi_reverse(u8 *dst, u32 dstlen, const u8 *src, u32 srclen)
{
u8 spi_cmd = RT5677_SPI_CMD_BURST_WRITE;
u8 *write_buf;
unsigned int i, end, offset = 0;

write_buf = kmalloc(RT5677_SPI_BUF_LEN + 6, GFP_KERNEL);

if (write_buf == NULL)
return -ENOMEM;

while (offset < fw->size) {
if (offset + RT5677_SPI_BUF_LEN <= fw->size)
end = RT5677_SPI_BUF_LEN;
else
end = fw->size % RT5677_SPI_BUF_LEN;

write_buf[0] = spi_cmd;
write_buf[1] = ((addr + offset) & 0xff000000) >> 24;
write_buf[2] = ((addr + offset) & 0x00ff0000) >> 16;
write_buf[3] = ((addr + offset) & 0x0000ff00) >> 8;
write_buf[4] = ((addr + offset) & 0x000000ff) >> 0;

for (i = 0; i < end; i += 8) {
write_buf[i + 12] = fw->data[offset + i + 0];
write_buf[i + 11] = fw->data[offset + i + 1];
write_buf[i + 10] = fw->data[offset + i + 2];
write_buf[i + 9] = fw->data[offset + i + 3];
write_buf[i + 8] = fw->data[offset + i + 4];
write_buf[i + 7] = fw->data[offset + i + 5];
write_buf[i + 6] = fw->data[offset + i + 6];
write_buf[i + 5] = fw->data[offset + i + 7];
u32 w, i, si;
u32 word_size = min_t(u32, dstlen, 8);

for (w = 0; w < dstlen; w += word_size) {
for (i = 0; i < word_size; i++) {
si = w + word_size - i - 1;
dst[w + i] = si < srclen ? src[si] : 0;
}
}
}

write_buf[end + 5] = spi_cmd;
/* Read DSP address space using SPI. addr and len have to be 2-byte aligned. */
int rt5677_spi_read(u32 addr, void *rxbuf, size_t len)
{
u32 offset;
int status = 0;
struct spi_transfer t[2];
struct spi_message m;
/* +4 bytes is for the DummyPhase following the AddressPhase */
u8 header[RT5677_SPI_HEADER + 4];
u8 body[RT5677_SPI_BURST_LEN];
u8 spi_cmd;
u8 *cb = rxbuf;

if (!g_spi)
return -ENODEV;

if ((addr & 1) || (len & 1)) {
dev_err(&g_spi->dev, "Bad read align 0x%x(%zu)\n", addr, len);
return -EACCES;
}

rt5677_spi_write(write_buf, end + 6);
memset(t, 0, sizeof(t));
t[0].tx_buf = header;
t[0].len = sizeof(header);
t[0].speed_hz = RT5677_SPI_FREQ;
t[1].rx_buf = body;
t[1].speed_hz = RT5677_SPI_FREQ;
spi_message_init_with_transfers(&m, t, ARRAY_SIZE(t));

for (offset = 0; offset < len; offset += t[1].len) {
spi_cmd = rt5677_spi_select_cmd(true, (addr + offset) & 7,
len - offset, &t[1].len);

/* Construct SPI message header */
header[0] = spi_cmd;
header[1] = ((addr + offset) & 0xff000000) >> 24;
header[2] = ((addr + offset) & 0x00ff0000) >> 16;
header[3] = ((addr + offset) & 0x0000ff00) >> 8;
header[4] = ((addr + offset) & 0x000000ff) >> 0;

mutex_lock(&spi_mutex);
status |= spi_sync(g_spi, &m);
mutex_unlock(&spi_mutex);

