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Date: Thu, 7 Jan 2021 10:48:56 +0100
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, kuba@...nel.org, linux-can@...r.kernel.org,
kernel@...gutronix.de, Marc Kleine-Budde <mkl@...gutronix.de>,
Dan Murphy <dmurphy@...com>, Sean Nyekjaer <sean@...nix.com>
Subject: [net-next 15/19] can: tcan4x5x: rework SPI access
This patch reworks the SPI access and fixes several probems:
- tcan4x5x_regmap_gather_write(), tcan4x5x_regmap_read():
Do not place variable "addr" on stack and use it as buffer for SPI
transfer. Buffers for SPI transfers must be allocated from DMA save
memory.
- tcan4x5x_regmap_gather_write(), tcan4x5x_regmap_read():
Halfe number of SPI transfers by using a single buffer + memcpy().
This improves the performance, especially on SPI controllers, which
use interrupt based transfers.
- Use "8" bits per word, not "32". This makes it possible to use this
driver on SoCs like the Raspberry Pi, which SPI host controller
drivers only support 8 bits per word.
Note: this breaks half duplex only controllers. Support for them will be
re-added in the next patch.
Reviewed-by: Dan Murphy <dmurphy@...com>
Tested-by: Sean Nyekjaer <sean@...nix.com>
Link: https://lore.kernel.org/r/20201215231746.1132907-16-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
drivers/net/can/m_can/tcan4x5x-core.c | 2 +-
drivers/net/can/m_can/tcan4x5x-regmap.c | 87 +++++++++++++++++--------
drivers/net/can/m_can/tcan4x5x.h | 23 +++++++
3 files changed, 84 insertions(+), 28 deletions(-)
diff --git a/drivers/net/can/m_can/tcan4x5x-core.c b/drivers/net/can/m_can/tcan4x5x-core.c
index 739b8f89a335..d37843a74663 100644
--- a/drivers/net/can/m_can/tcan4x5x-core.c
+++ b/drivers/net/can/m_can/tcan4x5x-core.c
@@ -380,7 +380,7 @@ static int tcan4x5x_can_probe(struct spi_device *spi)
spi_set_drvdata(spi, priv);
/* Configure the SPI bus */
- spi->bits_per_word = 32;
+ spi->bits_per_word = 8;
ret = spi_setup(spi);
if (ret)
goto out_m_can_class_free_dev;
diff --git a/drivers/net/can/m_can/tcan4x5x-regmap.c b/drivers/net/can/m_can/tcan4x5x-regmap.c
index 5ea162578619..660e9d87dffb 100644
--- a/drivers/net/can/m_can/tcan4x5x-regmap.c
+++ b/drivers/net/can/m_can/tcan4x5x-regmap.c
@@ -9,48 +9,76 @@
#include "tcan4x5x.h"
-#define TCAN4X5X_WRITE_CMD (0x61 << 24)
-#define TCAN4X5X_READ_CMD (0x41 << 24)
+#define TCAN4X5X_SPI_INSTRUCTION_WRITE (0x61 << 24)
+#define TCAN4X5X_SPI_INSTRUCTION_READ (0x41 << 24)
#define TCAN4X5X_MAX_REGISTER 0x8ffc
-static int tcan4x5x_regmap_gather_write(void *context, const void *reg,
- size_t reg_len, const void *val,
- size_t val_len)
+static int tcan4x5x_regmap_gather_write(void *context,
+ const void *reg, size_t reg_len,
+ const void *val, size_t val_len)
{
struct spi_device *spi = context;
- struct spi_message m;
- u32 addr;
- struct spi_transfer t[2] = {
- { .tx_buf = &addr, .len = reg_len, .cs_change = 0,},
- { .tx_buf = val, .len = val_len, },
+ struct tcan4x5x_priv *priv = spi_get_drvdata(spi);
+ struct tcan4x5x_map_buf *buf_tx = &priv->map_buf_tx;
+ struct spi_transfer xfer[] = {
+ {
+ .tx_buf = buf_tx,
+ .len = sizeof(buf_tx->cmd) + val_len,
+ },
};
- addr = TCAN4X5X_WRITE_CMD | (*((u16 *)reg) << 8) | val_len >> 2;
+ memcpy(&buf_tx->cmd, reg, sizeof(buf_tx->cmd.cmd) +
+ sizeof(buf_tx->cmd.addr));
+ tcan4x5x_spi_cmd_set_len(&buf_tx->cmd, val_len);
+ memcpy(buf_tx->data, val, val_len);
- spi_message_init(&m);
- spi_message_add_tail(&t[0], &m);
- spi_message_add_tail(&t[1], &m);
-
- return spi_sync(spi, &m);
