u8 bits_per_word;
u16 clk_div; /* baud rate divider */
u32 speed_hz; /* baud rate */
- int (*write)(struct dw_spi *dws);
- int (*read)(struct dw_spi *dws);
void (*cs_control)(u32 command);
};
}
#endif /* CONFIG_DEBUG_FS */
-static void wait_till_not_busy(struct dw_spi *dws)
+/* Return the max entries we can fill into tx fifo */
+static inline u32 tx_max(struct dw_spi *dws)
{
- unsigned long end = jiffies + 1 + usecs_to_jiffies(5000);
+ u32 tx_left, tx_room, rxtx_gap;
- while (time_before(jiffies, end)) {
- if (!(dw_readw(dws, sr) & SR_BUSY))
- return;
- cpu_relax();
- }
- dev_err(&dws->master->dev,
- "DW SPI: Status keeps busy for 5000us after a read/write!\n");
-}
-
-static void flush(struct dw_spi *dws)
-{
- while (dw_readw(dws, sr) & SR_RF_NOT_EMPT) {
- dw_readw(dws, dr);
- cpu_relax();
- }
-
- wait_till_not_busy(dws);
-}
-
-static int null_writer(struct dw_spi *dws)
-{
- u8 n_bytes = dws->n_bytes;
+ tx_left = (dws->tx_end - dws->tx) / dws->n_bytes;
+ tx_room = dws->fifo_len - dw_readw(dws, txflr);
- if (!(dw_readw(dws, sr) & SR_TF_NOT_FULL)
- || (dws->tx == dws->tx_end))
- return 0;
- dw_writew(dws, dr, 0);
- dws->tx += n_bytes;
+ /*
+ * Another concern is about the tx/rx mismatch, we
+ * though to use (dws->fifo_len - rxflr - txflr) as
+ * one maximum value for tx, but it doesn't cover the
+ * data which is out of tx/rx fifo and inside the
+ * shift registers. So a control from sw point of
+ * view is taken.
+ */
+ rxtx_gap = ((dws->rx_end - dws->rx) - (dws->tx_end - dws->tx))
+ / dws->n_bytes;
- wait_till_not_busy(dws);
- return 1;
+ return min3(tx_left, tx_room, (u32) (dws->fifo_len - rxtx_gap));
}
-static int null_reader(struct dw_spi *dws)
+/* Return the max entries we should read out of rx fifo */
+static inline u32 rx_max(struct dw_spi *dws)
{
- u8 n_bytes = dws->n_bytes;
+ u32 rx_left = (dws->rx_end - dws->rx) / dws->n_bytes;
- while ((dw_readw(dws, sr) & SR_RF_NOT_EMPT)
- && (dws->rx < dws->rx_end)) {
- dw_readw(dws, dr);
- dws->rx += n_bytes;
- }
- wait_till_not_busy(dws);
- return dws->rx == dws->rx_end;
+ return min(rx_left, (u32)dw_readw(dws, rxflr));
}
-static int u8_writer(struct dw_spi *dws)
+static void dw_writer(struct dw_spi *dws)
{
- if (!(dw_readw(dws, sr) & SR_TF_NOT_FULL)
- || (dws->tx == dws->tx_end))
- return 0;
+ u32 max = tx_max(dws);
+ u16 txw = 0;
- dw_writew(dws, dr, *(u8 *)(dws->tx));
- ++dws->tx;
-
- wait_till_not_busy(dws);
- return 1;
-}
-
-static int u8_reader(struct dw_spi *dws)
-{
- while ((dw_readw(dws, sr) & SR_RF_NOT_EMPT)
- && (dws->rx < dws->rx_end)) {
- *(u8 *)(dws->rx) = dw_readw(dws, dr);
- ++dws->rx;
+ while (max--) {
+ /* Set the tx word if the transfer's original "tx" is not null */
+ if (dws->tx_end - dws->len) {
+ if (dws->n_bytes == 1)
+ txw = *(u8 *)(dws->tx);
+ else
+ txw = *(u16 *)(dws->tx);
+ }
+ dw_writew(dws, dr, txw);
+ dws->tx += dws->n_bytes;
}
-
- wait_till_not_busy(dws);
- return dws->rx == dws->rx_end;
}
-static int u16_writer(struct dw_spi *dws)
+static void dw_reader(struct dw_spi *dws)
{
- if (!(dw_readw(dws, sr) & SR_TF_NOT_FULL)
- || (dws->tx == dws->tx_end))
- return 0;
+ u32 max = rx_max(dws);
+ u16 rxw;
- dw_writew(dws, dr, *(u16 *)(dws->tx));
- dws->tx += 2;
-
- wait_till_not_busy(dws);
- return 1;
-}
-
-static int u16_reader(struct dw_spi *dws)
-{
- u16 temp;
-
- while ((dw_readw(dws, sr) & SR_RF_NOT_EMPT)
- && (dws->rx < dws->rx_end)) {
- temp = dw_readw(dws, dr);
- *(u16 *)(dws->rx) = temp;
- dws->rx += 2;
+ while (max--) {
+ rxw = dw_readw(dws, dr);
+ /* Care rx only if the transfer's original "rx" is not null */
+ if (dws->rx_end - dws->len) {
+ if (dws->n_bytes == 1)
+ *(u8 *)(dws->rx) = rxw;
+ else
+ *(u16 *)(dws->rx) = rxw;
+ }
+ dws->rx += dws->n_bytes;
}
-
- wait_till_not_busy(dws);
- return dws->rx == dws->rx_end;
}
static void *next_transfer(struct dw_spi *dws)
