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0171157d45
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>
144 lines
4.2 KiB
Diff
144 lines
4.2 KiB
Diff
From 199e611183de09ad91fe01fc79da78cc9d11ccb6 Mon Sep 17 00:00:00 2001
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From: Phil Elwell <phil@raspberrypi.com>
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Date: Mon, 29 Jul 2024 11:12:38 +0100
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Subject: [PATCH 1201/1215] spi: dw: Fix non-DMA transmit-only transfers
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Ensure the transmit FIFO has emptied before ending the transfer by
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dropping the TX threshold to 0 when the last byte has been pushed into
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the FIFO. Include a similar fix for the non-IRQ paths.
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See: https://github.com/raspberrypi/linux/issues/6285
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Fixes: 6014649de765 ("spi: dw: Save bandwidth with the TMOD_TO feature")
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Signed-off-by: Phil Elwell <phil@raspberrypi.com>
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---
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drivers/spi/spi-dw-core.c | 62 +++++++++++++++++++++++++++++++++------
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drivers/spi/spi-dw.h | 3 ++
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2 files changed, 56 insertions(+), 9 deletions(-)
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--- a/drivers/spi/spi-dw-core.c
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+++ b/drivers/spi/spi-dw-core.c
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@@ -220,6 +220,32 @@ int dw_spi_check_status(struct dw_spi *d
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}
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EXPORT_SYMBOL_NS_GPL(dw_spi_check_status, SPI_DW_CORE);
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+static inline bool dw_spi_ctlr_busy(struct dw_spi *dws)
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+{
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+ return dw_readl(dws, DW_SPI_SR) & DW_SPI_SR_BUSY;
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+}
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+
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+static enum hrtimer_restart dw_spi_hrtimer_handler(struct hrtimer *hr)
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+{
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+ struct dw_spi *dws = container_of(hr, struct dw_spi, hrtimer);
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+
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+ if (!dw_spi_ctlr_busy(dws)) {
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+ spi_finalize_current_transfer(dws->host);
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+ return HRTIMER_NORESTART;
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+ }
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+
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+ if (!dws->idle_wait_retries) {
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+ dev_err(&dws->host->dev, "controller stuck at busy\n");
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+ spi_finalize_current_transfer(dws->host);
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+ return HRTIMER_NORESTART;
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+ }
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+
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+ dws->idle_wait_retries--;
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+ hrtimer_forward_now(hr, dws->idle_wait_interval);
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+
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+ return HRTIMER_RESTART;
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+}
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+
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static irqreturn_t dw_spi_transfer_handler(struct dw_spi *dws)
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{
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u16 irq_status = dw_readl(dws, DW_SPI_ISR);
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@@ -246,7 +272,22 @@ static irqreturn_t dw_spi_transfer_handl
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}
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} else if (!dws->tx_len) {
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dw_spi_mask_intr(dws, DW_SPI_INT_TXEI);
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- spi_finalize_current_transfer(dws->host);
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+ if (dw_spi_ctlr_busy(dws)) {
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+ ktime_t period = ns_to_ktime(DIV_ROUND_UP(NSEC_PER_SEC, dws->current_freq));
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+
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+ /*
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+ * Make the initial wait an underestimate of how long the transfer
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+ * should take, then poll rapidly to reduce the delay
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+ */
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+ hrtimer_start(&dws->hrtimer,
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+ period * (8 * dws->n_bytes - 1),
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+ HRTIMER_MODE_REL);
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+ dws->idle_wait_retries = 10;
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+ dws->idle_wait_interval = period;
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+ } else {
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+ spi_finalize_current_transfer(dws->host);
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+ }
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+ return IRQ_HANDLED;
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}
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/*
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@@ -255,9 +296,13 @@ static irqreturn_t dw_spi_transfer_handl
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* have the TXE IRQ flood at the final stage of the transfer.
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*/
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if (irq_status & DW_SPI_INT_TXEI) {
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- if (!dws->tx_len)
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- dw_spi_mask_intr(dws, DW_SPI_INT_TXEI);
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dw_writer(dws);
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+ if (!dws->tx_len) {
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+ if (dws->rx_len)
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+ dw_spi_mask_intr(dws, DW_SPI_INT_TXEI);
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+ else
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+ dw_writel(dws, DW_SPI_TXFTLR, 0);
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+ }
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}
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return IRQ_HANDLED;
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@@ -428,7 +473,7 @@ static int dw_spi_poll_transfer(struct d
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ret = dw_spi_check_status(dws, true);
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if (ret)
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return ret;
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- } while (dws->rx_len);
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+ } while (dws->rx_len || dws->tx_len || dw_spi_ctlr_busy(dws));
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return 0;
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}
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@@ -652,11 +697,6 @@ static int dw_spi_write_then_read(struct
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return 0;
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}
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-static inline bool dw_spi_ctlr_busy(struct dw_spi *dws)
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-{
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- return dw_readl(dws, DW_SPI_SR) & DW_SPI_SR_BUSY;
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-}
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-
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static int dw_spi_wait_mem_op_done(struct dw_spi *dws)
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{
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int retry = DW_SPI_WAIT_RETRIES;
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@@ -993,6 +1033,9 @@ int dw_spi_add_host(struct device *dev,
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}
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}
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+ hrtimer_init(&dws->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
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+ dws->hrtimer.function = dw_spi_hrtimer_handler;
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+
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ret = spi_register_controller(host);
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if (ret) {
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dev_err_probe(dev, ret, "problem registering spi host\n");
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@@ -1018,6 +1061,7 @@ void dw_spi_remove_host(struct dw_spi *d
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{
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dw_spi_debugfs_remove(dws);
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+ hrtimer_cancel(&dws->hrtimer);
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spi_unregister_controller(dws->host);
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if (dws->dma_ops && dws->dma_ops->dma_exit)
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--- a/drivers/spi/spi-dw.h
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+++ b/drivers/spi/spi-dw.h
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@@ -180,6 +180,9 @@ struct dw_spi {
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u32 current_freq; /* frequency in hz */
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u32 cur_rx_sample_dly;
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u32 def_rx_sample_dly_ns;
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+ struct hrtimer hrtimer;
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+ ktime_t idle_wait_interval;
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+ int idle_wait_retries;
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/* Custom memory operations */
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struct spi_controller_mem_ops mem_ops;
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