Commit 2e8ca20b authored by Thomas Kopp's avatar Thomas Kopp Committed by Marc Kleine-Budde
Browse files

can: mcp251xfd: regmap: optimizing transfer size for CRC transfers size 1 

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@microchip.com
- change logic to remove 1 level of indention

Link: https://lore.kernel.org/all/20230202141811.2581795-1-mkl@pengutronix.de


Signed-off-by: default avatarThomas Kopp <thomas.kopp@microchip.com>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent c6adf659

drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c

+14 −4
Original line number Diff line number Diff line
@@ -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;

drivers/net/can/spi/mcp251xfd/mcp251xfd.h

+22 −4
Original line number Diff line number Diff line
@@ -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) {

		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);