static void int_error_stop(struct dw_spi *dws, const char *msg)
{
- /* Stop and reset hw */
- flush(dws);
+ /* Stop the hw */
spi_enable_chip(dws, 0);
dev_err(&dws->master->dev, "%s\n", msg);
static irqreturn_t interrupt_transfer(struct dw_spi *dws)
{
- u16 irq_status, irq_mask = 0x3f;
- u32 int_level = dws->fifo_len / 2;
- u32 left;
+ u16 irq_status = dw_readw(dws, isr);
- irq_status = dw_readw(dws, isr) & irq_mask;
/* Error handling */
if (irq_status & (SPI_INT_TXOI | SPI_INT_RXOI | SPI_INT_RXUI)) {
dw_readw(dws, txoicr);
dw_readw(dws, rxoicr);
dw_readw(dws, rxuicr);
- int_error_stop(dws, "interrupt_transfer: fifo overrun");
+ int_error_stop(dws, "interrupt_transfer: fifo overrun/underrun");
return IRQ_HANDLED;
}
+ dw_reader(dws);
+ if (dws->rx_end == dws->rx) {
+ spi_mask_intr(dws, SPI_INT_TXEI);
+ dw_spi_xfer_done(dws);
+ return IRQ_HANDLED;
+ }
if (irq_status & SPI_INT_TXEI) {
spi_mask_intr(dws, SPI_INT_TXEI);
-
- left = (dws->tx_end - dws->tx) / dws->n_bytes;
- left = (left > int_level) ? int_level : left;
-
- while (left--)
- dws->write(dws);
- dws->read(dws);
-
- /* Re-enable the IRQ if there is still data left to tx */
- if (dws->tx_end > dws->tx)
- spi_umask_intr(dws, SPI_INT_TXEI);
- else
- dw_spi_xfer_done(dws);
+ dw_writer(dws);
+ /* Enable TX irq always, it will be disabled when RX finished */
+ spi_umask_intr(dws, SPI_INT_TXEI);
}
return IRQ_HANDLED;
static irqreturn_t dw_spi_irq(int irq, void *dev_id)
{
struct dw_spi *dws = dev_id;
- u16 irq_status, irq_mask = 0x3f;
+ u16 irq_status = dw_readw(dws, isr) & 0x3f;
- irq_status = dw_readw(dws, isr) & irq_mask;
if (!irq_status)
return IRQ_NONE;
if (!dws->cur_msg) {
spi_mask_intr(dws, SPI_INT_TXEI);
- /* Never fail */
return IRQ_HANDLED;
}
/* Must be called inside pump_transfers() */
static void poll_transfer(struct dw_spi *dws)
{
- while (dws->write(dws))
- dws->read(dws);
- /*
- * There is a possibility that the last word of a transaction
- * will be lost if data is not ready. Re-read to solve this issue.
- */
- dws->read(dws);
+ do {
+ dw_writer(dws);
+ dw_reader(dws);
+ cpu_relax();
+ } while (dws->rx_end > dws->rx);
dw_spi_xfer_done(dws);
}
dws->tx_end = dws->tx + transfer->len;
dws->rx = transfer->rx_buf;
dws->rx_end = dws->rx + transfer->len;
- dws->write = dws->tx ? chip->write : null_writer;
- dws->read = dws->rx ? chip->read : null_reader;
dws->cs_change = transfer->cs_change;
dws->len = dws->cur_transfer->len;
if (chip != dws->prev_chip)
switch (bits) {
case 8:
- dws->n_bytes = 1;
- dws->dma_width = 1;
- dws->read = (dws->read != null_reader) ?
- u8_reader : null_reader;
- dws->write = (dws->write != null_writer) ?
- u8_writer : null_writer;
- break;
case 16:
- dws->n_bytes = 2;
- dws->dma_width = 2;
- dws->read = (dws->read != null_reader) ?
- u16_reader : null_reader;
- dws->write = (dws->write != null_writer) ?
- u16_writer : null_writer;
+ dws->n_bytes = dws->dma_width = bits >> 3;
break;
default:
printk(KERN_ERR "MRST SPI0: unsupported bits:"
txint_level = dws->fifo_len / 2;
txint_level = (templen > txint_level) ? txint_level : templen;
- imask |= SPI_INT_TXEI;
+ imask |= SPI_INT_TXEI | SPI_INT_TXOI | SPI_INT_RXUI | SPI_INT_RXOI;
dws->transfer_handler = interrupt_transfer;
}
if (spi->bits_per_word <= 8) {
chip->n_bytes = 1;
chip->dma_width = 1;
- chip->read = u8_reader;
- chip->write = u8_writer;
} else if (spi->bits_per_word <= 16) {
chip->n_bytes = 2;
chip->dma_width = 2;
- chip->read = u16_reader;
- chip->write = u16_writer;
} else {
/* Never take >16b case for MRST SPIC */
dev_err(&spi->dev, "invalid wordsize\n");
spi_enable_chip(dws, 0);
spi_mask_intr(dws, 0xff);
spi_enable_chip(dws, 1);
- flush(dws);
/*
* Try to detect the FIFO depth if not set by interface driver,
projects / GitHub / mt8127 / android_kernel_alcatel_ttab.git / commitdiff