From: Thomas Kopp <thomas.kopp@xxxxxxxxxxxxx> For CRC transfers with size 1 it is more efficient to use the write_safe command instead of the write_crc command. This saves the length byte on the SPI transfer. changes since v1: https://lore.kernel.org/all/20230127124258.2764-1-thomas.kopp@xxxxxxxxxxxxx - change logic to remove 1 level of indention Link: https://lore.kernel.org/all/20230202141811.2581795-1-mkl@xxxxxxxxxxxxxx Signed-off-by: Thomas Kopp <thomas.kopp@xxxxxxxxxxxxx> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> --- .../net/can/spi/mcp251xfd/mcp251xfd-ring.c | 18 ++++++++++--- drivers/net/can/spi/mcp251xfd/mcp251xfd.h | 26 ++++++++++++++++--- 2 files changed, 36 insertions(+), 8 deletions(-) diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c index bf3f0f150199..bfe4caa0c99d 100644 --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c @@ -30,11 +30,23 @@ mcp251xfd_cmd_prepare_write_reg(const struct mcp251xfd_priv *priv, last_byte = mcp251xfd_last_byte_set(mask); len = last_byte - first_byte + 1; - data = mcp251xfd_spi_cmd_write(priv, write_reg_buf, reg + first_byte); + data = mcp251xfd_spi_cmd_write(priv, write_reg_buf, reg + first_byte, len); val_le32 = cpu_to_le32(val >> BITS_PER_BYTE * first_byte); memcpy(data, &val_le32, len); - if (priv->devtype_data.quirks & MCP251XFD_QUIRK_CRC_REG) { + if (!(priv->devtype_data.quirks & MCP251XFD_QUIRK_CRC_REG)) { + len += sizeof(write_reg_buf->nocrc.cmd); + } else if (len == 1) { + u16 crc; + + /* CRC */ + len += sizeof(write_reg_buf->safe.cmd); + crc = mcp251xfd_crc16_compute(&write_reg_buf->safe, len); + put_unaligned_be16(crc, (void *)write_reg_buf + len); + + /* Total length */ + len += sizeof(write_reg_buf->safe.crc); + } else { u16 crc; mcp251xfd_spi_cmd_crc_set_len_in_reg(&write_reg_buf->crc.cmd, @@ -46,8 +58,6 @@ mcp251xfd_cmd_prepare_write_reg(const struct mcp251xfd_priv *priv, /* Total length */ len += sizeof(write_reg_buf->crc.crc); - } else { - len += sizeof(write_reg_buf->nocrc.cmd); } return len; diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h index 2b0309fedfac..7024ff0cc2c0 100644 --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h @@ -504,6 +504,11 @@ union mcp251xfd_write_reg_buf { u8 data[4]; __be16 crc; } crc; + struct __packed { + struct mcp251xfd_buf_cmd cmd; + u8 data[1]; + __be16 crc; + } safe; } ____cacheline_aligned; struct mcp251xfd_tx_obj { @@ -758,6 +763,13 @@ mcp251xfd_spi_cmd_write_crc_set_addr(struct mcp251xfd_buf_cmd_crc *cmd, cmd->cmd = cpu_to_be16(MCP251XFD_SPI_INSTRUCTION_WRITE_CRC | addr); } +static inline void +mcp251xfd_spi_cmd_write_safe_set_addr(struct mcp251xfd_buf_cmd *cmd, + u16 addr) +{ + cmd->cmd = cpu_to_be16(MCP251XFD_SPI_INSTRUCTION_WRITE_CRC_SAFE | addr); +} + static inline void mcp251xfd_spi_cmd_write_crc(struct mcp251xfd_buf_cmd_crc *cmd, u16 addr, u16 len) @@ -769,14 +781,20 @@ mcp251xfd_spi_cmd_write_crc(struct mcp251xfd_buf_cmd_crc *cmd, static inline u8 * mcp251xfd_spi_cmd_write(const struct mcp251xfd_priv *priv, union mcp251xfd_write_reg_buf *write_reg_buf, - u16 addr) + u16 addr, u8 len) { u8 *data; if (priv->devtype_data.quirks & MCP251XFD_QUIRK_CRC_REG) { - mcp251xfd_spi_cmd_write_crc_set_addr(&write_reg_buf->crc.cmd, - addr); - data = write_reg_buf->crc.data; + if (len == 1) { + mcp251xfd_spi_cmd_write_safe_set_addr(&write_reg_buf->safe.cmd, + addr); + data = write_reg_buf->safe.data; + } else { + mcp251xfd_spi_cmd_write_crc_set_addr(&write_reg_buf->crc.cmd, + addr); + data = write_reg_buf->crc.data; + } } else { mcp251xfd_spi_cmd_write_nocrc(&write_reg_buf->nocrc.cmd, addr); -- 2.39.1
