* [net-next 0/2] can: mcp251xfd: rx-path: reduce number of SPI core requests to set UINC bit
@ 2020-11-23 11:16 Marc Kleine-Budde
2020-11-23 11:16 ` [net-next 1/2] can: mcp251xfd: mcp25xxfd_ring_alloc(): add define instead open coding the maximum number of RX objects Marc Kleine-Budde
2020-11-23 11:16 ` [net-next 2/2] can: mcp251xfd: rx-path: reduce number of SPI core requests to set UINC bit Marc Kleine-Budde
0 siblings, 2 replies; 3+ messages in thread
From: Marc Kleine-Budde @ 2020-11-23 11:16 UTC (permalink / raw)
To: linux-can; +Cc: Manivannan Sadhasivam, Thomas Kopp
Hello,
this is a short series to reduce the number SPI core requests to increment the
UINC bit after RX handling. This is done by chaining the individual UINC bit
changes into a single SPI message consisting of several transfers.
regards,
Marc
^ permalink raw reply [flat|nested] 3+ messages in thread
* [net-next 1/2] can: mcp251xfd: mcp25xxfd_ring_alloc(): add define instead open coding the maximum number of RX objects
2020-11-23 11:16 [net-next 0/2] can: mcp251xfd: rx-path: reduce number of SPI core requests to set UINC bit Marc Kleine-Budde
@ 2020-11-23 11:16 ` Marc Kleine-Budde
2020-11-23 11:16 ` [net-next 2/2] can: mcp251xfd: rx-path: reduce number of SPI core requests to set UINC bit Marc Kleine-Budde
1 sibling, 0 replies; 3+ messages in thread
From: Marc Kleine-Budde @ 2020-11-23 11:16 UTC (permalink / raw)
To: linux-can; +Cc: Manivannan Sadhasivam, Thomas Kopp, Marc Kleine-Budde
This patch add a define for the maximum number of RX objects instead of open
coding it.
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c | 3 ++-
drivers/net/can/spi/mcp251xfd/mcp251xfd.h | 1 +
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index 3297eb7ecc9c..aab972ad10dd 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -416,7 +416,8 @@ static int mcp251xfd_ring_alloc(struct mcp251xfd_priv *priv)
int rx_obj_num;
rx_obj_num = ram_free / rx_obj_size;
- rx_obj_num = min(1 << (fls(rx_obj_num) - 1), 32);
+ rx_obj_num = min(1 << (fls(rx_obj_num) - 1),
+ MCP251XFD_RX_OBJ_NUM_MAX);
rx_ring = kzalloc(sizeof(*rx_ring) + rx_obj_size * rx_obj_num,
GFP_KERNEL);
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
index fa1246e39980..c20c97d01072 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
@@ -368,6 +368,7 @@
* FIFO setup: tef: 8*12 bytes = 96 bytes, tx: 8*16 bytes = 128 bytes
* FIFO setup: tef: 4*12 bytes = 48 bytes, tx: 4*72 bytes = 288 bytes
*/
+#define MCP251XFD_RX_OBJ_NUM_MAX 32
#define MCP251XFD_TX_OBJ_NUM_CAN 8
#define MCP251XFD_TX_OBJ_NUM_CANFD 4
--
2.29.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [net-next 2/2] can: mcp251xfd: rx-path: reduce number of SPI core requests to set UINC bit
2020-11-23 11:16 [net-next 0/2] can: mcp251xfd: rx-path: reduce number of SPI core requests to set UINC bit Marc Kleine-Budde
2020-11-23 11:16 ` [net-next 1/2] can: mcp251xfd: mcp25xxfd_ring_alloc(): add define instead open coding the maximum number of RX objects Marc Kleine-Budde
@ 2020-11-23 11:16 ` Marc Kleine-Budde
1 sibling, 0 replies; 3+ messages in thread
From: Marc Kleine-Budde @ 2020-11-23 11:16 UTC (permalink / raw)
To: linux-can
Cc: Manivannan Sadhasivam, Thomas Kopp, Ursula Maplehurst, Marc Kleine-Budde
From: Ursula Maplehurst <ursula@kangatronix.co.uk>
Reduce the number of separate SPI core requests when setting the UINC bit in
the RX FIFO, and instead batch them up into a single SPI core request.
Link: https://github.com/marckleinebudde/linux/issues/4
Signed-off-by: Ursula Maplehurst <ursula@kangatronix.co.uk>
Co-developed-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
.../net/can/spi/mcp251xfd/mcp251xfd-core.c | 49 ++++++++++++++++---
drivers/net/can/spi/mcp251xfd/mcp251xfd.h | 2 +
2 files changed, 43 insertions(+), 8 deletions(-)
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index aab972ad10dd..4d3f87083efc 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -332,7 +332,7 @@ static void mcp251xfd_ring_init(struct mcp251xfd_priv *priv)
u32 val;
u16 addr;
u8 len;
- int i;
+ int i, j;
/* TEF */
priv->tef.head = 0;
@@ -370,6 +370,23 @@ static void mcp251xfd_ring_init(struct mcp251xfd_priv *priv)
prev_rx_ring->obj_num;
prev_rx_ring = rx_ring;
+
+ /* FIFO increment RX tail pointer */
+ addr = MCP251XFD_REG_FIFOCON(rx_ring->fifo_nr);
+ val = MCP251XFD_REG_FIFOCON_UINC;
+ len = mcp251xfd_cmd_prepare_write_reg(priv, &rx_ring->uinc_buf,
+ addr, val, val);
+
+ for (j = 0; j < ARRAY_SIZE(rx_ring->uinc_xfer); j++) {
+ struct spi_transfer *xfer;
+
+ xfer = &rx_ring->uinc_xfer[j];
+ xfer->tx_buf = &rx_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;
+ }
}
}
@@ -1440,13 +1457,7 @@ mcp251xfd_handle_rxif_one(struct mcp251xfd_priv *priv,
if (err)
stats->rx_fifo_errors++;
- ring->tail++;
-
- /* finally increment the RX pointer */
- return regmap_update_bits(priv->map_reg,
- MCP251XFD_REG_FIFOCON(ring->fifo_nr),
- GENMASK(15, 8),
- MCP251XFD_REG_FIFOCON_UINC);
+ return 0;
}
static inline int
@@ -1470,6 +1481,7 @@ mcp251xfd_handle_rxif_ring(struct mcp251xfd_priv *priv,
struct mcp251xfd_rx_ring *ring)
{
struct mcp251xfd_hw_rx_obj_canfd *hw_rx_obj = ring->obj;
+ struct spi_transfer *last_xfer;
u8 rx_tail, len;
int err, i;
@@ -1492,6 +1504,27 @@ mcp251xfd_handle_rxif_ring(struct mcp251xfd_priv *priv,
if (err)
return err;
}
+
+ /* Increment the RX FIFO tail pointer 'len' times in a
+ * single SPI transfer.
+ */
+ ring->tail += len;
+
+ /* Note:
+ *
+ * "cs_change == 1" on the last transfer results in an
+ * active chip select after the transfer. 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 transfer.
+ */
+ 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;
}
return 0;
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
index c20c97d01072..97dc182e2b42 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
@@ -528,6 +528,8 @@ struct mcp251xfd_rx_ring {
u8 obj_num;
u8 obj_size;
+ union mcp251xfd_write_reg_buf uinc_buf;
+ struct spi_transfer uinc_xfer[MCP251XFD_RX_OBJ_NUM_MAX];
struct mcp251xfd_hw_rx_obj_canfd obj[];
};
--
2.29.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
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