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List: linux-can
Subject: [net-next 06/14] can: mcp251xfd: tef-path: reduce number of SPI core requests to set UINC bit
From: Marc Kleine-Budde <mkl () pengutronix ! de>
Date: 2020-11-30 14:14:24
Message-ID: 20201130141432.278219-7-mkl () pengutronix ! de
[Download RAW message or body]
Reduce the number of separate SPI core requests when setting the UINC bit in
the TEF FIFO, and instead batch them up into a single SPI core request.
Link: https://lore.kernel.org/r/20201126132144.351154-6-mkl@pengutronix.de
Tested-by: Thomas Kopp <thomas.kopp@microchip.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
.../net/can/spi/mcp251xfd/mcp251xfd-core.c | 64 +++++++++++++++----
drivers/net/can/spi/mcp251xfd/mcp251xfd.h | 3 +
2 files changed, 55 insertions(+), 12 deletions(-)
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c \
b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c index 551499d9737f..20cbd5c446f5 \
100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -340,6 +340,23 @@ static void mcp251xfd_ring_init(struct mcp251xfd_priv *priv)
tef_ring->head = 0;
tef_ring->tail = 0;
+ /* FIFO increment TEF tail pointer */
+ addr = MCP251XFD_REG_TEFCON;
+ val = MCP251XFD_REG_TEFCON_UINC;
+ len = mcp251xfd_cmd_prepare_write_reg(priv, &tef_ring->uinc_buf,
+ addr, val, val);
+
+ for (j = 0; j < ARRAY_SIZE(tef_ring->uinc_xfer); j++) {
+ struct spi_transfer *xfer;
+
+ xfer = &tef_ring->uinc_xfer[j];
+ xfer->tx_buf = &tef_ring->uinc_buf;
+ xfer->len = len;
+ xfer->cs_change = 1;
+ xfer->cs_change_delay.value = 0;
+ xfer->cs_change_delay.unit = SPI_DELAY_UNIT_NSECS;
+ }
+
/* TX */
tx_ring = priv->tx;
tx_ring->head = 0;
@@ -1231,10 +1248,8 @@ static int
mcp251xfd_handle_tefif_one(struct mcp251xfd_priv *priv,
const struct mcp251xfd_hw_tef_obj *hw_tef_obj)
{
- struct mcp251xfd_tx_ring *tx_ring = priv->tx;
struct net_device_stats *stats = &priv->ndev->stats;
u32 seq, seq_masked, tef_tail_masked;
- int err;
seq = FIELD_GET(MCP251XFD_OBJ_FLAGS_SEQ_MCP2518FD_MASK,
hw_tef_obj->flags);
@@ -1255,18 +1270,9 @@ mcp251xfd_handle_tefif_one(struct mcp251xfd_priv *priv,
mcp251xfd_get_tef_tail(priv),
hw_tef_obj->ts);
stats->tx_packets++;
-
- /* finally increment the TEF pointer */
- err = regmap_update_bits(priv->map_reg, MCP251XFD_REG_TEFCON,
- GENMASK(15, 8),
- MCP251XFD_REG_TEFCON_UINC);
- if (err)
- return err;
-
priv->tef->tail++;
- tx_ring->tail++;
- return mcp251xfd_check_tef_tail(priv);
+ return 0;
}
static int mcp251xfd_tef_ring_update(struct mcp251xfd_priv *priv)
@@ -1353,6 +1359,40 @@ static int mcp251xfd_handle_tefif(struct mcp251xfd_priv *priv)
}
out_netif_wake_queue:
+ len = i; /* number of handled goods TEFs */
+ if (len) {
+ struct mcp251xfd_tef_ring *ring = priv->tef;
+ struct mcp251xfd_tx_ring *tx_ring = priv->tx;
+ struct spi_transfer *last_xfer;
+
+ tx_ring->tail += len;
+
+ /* Increment the TEF FIFO tail pointer 'len' times in
+ * a single SPI message.
+ */
+
+ /* Note:
+ *
+ * "cs_change == 1" on the last transfer results in an
+ * active chip select after the complete SPI
+ * message. This causes the controller to interpret
+ * the next register access as data. Temporary set
+ * "cs_change" of the last transfer to "0" to properly
+ * deactivate the chip select at the end of the
+ * message.
+ */
+ last_xfer = &ring->uinc_xfer[len - 1];
+ last_xfer->cs_change = 0;
+ err = spi_sync_transfer(priv->spi, ring->uinc_xfer, len);
+ last_xfer->cs_change = 1;
+ if (err)
+ return err;
+
+ err = mcp251xfd_check_tef_tail(priv);
+ if (err)
+ return err;
+ }
+
mcp251xfd_ecc_tefif_successful(priv);
if (mcp251xfd_get_tx_free(priv->tx)) {
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h \
b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h index 299dbf72e24b..cb6398c2a560 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
@@ -504,6 +504,9 @@ struct mcp251xfd_tef_ring {
/* u8 obj_num equals tx_ring->obj_num */
/* u8 obj_size equals sizeof(struct mcp251xfd_hw_tef_obj) */
+
+ union mcp251xfd_write_reg_buf uinc_buf;
+ struct spi_transfer uinc_xfer[MCP251XFD_TX_OBJ_NUM_MAX];
};
struct mcp251xfd_tx_ring {
--
2.29.2
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