[U-Boot] [PATCH] powerpc/espi: remove 80us delay to improve transfer performance
Hou Zhiqiang
B48286 at freescale.com
Wed May 21 04:25:10 CEST 2014
Replace 80 mircoseconds delay with polling flag ESPI_EV_TXE.
Signed-off-by: Hou Zhiqiang <B48286 at freescale.com>
---
drivers/spi/fsl_espi.c | 138 +++++++++++++++++++++++++++++++++++++------------
1 file changed, 106 insertions(+), 32 deletions(-)
diff --git a/drivers/spi/fsl_espi.c b/drivers/spi/fsl_espi.c
index 7c84582..ae0fe58 100644
--- a/drivers/spi/fsl_espi.c
+++ b/drivers/spi/fsl_espi.c
@@ -15,8 +15,10 @@
struct fsl_spi_slave {
struct spi_slave slave;
+ ccsr_espi_t *espi;
unsigned int div16;
unsigned int pm;
+ int tx_timeout;
unsigned int mode;
size_t cmd_len;
u8 cmd_buf[16];
@@ -25,11 +27,17 @@ struct fsl_spi_slave {
};
#define to_fsl_spi_slave(s) container_of(s, struct fsl_spi_slave, slave)
+#define US_PER_SECOND 1000000UL
#define ESPI_MAX_CS_NUM 4
+#define ESPI_FIFO_WIDTH_BIT 32
#define ESPI_EV_RNE (1 << 9)
#define ESPI_EV_TNF (1 << 8)
+#define ESPI_EV_DON (1 << 14)
+#define ESPI_EV_TXE (1 << 15)
+#define ESPI_EV_RFCNT_SHIFT 24
+#define ESPI_EV_RFCNT_MASK (0x3f << ESPI_EV_RFCNT_SHIFT)
#define ESPI_MODE_EN (1 << 31) /* Enable interface */
#define ESPI_MODE_TXTHR(x) ((x) << 8) /* Tx FIFO threshold */
@@ -61,6 +69,7 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
struct fsl_spi_slave *fsl;
sys_info_t sysinfo;
unsigned long spibrg = 0;
+ unsigned long spi_freq = 0;
unsigned char pm = 0;
if (!spi_cs_is_valid(bus, cs))
@@ -70,6 +79,7 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
if (!fsl)
return NULL;
+ fsl->espi = (void *)(CONFIG_SYS_MPC85xx_ESPI_ADDR);
fsl->mode = mode;
fsl->max_transfer_length = ESPI_MAX_DATA_TRANSFER_LEN;
@@ -91,6 +101,15 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
pm--;
fsl->pm = pm;
+ if (fsl->div16)
+ spi_freq = spibrg / ((pm + 1) * 2 * 16);
+ else
+ spi_freq = spibrg / ((pm + 1) * 2);
+
+ /* set tx_timeout to 10 times of one espi FIFO entry go out */
+ fsl->tx_timeout = DIV_ROUND_UP((US_PER_SECOND * ESPI_FIFO_WIDTH_BIT
+ * 10), spi_freq);
+
return &fsl->slave;
}
@@ -108,7 +127,7 @@ void spi_init(void)
int spi_claim_bus(struct spi_slave *slave)
{
struct fsl_spi_slave *fsl = to_fsl_spi_slave(slave);
- ccsr_espi_t *espi = (void *)(CONFIG_SYS_MPC85xx_ESPI_ADDR);
+ ccsr_espi_t *espi = fsl->espi;
unsigned char pm = fsl->pm;
unsigned int cs = slave->cs;
unsigned int mode = fsl->mode;
@@ -161,24 +180,86 @@ void spi_release_bus(struct spi_slave *slave)
}
+static void fsl_espi_tx(struct fsl_spi_slave *fsl, const void *dout)
+{
+ ccsr_espi_t *espi = fsl->espi;
+ unsigned int tmpdout, event;
+ int tmp_tx_timeout;
+
+ if (dout)
+ tmpdout = *(u32 *)dout;
+ else
+ tmpdout = 0;
+
+ out_be32(&espi->tx, tmpdout);
+ out_be32(&espi->event, ESPI_EV_TNF);
+ debug("***spi_xfer:...%08x written\n", tmpdout);
+
+ tmp_tx_timeout = fsl->tx_timeout;
+ /* Wait for eSPI transmit to go out */
+ while (tmp_tx_timeout--) {
+ event = in_be32(&espi->event);
+ if (event & ESPI_EV_DON || event & ESPI_EV_TXE) {
+ out_be32(&espi->event, ESPI_EV_TXE);
+ break;
+ }
+ udelay(1);
+ }
+
+ if (tmp_tx_timeout < 0)
+ debug("***spi_xfer:...Tx timeout! event = %08x\n", event);
+}
+
+static int fsl_espi_rx(struct fsl_spi_slave *fsl, void *din, unsigned int bytes)
+{
+ ccsr_espi_t *espi = fsl->espi;
+ unsigned int tmpdin, rx_times;
+ unsigned char *buf, *p_cursor;
+
+ if (bytes <= 0)
+ return 0;
+
+ rx_times = DIV_ROUND_UP(bytes, 4);
+ buf = (unsigned char *)malloc(4 * rx_times);
+ if (!buf) {
