powerpc/espi: remove 80us delay to improve transfer performance

Replace 80 mircoseconds delay with polling flag ESPI_EV_TXE.

Signed-off-by: Hou Zhiqiang <B48286@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>

diff --git a/drivers/spi/fsl_espi.c b/drivers/spi/fsl_espi.c
index 7c845827627bc2a276e326f7119fab2c485fffc9..ae0fe58f2c06400e2cebfbd3b9bc680354ae99be 100644 (file)
--- 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));