spi: zynqmp-gqspi: Clean up fillgenfifo

This function does a lot more work (assigning things multiple times,
masking unnecessarily, comparing to zero, using superfluous parentheses)
than it needs to. This makes it difficult to understand and modify.
Clean it up. No functional change intended.

Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Link: https://patch.msgid.link/20250116224130.2684544-5-sean.anderson@linux.dev
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
index b35c335dd18346e7e8d32359deff212c7261cb34..fb08dd29e59053d4682277dd526911bf58c55662 100644 (file)
--- a/drivers/spi/spi-zynqmp-gqspi.c
+++ b/drivers/spi/spi-zynqmp-gqspi.c
@@ -82,7 +82,6 @@
 #define GQSPI_GENFIFO_RX                       0x00020000
 #define GQSPI_GENFIFO_STRIPE                   0x00040000
 #define GQSPI_GENFIFO_POLL                     0x00080000
-#define GQSPI_GENFIFO_EXP_START                        0x00000100
 #define GQSPI_FIFO_CTRL_RST_RX_FIFO_MASK       0x00000004
 #define GQSPI_FIFO_CTRL_RST_TX_FIFO_MASK       0x00000002
 #define GQSPI_FIFO_CTRL_RST_GEN_FIFO_MASK      0x00000001
@@ -672,71 +671,50 @@ static void zynqmp_qspi_readrxfifo(struct zynqmp_qspi *xqspi, u32 size)
 static void zynqmp_qspi_fillgenfifo(struct zynqmp_qspi *xqspi, u8 nbits,
                                    u32 genfifoentry)
 {
-       u32 transfer_len = 0;
+       u32 transfer_len, tempcount, exponent;
+       u8 imm_data;
 
-       if (xqspi->txbuf) {
-               genfifoentry &= ~GQSPI_GENFIFO_RX;
-               genfifoentry |= GQSPI_GENFIFO_DATA_XFER;
-               genfifoentry |= GQSPI_GENFIFO_TX;
-               transfer_len = xqspi->bytes_to_transfer;
-       } else if (xqspi->rxbuf) {
-               genfifoentry &= ~GQSPI_GENFIFO_TX;
-               genfifoentry |= GQSPI_GENFIFO_DATA_XFER;
+       genfifoentry |= GQSPI_GENFIFO_DATA_XFER;
+       if (xqspi->rxbuf) {
                genfifoentry |= GQSPI_GENFIFO_RX;
                if (xqspi->mode == GQSPI_MODE_DMA)
                        transfer_len = xqspi->dma_rx_bytes;
                else
                        transfer_len = xqspi->bytes_to_receive;
        } else {
-               /* Sending dummy circles here */
-               genfifoentry &= ~(GQSPI_GENFIFO_TX | GQSPI_GENFIFO_RX);
-               genfifoentry |= GQSPI_GENFIFO_DATA_XFER;
                transfer_len = xqspi->bytes_to_transfer;
        }
+
+       if (xqspi->txbuf)
+               genfifoentry |= GQSPI_GENFIFO_TX;
+
        genfifoentry |= zynqmp_qspi_selectspimode(xqspi, nbits);
        xqspi->genfifoentry = genfifoentry;
        dev_dbg(xqspi->dev, "genfifo %05x transfer_len %u\n",
                genfifoentry, transfer_len);
 
-       if ((transfer_len) < GQSPI_GENFIFO_IMM_DATA_MASK) {
-               genfifoentry &= ~GQSPI_GENFIFO_IMM_DATA_MASK;
-               genfifoentry |= transfer_len;
-               zynqmp_gqspi_write(xqspi, GQSPI_GEN_FIFO_OFST, genfifoentry);
-       } else {
-               int tempcount = transfer_len;
-               u32 exponent = 8;       /* 2^8 = 256 */
-               u8 imm_data = tempcount & 0xFF;
-
-               tempcount &= ~(tempcount & 0xFF);
-               /* Immediate entry */
-               if (tempcount != 0) {
-                       /* Exponent entries */
-                       genfifoentry |= GQSPI_GENFIFO_EXP;
-                       while (tempcount != 0) {
-                               if (tempcount & GQSPI_GENFIFO_EXP_START) {
-                                       genfifoentry &=
-                                               ~GQSPI_GENFIFO_IMM_DATA_MASK;
-                                       genfifoentry |= exponent;
-                                       zynqmp_gqspi_write(xqspi,
-                                                          GQSPI_GEN_FIFO_OFST,
-                                                          genfifoentry);
-                               }
-                               tempcount = tempcount >> 1;
-                               exponent++;
-                       }
-               }
-               if (imm_data != 0) {
-                       genfifoentry &= ~GQSPI_GENFIFO_EXP;
-                       genfifoentry &= ~GQSPI_GENFIFO_IMM_DATA_MASK;
-                       genfifoentry |= (u8)(imm_data & 0xFF);
+       /* Exponent entries */
+       imm_data = transfer_len;
+       tempcount = transfer_len >> 8;
+       exponent = 8;
+       genfifoentry |= GQSPI_GENFIFO_EXP;
+       while (tempcount) {
+               if (tempcount & 1)
                        zynqmp_gqspi_write(xqspi, GQSPI_GEN_FIFO_OFST,
-                                          genfifoentry);
-               }
-       }
-       if (xqspi->mode == GQSPI_MODE_IO && xqspi->rxbuf) {
-               /* Dummy generic FIFO entry */
-               zynqmp_gqspi_write(xqspi, GQSPI_GEN_FIFO_OFST, 0x0);
+                                          genfifoentry | exponent);
+               tempcount >>= 1;
+               exponent++;
        }
+
+       /* Immediate entry */
+       genfifoentry &= ~GQSPI_GENFIFO_EXP;
+       if (imm_data)
+               zynqmp_gqspi_write(xqspi, GQSPI_GEN_FIFO_OFST,
+                                  genfifoentry | imm_data);
+
+       /* Dummy generic FIFO entry */
+       if (xqspi->mode == GQSPI_MODE_IO && xqspi->rxbuf)
+               zynqmp_gqspi_write(xqspi, GQSPI_GEN_FIFO_OFST, 0);
 }
 
 /**