Some SPI controller do not support full-duplex SPI transfers. This patch changes the SPI transfer into 2 separate transfers - or 1, if no data is to transmitted.
With this change, no buffers need to be allocated anymore. We use the TX and RX buffers that are passed to spi_mem_exec_op() directly.
Signed-off-by: Stefan Roese sr@denx.de Suggested-by: Boris Brezillon boris.brezillon@bootlin.com Cc: Miquel Raynal miquel.raynal@bootlin.com Cc: Boris Brezillon boris.brezillon@bootlin.com Cc: Jagan Teki jagan@openedev.com --- v2: - Replaces patch "spi: spi-mem: Add optional half-duplex SPI transfer mode" from first patchset version - No compile-time option but the default to use 2 separate SPI messages to transfer the command and data
drivers/spi/spi-mem.c | 74 +++++++++++++++++++++++-------------------- 1 file changed, 39 insertions(+), 35 deletions(-)
diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c index 07ce799170..84e33aa979 100644 --- a/drivers/spi/spi-mem.c +++ b/drivers/spi/spi-mem.c @@ -15,6 +15,8 @@ #include <spi-mem.h> #endif
+#define OP_BUFFER_SIZE_MAX 16 /* Max size for cmd + addr + dummy */ + #ifndef __UBOOT__ /** * spi_controller_dma_map_mem_op_data() - DMA-map the buffer attached to a @@ -200,8 +202,12 @@ int spi_mem_exec_op(struct spi_slave *slave, const struct spi_mem_op *op) bool tx_data = op->data.nbytes && (op->data.dir == SPI_MEM_DATA_OUT); struct udevice *bus = slave->dev->parent; struct dm_spi_ops *ops = spi_get_ops(bus); - unsigned int xfer_len, pos = 0; - u8 *tx_buf, *rx_buf = NULL; + unsigned int pos = 0; + const u8 *tx_buf; + u8 *rx_buf; + u8 op_buf[OP_BUFFER_SIZE_MAX]; + int op_len; + u32 flag; int ret; int i;
@@ -330,67 +336,65 @@ int spi_mem_exec_op(struct spi_slave *slave, const struct spi_mem_op *op) return -ENOTSUPP; }
- xfer_len = sizeof(op->cmd.opcode) + op->addr.nbytes + - op->dummy.nbytes + op->data.nbytes; + tx_buf = op->data.buf.out; + rx_buf = op->data.buf.in;
- /* - * Allocate a buffer to transmit the CMD, ADDR cycles with kmalloc() so - * we're guaranteed that this buffer is DMA-able, as required by the - * SPI layer. - */ - tx_buf = kzalloc(xfer_len, GFP_KERNEL); - if (!tx_buf) - return -ENOMEM; - - if (rx_data) { - rx_buf = kzalloc(xfer_len, GFP_KERNEL); - if (!rx_buf) - return -ENOMEM; + op_len = sizeof(op->cmd.opcode) + op->addr.nbytes + op->dummy.nbytes; + if (op_len > OP_BUFFER_SIZE_MAX) { + printf("Length for cmd+addr+dummy too big (%d)\n", op_len); + return -EIO; } + memset(op_buf, 0x00, op_len);
ret = spi_claim_bus(slave); if (ret < 0) return ret;
- tx_buf[pos++] = op->cmd.opcode; + op_buf[pos++] = op->cmd.opcode;
if (op->addr.nbytes) { for (i = 0; i < op->addr.nbytes; i++) - tx_buf[pos + i] = op->addr.val >> - (8 * (op->addr.nbytes - i - 1)); + op_buf[pos + i] = op->addr.val >> + (8 * (op->addr.nbytes - i - 1));
pos += op->addr.nbytes; }
- if (op->dummy.nbytes) { - memset(tx_buf + pos, 0xff, op->dummy.nbytes); - pos += op->dummy.nbytes; + if (op->dummy.nbytes) + memset(op_buf + pos, 0xff, op->dummy.nbytes); + + /* 1st transfer: opcode + address + dummy cycles */ + flag = SPI_XFER_BEGIN; + /* Make sure to set END bit if no tx or rx data messages follow */ + if (!tx_data && !rx_data) + flag |= SPI_XFER_END; + ret = spi_xfer(slave, op_len * 8, op_buf, NULL, flag); + + if (tx_data) { + /* 2nd transfer a: tx data path */ + ret = spi_xfer(slave, op->data.nbytes * 8, tx_buf, NULL, + SPI_XFER_END); }
- if (tx_data) - memcpy(tx_buf + pos, op->data.buf.out, op->data.nbytes); + if (rx_data) { + /* 2nd transfer b: rx data path */ + ret = spi_xfer(slave, op->data.nbytes * 8, NULL, rx_buf, + SPI_XFER_END); + }
- ret = spi_xfer(slave, xfer_len * 8, tx_buf, rx_buf, - SPI_XFER_BEGIN | SPI_XFER_END); spi_release_bus(slave);
for (i = 0; i < pos; i++) - debug("%02x ", tx_buf[i]); + debug("%02x ", op_buf[i]); debug("| [%dB %s] ", tx_data || rx_data ? op->data.nbytes : 0, tx_data || rx_data ? (tx_data ? "out" : "in") : "-"); - for (; i < xfer_len; i++) + for (i = 0; i < op->data.nbytes; i++) debug("%02x ", tx_data ? tx_buf[i] : rx_buf[i]); debug("[ret %d]\n", ret);
if (ret < 0) return ret; - - if (rx_data) - memcpy(op->data.buf.in, rx_buf + pos, op->data.nbytes); - - kfree(tx_buf); - kfree(rx_buf); #endif /* __UBOOT__ */
return 0;