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wl1271: Handle large SPI transfers
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The HW supports up to 4095 bytes transfers via SPI. The SPI read & write
operations do not handle larger transfers, causing the HW to stall in such
cases.

Fix this by fragmenting large transfers into smaller chunks, and
transferring each one separately.

Signed-off-by: Ido Yariv <ido@wizery.com>
Tested-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
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Ido Yariv authored and Luciano Coelho committed Oct 5, 2010
1 parent 6583611 commit 5c57a90
Showing 1 changed file with 86 additions and 54 deletions.
140 changes: 86 additions & 54 deletions drivers/net/wireless/wl12xx/wl1271_spi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -63,6 +63,11 @@
((WL1271_BUSY_WORD_LEN - 4) / sizeof(u32))
#define HW_ACCESS_WSPI_INIT_CMD_MASK 0

/* HW limitation: maximum possible chunk size is 4095 bytes */
#define WSPI_MAX_CHUNK_SIZE 4092

#define WSPI_MAX_NUM_OF_CHUNKS (WL1271_AGGR_BUFFER_SIZE / WSPI_MAX_CHUNK_SIZE)

static inline struct spi_device *wl_to_spi(struct wl1271 *wl)
{
return wl->if_priv;
Expand Down Expand Up @@ -202,90 +207,117 @@ static int wl1271_spi_read_busy(struct wl1271 *wl)
static void wl1271_spi_raw_read(struct wl1271 *wl, int addr, void *buf,
size_t len, bool fixed)
{
struct spi_transfer t[3];
struct spi_transfer t[2];
struct spi_message m;
u32 *busy_buf;
u32 *cmd;
u32 chunk_len;

cmd = &wl->buffer_cmd;
busy_buf = wl->buffer_busyword;
while (len > 0) {
chunk_len = min((size_t)WSPI_MAX_CHUNK_SIZE, len);

*cmd = 0;
*cmd |= WSPI_CMD_READ;
*cmd |= (len << WSPI_CMD_BYTE_LENGTH_OFFSET) & WSPI_CMD_BYTE_LENGTH;
*cmd |= addr & WSPI_CMD_BYTE_ADDR;
cmd = &wl->buffer_cmd;
busy_buf = wl->buffer_busyword;

if (fixed)
*cmd |= WSPI_CMD_FIXED;
*cmd = 0;
*cmd |= WSPI_CMD_READ;
*cmd |= (chunk_len << WSPI_CMD_BYTE_LENGTH_OFFSET) &
WSPI_CMD_BYTE_LENGTH;
*cmd |= addr & WSPI_CMD_BYTE_ADDR;

spi_message_init(&m);
memset(t, 0, sizeof(t));
if (fixed)
*cmd |= WSPI_CMD_FIXED;

t[0].tx_buf = cmd;
t[0].len = 4;
t[0].cs_change = true;
spi_message_add_tail(&t[0], &m);
spi_message_init(&m);
memset(t, 0, sizeof(t));

/* Busy and non busy words read */
t[1].rx_buf = busy_buf;
t[1].len = WL1271_BUSY_WORD_LEN;
t[1].cs_change = true;
spi_message_add_tail(&t[1], &m);
t[0].tx_buf = cmd;
t[0].len = 4;
t[0].cs_change = true;
spi_message_add_tail(&t[0], &m);

spi_sync(wl_to_spi(wl), &m);
/* Busy and non busy words read */
t[1].rx_buf = busy_buf;
t[1].len = WL1271_BUSY_WORD_LEN;
t[1].cs_change = true;
spi_message_add_tail(&t[1], &m);

if (!(busy_buf[WL1271_BUSY_WORD_CNT - 1] & 0x1) &&
wl1271_spi_read_busy(wl)) {
memset(buf, 0, len);
return;
}
spi_sync(wl_to_spi(wl), &m);

