diff mbox series

[net-next,03/47] can: mcp251xfd: regmap: optimizing transfer size for CRC transfers size 1

Message ID 20230206131620.2758724-4-mkl@pengutronix.de (mailing list archive)
State Accepted
Commit 2e8ca20b40e5ba556cd38495df418b2d0c568195
Delegated to: Netdev Maintainers
Headers show
Series [net-next,01/47] can: gw: give feedback on missing CGW_FLAGS_CAN_IIF_TX_OK flag | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Pull request is its own cover letter
netdev/patch_count warning Series longer than 15 patches
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 4 maintainers not CCed: mani@kernel.org wg@grandegger.com edumazet@google.com pabeni@redhat.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning CHECK: Alignment should match open parenthesis WARNING: line length of 83 exceeds 80 columns WARNING: line length of 85 exceeds 80 columns WARNING: line length of 87 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Marc Kleine-Budde Feb. 6, 2023, 1:15 p.m. UTC 
From: Thomas Kopp <thomas.kopp@microchip.com>

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: Thomas Kopp <thomas.kopp@microchip.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 .../net/can/spi/mcp251xfd/mcp251xfd-ring.c    | 18 ++++++++++---
 drivers/net/can/spi/mcp251xfd/mcp251xfd.h     | 26 ++++++++++++++++---
 2 files changed, 36 insertions(+), 8 deletions(-)
diff mbox series

Patch

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);