+ return spi_sync_transfer(spi, xfer, ARRAY_SIZE(xfer));
}
static int tcan4x5x_regmap_write(void *context, const void *data, size_t count)
{
- return tcan4x5x_regmap_gather_write(context, data, sizeof(u32),
- data + sizeof(u32),
- count - sizeof(u32));
+ return tcan4x5x_regmap_gather_write(context, data, sizeof(__be32),
+ data + sizeof(__be32),
+ count - sizeof(__be32));
}
static int tcan4x5x_regmap_read(void *context,
- const void *reg, size_t reg_size,
- void *val, size_t val_size)
+ const void *reg_buf, size_t reg_len,
+ void *val_buf, size_t val_len)
{
struct spi_device *spi = context;
+ struct tcan4x5x_priv *priv = spi_get_drvdata(spi);
+ struct tcan4x5x_map_buf *buf_rx = &priv->map_buf_rx;
+ struct tcan4x5x_map_buf *buf_tx = &priv->map_buf_tx;
+ struct spi_transfer xfer[] = {
+ {
+ .tx_buf = buf_tx,
+ }
+ };
+ struct spi_message msg;
+ int err;
+
+ spi_message_init(&msg);
+ spi_message_add_tail(&xfer[0], &msg);
+
+ memcpy(&buf_tx->cmd, reg_buf, sizeof(buf_tx->cmd.cmd) +
+ sizeof(buf_tx->cmd.addr));
+ tcan4x5x_spi_cmd_set_len(&buf_tx->cmd, val_len);
+
+ xfer[0].rx_buf = buf_rx;
+ xfer[0].len = sizeof(buf_tx->cmd) + val_len;
- u32 addr = TCAN4X5X_READ_CMD | (*((u16 *)reg) << 8) | val_size >> 2;
+ if (TCAN4X5X_SANITIZE_SPI)
+ memset(buf_tx->data, 0x0, val_len);
- return spi_write_then_read(spi, &addr, reg_size, (u32 *)val, val_size);
+ err = spi_sync(spi, &msg);
+ if (err)
+ return err;
+
+ memcpy(val_buf, buf_rx->data, val_len);
+
+ return 0;
}
static const struct regmap_range tcan4x5x_reg_table_yes_range[] = {
@@ -66,21 +94,26 @@ static const struct regmap_access_table tcan4x5x_reg_table = {
};
static const struct regmap_config tcan4x5x_regmap = {
- .reg_bits = 32,
+ .reg_bits = 24,
.reg_stride = 4,
+ .pad_bits = 8,
.val_bits = 32,
.wr_table = &tcan4x5x_reg_table,
.rd_table = &tcan4x5x_reg_table,
- .cache_type = REGCACHE_NONE,
.max_register = TCAN4X5X_MAX_REGISTER,
+ .cache_type = REGCACHE_NONE,
+ .read_flag_mask = (__force unsigned long)
+ cpu_to_be32(TCAN4X5X_SPI_INSTRUCTION_READ),
+ .write_flag_mask = (__force unsigned long)
+ cpu_to_be32(TCAN4X5X_SPI_INSTRUCTION_WRITE),
};
static const struct regmap_bus tcan4x5x_bus = {
.write = tcan4x5x_regmap_write,
.gather_write = tcan4x5x_regmap_gather_write,
.read = tcan4x5x_regmap_read,
- .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
- .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
+ .reg_format_endian_default = REGMAP_ENDIAN_BIG,
+ .val_format_endian_default = REGMAP_ENDIAN_BIG,
.max_raw_read = 256,
.max_raw_write = 256,
};
diff --git a/drivers/net/can/m_can/tcan4x5x.h b/drivers/net/can/m_can/tcan4x5x.h
index e5bdd91b8005..7bf264f8e81f 100644
--- a/drivers/net/can/m_can/tcan4x5x.h
+++ b/drivers/net/can/m_can/tcan4x5x.h
@@ -17,6 +17,19 @@
#include "m_can.h"
+#define TCAN4X5X_SANITIZE_SPI 1
+
+struct __packed tcan4x5x_buf_cmd {
+ u8 cmd;
+ __be16 addr;
+ u8 len;
+};
+
+struct __packed tcan4x5x_map_buf {
+ struct tcan4x5x_buf_cmd cmd;
+ u8 data[256 * sizeof(u32)];
+} ____cacheline_aligned;
+
struct tcan4x5x_priv {
struct m_can_classdev cdev;
@@ -27,8 +40,18 @@ struct tcan4x5x_priv {
struct gpio_desc *device_wake_gpio;
struct gpio_desc *device_state_gpio;
struct regulator *power;
+
+ struct tcan4x5x_map_buf map_buf_rx;
+ struct tcan4x5x_map_buf map_buf_tx;
};
+static inline void
+tcan4x5x_spi_cmd_set_len(struct tcan4x5x_buf_cmd *cmd, u8 len)
+{
+ /* number of u32 */
+ cmd->len = len >> 2;
+}
+
int tcan4x5x_regmap_init(struct tcan4x5x_priv *priv);
#endif
--
2.29.2
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