spi_message_init(&m);
memset(t, 0, sizeof(t));
if (!(busy_buf[WL1271_BUSY_WORD_CNT - 1] & 0x1) &&
wl1271_spi_read_busy(wl)) {
memset(buf, 0, chunk_len);
return;
}

t[0].rx_buf = buf;
t[0].len = len;
t[0].cs_change = true;
spi_message_add_tail(&t[0], &m);
spi_message_init(&m);
memset(t, 0, sizeof(t));

spi_sync(wl_to_spi(wl), &m);
t[0].rx_buf = buf;
t[0].len = chunk_len;
t[0].cs_change = true;
spi_message_add_tail(&t[0], &m);

spi_sync(wl_to_spi(wl), &m);

wl1271_dump(DEBUG_SPI, "spi_read cmd -> ", cmd, sizeof(*cmd));
wl1271_dump(DEBUG_SPI, "spi_read buf <- ", buf, len);
wl1271_dump(DEBUG_SPI, "spi_read cmd -> ", cmd, sizeof(*cmd));
wl1271_dump(DEBUG_SPI, "spi_read buf <- ", buf, chunk_len);

if (!fixed)
addr += chunk_len;
buf += chunk_len;
len -= chunk_len;
}
}

static void wl1271_spi_raw_write(struct wl1271 *wl, int addr, void *buf,
size_t len, bool fixed)
{
struct spi_transfer t[2];
struct spi_transfer t[2 * WSPI_MAX_NUM_OF_CHUNKS];
struct spi_message m;
u32 commands[WSPI_MAX_NUM_OF_CHUNKS];
u32 *cmd;
u32 chunk_len;
int i;

cmd = &wl->buffer_cmd;

*cmd = 0;
*cmd |= WSPI_CMD_WRITE;
*cmd |= (len << WSPI_CMD_BYTE_LENGTH_OFFSET) & WSPI_CMD_BYTE_LENGTH;
*cmd |= addr & WSPI_CMD_BYTE_ADDR;

if (fixed)
*cmd |= WSPI_CMD_FIXED;
WARN_ON(len > WL1271_AGGR_BUFFER_SIZE);

spi_message_init(&m);
memset(t, 0, sizeof(t));

t[0].tx_buf = cmd;
t[0].len = sizeof(*cmd);
spi_message_add_tail(&t[0], &m);
cmd = &commands[0];
i = 0;
while (len > 0) {
chunk_len = min((size_t)WSPI_MAX_CHUNK_SIZE, len);

t[1].tx_buf = buf;
t[1].len = len;
spi_message_add_tail(&t[1], &m);
*cmd = 0;
*cmd |= WSPI_CMD_WRITE;
*cmd |= (chunk_len << WSPI_CMD_BYTE_LENGTH_OFFSET) &
WSPI_CMD_BYTE_LENGTH;
*cmd |= addr & WSPI_CMD_BYTE_ADDR;

spi_sync(wl_to_spi(wl), &m);
if (fixed)
*cmd |= WSPI_CMD_FIXED;

t[i].tx_buf = cmd;
t[i].len = sizeof(*cmd);
spi_message_add_tail(&t[i++], &m);

t[i].tx_buf = buf;
t[i].len = chunk_len;
spi_message_add_tail(&t[i++], &m);

wl1271_dump(DEBUG_SPI, "spi_write cmd -> ", cmd, sizeof(*cmd));
wl1271_dump(DEBUG_SPI, "spi_write buf -> ", buf, len);
wl1271_dump(DEBUG_SPI, "spi_write cmd -> ", cmd, sizeof(*cmd));
wl1271_dump(DEBUG_SPI, "spi_write buf -> ", buf, chunk_len);

if (!fixed)
addr += chunk_len;
buf += chunk_len;
len -= chunk_len;
cmd++;
}

spi_sync(wl_to_spi(wl), &m);
}

static irqreturn_t wl1271_irq(int irq, void *cookie)
Expand Down

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