+ debug("SF: Failed to malloc memory.\n");
+ return -1;
+ }
+ p_cursor = buf;
+ while (rx_times--) {
+ tmpdin = in_be32(&espi->rx);
+ debug("***spi_xfer:...%08x readed\n", tmpdin);
+ *(u32 *)p_cursor = tmpdin;
+ p_cursor += 4;
+ }
+
+ if (din)
+ memcpy(din, buf, bytes);
+
+ free(buf);
+ out_be32(&espi->event, ESPI_EV_RNE);
+
+ return bytes;
+}
+
int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *data_out,
void *data_in, unsigned long flags)
{
struct fsl_spi_slave *fsl = to_fsl_spi_slave(slave);
- ccsr_espi_t *espi = (void *)(CONFIG_SYS_MPC85xx_ESPI_ADDR);
- unsigned int tmpdout, tmpdin, event;
+ ccsr_espi_t *espi = fsl->espi;
+ unsigned int event, rx_bytes;
const void *dout = NULL;
void *din = NULL;
int len = 0;
int num_blks, num_chunks, max_tran_len, tran_len;
int num_bytes;
- unsigned char *ch;
unsigned char *buffer = NULL;
size_t buf_len;
u8 *cmd_buf = fsl->cmd_buf;
size_t cmd_len = fsl->cmd_len;
size_t data_len = bitlen / 8;
size_t rx_offset = 0;
+ int rf_cnt;
max_tran_len = fsl->max_transfer_length;
switch (flags) {
@@ -217,9 +298,8 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *data_out,
break;
}
- debug("spi_xfer: slave %u:%u dout %08X(%p) din %08X(%p) len %u\n",
- slave->bus, slave->cs, *(uint *) dout,
- dout, *(uint *) din, din, len);
+ debug("spi_xfer: data_out %08X(%p) data_in %08X(%p) len %u\n",
+ *(uint *)data_out, data_out, *(uint *)data_in, data_in, len);
num_chunks = DIV_ROUND_UP(data_len, max_tran_len);
while (num_chunks--) {
@@ -235,41 +315,34 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *data_out,
/* Clear all eSPI events */
out_be32(&espi->event , 0xffffffff);
/* handle data in 32-bit chunks */
- while (num_blks--) {
-
+ while (num_blks) {
event = in_be32(&espi->event);
if (event & ESPI_EV_TNF) {
- tmpdout = *(u32 *)dout;
-
+ fsl_espi_tx(fsl, dout);
/* Set up the next iteration */
if (len > 4) {
len -= 4;
dout += 4;
}
-
- out_be32(&espi->tx, tmpdout);
- out_be32(&espi->event, ESPI_EV_TNF);
- debug("***spi_xfer:...%08x written\n", tmpdout);
}
- /* Wait for eSPI transmit to get out */
- udelay(80);
-
event = in_be32(&espi->event);
if (event & ESPI_EV_RNE) {
- tmpdin = in_be32(&espi->rx);
- if (num_blks == 0 && num_bytes != 0) {
- ch = (unsigned char *)&tmpdin;
- while (num_bytes--)
- *(unsigned char *)din++ = *ch++;
- } else {
- *(u32 *) din = tmpdin;
- din += 4;
+ rf_cnt = ((event & ESPI_EV_RFCNT_MASK)
+ >> ESPI_EV_RFCNT_SHIFT);
+ if (rf_cnt >= 4)
+ rx_bytes = 4;
+ else if (num_blks == 1 && rf_cnt == num_bytes)
+ rx_bytes = num_bytes;
+ else
+ continue;
+ if (fsl_espi_rx(fsl, din, rx_bytes)
+ == rx_bytes) {
+ num_blks--;
+ if (din)
+ din = (unsigned char *)din
+ + rx_bytes;
}
-
- out_be32(&espi->event, in_be32(&espi->event)
- | ESPI_EV_RNE);
- debug("***spi_xfer:...%08x readed\n", tmpdin);
}
}
if (data_in) {
@@ -295,7 +368,7 @@ int spi_cs_is_valid(unsigned int bus, unsigned int cs)
void spi_cs_activate(struct spi_slave *slave)
{
struct fsl_spi_slave *fsl = to_fsl_spi_slave(slave);
- ccsr_espi_t *espi = (void *)(CONFIG_SYS_MPC85xx_ESPI_ADDR);
+ ccsr_espi_t *espi = fsl->espi;
unsigned int com = 0;
size_t data_len = fsl->data_len;
@@ -307,7 +380,8 @@ void spi_cs_activate(struct spi_slave *slave)
void spi_cs_deactivate(struct spi_slave *slave)
{
- ccsr_espi_t *espi = (void *)(CONFIG_SYS_MPC85xx_ESPI_ADDR);
+ struct fsl_spi_slave *fsl = to_fsl_spi_slave(slave);
+ ccsr_espi_t *espi = fsl->espi;
/* clear the RXCNT and TXCNT */
out_be32(&espi->mode, in_be32(&espi->mode) & (~ESPI_MODE_EN));
--
1.8.5
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