These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / drivers / spi / spi-xilinx.c

diff --git a/kernel/drivers/spi/spi-xilinx.c b/kernel/drivers/spi/spi-xilinx.c
index a339c1e..3009121 100644 (file)
--- a/kernel/drivers/spi/spi-xilinx.c
+++ b/kernel/drivers/spi/spi-xilinx.c
@@ -270,6 +270,7 @@ static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
 
        while (remaining_words) {
                int n_words, tx_words, rx_words;
+               u32 sr;
 
                n_words = min(remaining_words, xspi->buffer_size);
 
@@ -284,24 +285,33 @@ static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
                if (use_irq) {
                        xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
                        wait_for_completion(&xspi->done);
-               } else
-                       while (!(xspi->read_fn(xspi->regs + XSPI_SR_OFFSET) &
-                                               XSPI_SR_TX_EMPTY_MASK))
-                               ;
-
-               /* A transmit has just completed. Process received data and
-                * check for more data to transmit. Always inhibit the
-                * transmitter while the Isr refills the transmit register/FIFO,
-                * or make sure it is stopped if we're done.
-                */
-               if (use_irq)
+                       /* A transmit has just completed. Process received data
+                        * and check for more data to transmit. Always inhibit
+                        * the transmitter while the Isr refills the transmit
+                        * register/FIFO, or make sure it is stopped if we're
+                        * done.
+                        */
                        xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
-                              xspi->regs + XSPI_CR_OFFSET);
+                                      xspi->regs + XSPI_CR_OFFSET);
+                       sr = XSPI_SR_TX_EMPTY_MASK;
+               } else
+                       sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
 
                /* Read out all the data from the Rx FIFO */
                rx_words = n_words;
-               while (rx_words--)
-                       xilinx_spi_rx(xspi);
+               while (rx_words) {
+                       if ((sr & XSPI_SR_TX_EMPTY_MASK) && (rx_words > 1)) {
+                               xilinx_spi_rx(xspi);
+                               rx_words--;
+                               continue;
+                       }
+
+                       sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
+                       if (!(sr & XSPI_SR_RX_EMPTY_MASK)) {
+                               xilinx_spi_rx(xspi);
+                               rx_words--;
+                       }
+               }
 
                remaining_words -= n_words;
        }