wl1271: Implementation for SPI busy word checking
This patch adds implementation for checking for SPI busy words - i.e.
honoring a delay request from the WLAN chipset upon reading
registers/memory.
To optimized the average SPI ready by 32 bits, also configure the number
of busywords to one to disable the "fixed-busy-word" functionality.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Vidhya Govindan <vidhya.govindan@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/wl12xx/wl1271_spi.c b/drivers/net/wireless/wl12xx/wl1271_spi.c
index 4a12880..504991a 100644
--- a/drivers/net/wireless/wl12xx/wl1271_spi.c
+++ b/drivers/net/wireless/wl12xx/wl1271_spi.c
@@ -244,12 +244,75 @@
return 0;
}
+#define WL1271_BUSY_WORD_TIMEOUT 1000
+
+void wl1271_spi_read_busy(struct wl1271 *wl, void *buf, size_t len)
+{
+ struct spi_transfer t[1];
+ struct spi_message m;
+ u32 *busy_buf;
+ int num_busy_bytes = 0;
+
+ wl1271_info("spi read BUSY!");
+
+ /*
+ * Look for the non-busy word in the read buffer, and if found,
+ * read in the remaining data into the buffer.
+ */
+ busy_buf = (u32 *)buf;
+ for (; (u32)busy_buf < (u32)buf + len; busy_buf++) {
+ num_busy_bytes += sizeof(u32);
+ if (*busy_buf & 0x1) {
+ spi_message_init(&m);
+ memset(t, 0, sizeof(t));
+ memmove(buf, busy_buf, len - num_busy_bytes);
+ t[0].rx_buf = buf + (len - num_busy_bytes);
+ t[0].len = num_busy_bytes;
+ spi_message_add_tail(&t[0], &m);
+ spi_sync(wl->spi, &m);
+ return;
+ }
+ }
+
+ /*
+ * Read further busy words from SPI until a non-busy word is
+ * encountered, then read the data itself into the buffer.
+ */
+ wl1271_info("spi read BUSY-polling needed!");
+
+ num_busy_bytes = WL1271_BUSY_WORD_TIMEOUT;
+ busy_buf = wl->buffer_busyword;
+ while (num_busy_bytes) {
+ num_busy_bytes--;
+ spi_message_init(&m);
+ memset(t, 0, sizeof(t));
+ t[0].rx_buf = busy_buf;
+ t[0].len = sizeof(u32);
+ spi_message_add_tail(&t[0], &m);
+ spi_sync(wl->spi, &m);
+
+ if (*busy_buf & 0x1) {
+ spi_message_init(&m);
+ memset(t, 0, sizeof(t));
+ t[0].rx_buf = buf;
+ t[0].len = len;
+ spi_message_add_tail(&t[0], &m);
+ spi_sync(wl->spi, &m);
+ return;
+ }
+ }
+
+ /* The SPI bus is unresponsive, the read failed. */
+ memset(buf, 0, len);
+ wl1271_error("SPI read busy-word timeout!\n");
+}
+
void wl1271_spi_read(struct wl1271 *wl, int addr, void *buf,
size_t len, bool fixed)
{
struct spi_transfer t[3];
struct spi_message m;
- u8 *busy_buf;
+ u32 *busy_buf;
u32 *cmd;
cmd = &wl->buffer_cmd;
@@ -281,7 +344,9 @@
spi_sync(wl->spi, &m);
- /* FIXME: check busy words */
+ /* Check busy words */
+ if (!(busy_buf[WL1271_BUSY_WORD_CNT - 1] & 0x1))
+ wl1271_spi_read_busy(wl, buf, len);
wl1271_dump(DEBUG_SPI, "spi_read cmd -> ", cmd, sizeof(*cmd));
wl1271_dump(DEBUG_SPI, "spi_read buf <- ", buf, len);