/* Copy data back to caller buffer */
rt5677_spi_reverse(cb + offset, t[1].len, body, t[1].len);
}
return status;
}
EXPORT_SYMBOL_GPL(rt5677_spi_read);

offset += RT5677_SPI_BUF_LEN;
/* Write DSP address space using SPI. addr has to be 2-byte aligned.
* If len is not 2-byte aligned, an extra byte of zero is written at the end
* as padding.
*/
int rt5677_spi_write(u32 addr, const void *txbuf, size_t len)
{
u32 offset, len_with_pad = len;
int status = 0;
struct spi_transfer t;
struct spi_message m;
/* +1 byte is for the DummyPhase following the DataPhase */
u8 buf[RT5677_SPI_HEADER + RT5677_SPI_BURST_LEN + 1];
u8 *body = buf + RT5677_SPI_HEADER;
u8 spi_cmd;
const u8 *cb = txbuf;

if (!g_spi)
return -ENODEV;

if (addr & 1) {
dev_err(&g_spi->dev, "Bad write align 0x%x(%zu)\n", addr, len);
return -EACCES;
}

kfree(write_buf);
if (len & 1)
len_with_pad = len + 1;

memset(&t, 0, sizeof(t));
t.tx_buf = buf;
t.speed_hz = RT5677_SPI_FREQ;
spi_message_init_with_transfers(&m, &t, 1);

for (offset = 0; offset < len_with_pad;) {
spi_cmd = rt5677_spi_select_cmd(false, (addr + offset) & 7,
len_with_pad - offset, &t.len);

/* Construct SPI message header */
buf[0] = spi_cmd;
buf[1] = ((addr + offset) & 0xff000000) >> 24;
buf[2] = ((addr + offset) & 0x00ff0000) >> 16;
buf[3] = ((addr + offset) & 0x0000ff00) >> 8;
buf[4] = ((addr + offset) & 0x000000ff) >> 0;

/* Fetch data from caller buffer */
rt5677_spi_reverse(body, t.len, cb + offset, len - offset);
offset += t.len;
t.len += RT5677_SPI_HEADER + 1;

mutex_lock(&spi_mutex);
status |= spi_sync(g_spi, &m);
mutex_unlock(&spi_mutex);
}
return status;
}
EXPORT_SYMBOL_GPL(rt5677_spi_write);

return 0;
int rt5677_spi_write_firmware(u32 addr, const struct firmware *fw)
{
return rt5677_spi_write(addr, fw->data, fw->size);
}
EXPORT_SYMBOL_GPL(rt5677_spi_burst_write);
EXPORT_SYMBOL_GPL(rt5677_spi_write_firmware);

static int rt5677_spi_probe(struct spi_device *spi)
{
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8 changes: 3 additions & 5 deletions sound/soc/codecs/rt5677-spi.h
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Expand Up @@ -12,10 +12,8 @@
#ifndef __RT5677_SPI_H__
#define __RT5677_SPI_H__

#define RT5677_SPI_BUF_LEN 240
#define RT5677_SPI_CMD_BURST_WRITE 0x05

int rt5677_spi_write(u8 *txbuf, size_t len);
int rt5677_spi_burst_write(u32 addr, const struct firmware *fw);
int rt5677_spi_read(u32 addr, void *rxbuf, size_t len);
int rt5677_spi_write(u32 addr, const void *txbuf, size_t len);
int rt5677_spi_write_firmware(u32 addr, const struct firmware *fw);

#endif /* __RT5677_SPI_H__ */
4 changes: 2 additions & 2 deletions sound/soc/codecs/rt5677.c
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Original file line number Diff line number Diff line change
Expand Up @@ -745,14 +745,14 @@ static int rt5677_set_dsp_vad(struct snd_soc_codec *codec, bool on)
ret = request_firmware(&rt5677->fw1, RT5677_FIRMWARE1,
codec->dev);
if (ret == 0) {
rt5677_spi_burst_write(0x50000000, rt5677->fw1);
rt5677_spi_write_firmware(0x50000000, rt5677->fw1);
release_firmware(rt5677->fw1);
}

ret = request_firmware(&rt5677->fw2, RT5677_FIRMWARE2,
codec->dev);
if (ret == 0) {
rt5677_spi_burst_write(0x60000000, rt5677->fw2);
rt5677_spi_write_firmware(0x60000000, rt5677->fw2);
release_firmware(rt5677->fw2);
}

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