openwrt/target/linux/bcm27xx/patches-6.6/950-1189-spi-dw-Save-bandwidth-with-the-TMOD_TO-feature.patch
Álvaro Fernández Rojas 0171157d45 bcm27xx: update to latest RPi patches
The patches were generated from the RPi repo with the following command:
git format-patch v6.6.44..rpi-6.6.y

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
2024-08-06 18:38:00 +02:00

67 lines
2.0 KiB
Diff

From 6014649de765a8a1f95c146ca72214ff0ba4ba89 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Mon, 1 Jul 2024 15:49:14 +0100
Subject: [PATCH 1189/1215] spi: dw: Save bandwidth with the TMOD_TO feature
TMOD_TO is the transmit-only mode that doesn't put data into the receive
FIFO. Using TMOD_TO when the user doesn't want the received data saves
CPU time and memory bandwidth.
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
drivers/spi/spi-dw-core.c | 27 +++++++++++++++++----------
1 file changed, 17 insertions(+), 10 deletions(-)
--- a/drivers/spi/spi-dw-core.c
+++ b/drivers/spi/spi-dw-core.c
@@ -225,12 +225,17 @@ static irqreturn_t dw_spi_transfer_handl
* final stage of the transfer. By doing so we'll get the next IRQ
* right when the leftover incoming data is received.
*/
- dw_reader(dws);
- if (!dws->rx_len) {
- dw_spi_mask_intr(dws, 0xff);
+ if (dws->rx_len) {
+ dw_reader(dws);
+ if (!dws->rx_len) {
+ dw_spi_mask_intr(dws, 0xff);
+ spi_finalize_current_transfer(dws->host);
+ } else if (dws->rx_len <= dw_readl(dws, DW_SPI_RXFTLR)) {
+ dw_writel(dws, DW_SPI_RXFTLR, dws->rx_len - 1);
+ }
+ } else if (!dws->tx_len) {
+ dw_spi_mask_intr(dws, DW_SPI_INT_TXEI);
spi_finalize_current_transfer(dws->host);
- } else if (dws->rx_len <= dw_readl(dws, DW_SPI_RXFTLR)) {
- dw_writel(dws, DW_SPI_RXFTLR, dws->rx_len - 1);
}
/*
@@ -239,12 +244,9 @@ static irqreturn_t dw_spi_transfer_handl
* have the TXE IRQ flood at the final stage of the transfer.
*/
if (irq_status & DW_SPI_INT_TXEI) {
- dw_writer(dws);
- if (!dws->tx_len) {
+ if (!dws->tx_len)
dw_spi_mask_intr(dws, DW_SPI_INT_TXEI);
- if (!dws->rx_len)
- spi_finalize_current_transfer(dws->host);
- }
+ dw_writer(dws);
}
return IRQ_HANDLED;
@@ -437,6 +439,11 @@ static int dw_spi_transfer_one(struct sp
dws->rx = transfer->rx_buf;
dws->rx_len = dws->tx_len;
+ if (!dws->rx) {
+ dws->rx_len = 0;
+ cfg.tmode = DW_SPI_CTRLR0_TMOD_TO;
+ }
+
/* Ensure the data above is visible for all CPUs */
smp_mb();