Update Linux to v5.10.109
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz
Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/drivers/spi/spi-dw-dma.c b/drivers/spi/spi-dw-dma.c
new file mode 100644
index 0000000..a09831c
--- /dev/null
+++ b/drivers/spi/spi-dw-dma.c
@@ -0,0 +1,656 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Special handling for DW DMA core
+ *
+ * Copyright (c) 2009, 2014 Intel Corporation.
+ */
+
+#include <linux/completion.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/irqreturn.h>
+#include <linux/jiffies.h>
+#include <linux/pci.h>
+#include <linux/platform_data/dma-dw.h>
+#include <linux/spi/spi.h>
+#include <linux/types.h>
+
+#include "spi-dw.h"
+
+#define RX_BUSY 0
+#define RX_BURST_LEVEL 16
+#define TX_BUSY 1
+#define TX_BURST_LEVEL 16
+
+static bool dw_spi_dma_chan_filter(struct dma_chan *chan, void *param)
+{
+ struct dw_dma_slave *s = param;
+
+ if (s->dma_dev != chan->device->dev)
+ return false;
+
+ chan->private = s;
+ return true;
+}
+
+static void dw_spi_dma_maxburst_init(struct dw_spi *dws)
+{
+ struct dma_slave_caps caps;
+ u32 max_burst, def_burst;
+ int ret;
+
+ def_burst = dws->fifo_len / 2;
+
+ ret = dma_get_slave_caps(dws->rxchan, &caps);
+ if (!ret && caps.max_burst)
+ max_burst = caps.max_burst;
+ else
+ max_burst = RX_BURST_LEVEL;
+
+ dws->rxburst = min(max_burst, def_burst);
+ dw_writel(dws, DW_SPI_DMARDLR, dws->rxburst - 1);
+
+ ret = dma_get_slave_caps(dws->txchan, &caps);
+ if (!ret && caps.max_burst)
+ max_burst = caps.max_burst;
+ else
+ max_burst = TX_BURST_LEVEL;
+
+ /*
+ * Having a Rx DMA channel serviced with higher priority than a Tx DMA
+ * channel might not be enough to provide a well balanced DMA-based
+ * SPI transfer interface. There might still be moments when the Tx DMA
+ * channel is occasionally handled faster than the Rx DMA channel.
+ * That in its turn will eventually cause the SPI Rx FIFO overflow if
+ * SPI bus speed is high enough to fill the SPI Rx FIFO in before it's
+ * cleared by the Rx DMA channel. In order to fix the problem the Tx
+ * DMA activity is intentionally slowed down by limiting the SPI Tx
+ * FIFO depth with a value twice bigger than the Tx burst length.
+ */
+ dws->txburst = min(max_burst, def_burst);
+ dw_writel(dws, DW_SPI_DMATDLR, dws->txburst);
+}
+
+static void dw_spi_dma_sg_burst_init(struct dw_spi *dws)
+{
+ struct dma_slave_caps tx = {0}, rx = {0};
+
+ dma_get_slave_caps(dws->txchan, &tx);
+ dma_get_slave_caps(dws->rxchan, &rx);
+
+ if (tx.max_sg_burst > 0 && rx.max_sg_burst > 0)
+ dws->dma_sg_burst = min(tx.max_sg_burst, rx.max_sg_burst);
+ else if (tx.max_sg_burst > 0)
+ dws->dma_sg_burst = tx.max_sg_burst;
+ else if (rx.max_sg_burst > 0)
+ dws->dma_sg_burst = rx.max_sg_burst;
+ else
+ dws->dma_sg_burst = 0;
+}
+
+static int dw_spi_dma_init_mfld(struct device *dev, struct dw_spi *dws)
+{
+ struct dw_dma_slave dma_tx = { .dst_id = 1 }, *tx = &dma_tx;
+ struct dw_dma_slave dma_rx = { .src_id = 0 }, *rx = &dma_rx;
+ struct pci_dev *dma_dev;
+ dma_cap_mask_t mask;
+
+ /*
+ * Get pci device for DMA controller, currently it could only
+ * be the DMA controller of Medfield
+ */
+ dma_dev = pci_get_device(PCI_VENDOR_ID_INTEL, 0x0827, NULL);
+ if (!dma_dev)
+ return -ENODEV;
+
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_SLAVE, mask);
+
+ /* 1. Init rx channel */
+ rx->dma_dev = &dma_dev->dev;
+ dws->rxchan = dma_request_channel(mask, dw_spi_dma_chan_filter, rx);
+ if (!dws->rxchan)
+ goto err_exit;
+
+ /* 2. Init tx channel */
+ tx->dma_dev = &dma_dev->dev;
+ dws->txchan = dma_request_channel(mask, dw_spi_dma_chan_filter, tx);
+ if (!dws->txchan)
+ goto free_rxchan;
+
+ dws->master->dma_rx = dws->rxchan;
+ dws->master->dma_tx = dws->txchan;
+
+ init_completion(&dws->dma_completion);
+
+ dw_spi_dma_maxburst_init(dws);
+
+ dw_spi_dma_sg_burst_init(dws);
+
+ return 0;
+
+free_rxchan:
+ dma_release_channel(dws->rxchan);
+ dws->rxchan = NULL;
+err_exit:
+ return -EBUSY;
+}
+
+static int dw_spi_dma_init_generic(struct device *dev, struct dw_spi *dws)
+{
+ dws->rxchan = dma_request_slave_channel(dev, "rx");
+ if (!dws->rxchan)
+ return -ENODEV;
+
+ dws->txchan = dma_request_slave_channel(dev, "tx");
+ if (!dws->txchan) {
+ dma_release_channel(dws->rxchan);
+ dws->rxchan = NULL;
+ return -ENODEV;
+ }
+
+ dws->master->dma_rx = dws->rxchan;
+ dws->master->dma_tx = dws->txchan;
+
+ init_completion(&dws->dma_completion);
+
+ dw_spi_dma_maxburst_init(dws);
+
+ dw_spi_dma_sg_burst_init(dws);
+
+ return 0;
+}
+
+static void dw_spi_dma_exit(struct dw_spi *dws)
+{
+ if (dws->txchan) {
+ dmaengine_terminate_sync(dws->txchan);
+ dma_release_channel(dws->txchan);
+ }
+
+ if (dws->rxchan) {
+ dmaengine_terminate_sync(dws->rxchan);
+ dma_release_channel(dws->rxchan);
+ }
+}
+
+static irqreturn_t dw_spi_dma_transfer_handler(struct dw_spi *dws)
+{
+ dw_spi_check_status(dws, false);
+
+ complete(&dws->dma_completion);
+
+ return IRQ_HANDLED;
+}
+
+static bool dw_spi_can_dma(struct spi_controller *master,
+ struct spi_device *spi, struct spi_transfer *xfer)
+{
+ struct dw_spi *dws = spi_controller_get_devdata(master);
+
+ return xfer->len > dws->fifo_len;
+}
+
+static enum dma_slave_buswidth dw_spi_dma_convert_width(u8 n_bytes)
+{
+ if (n_bytes == 1)
+ return DMA_SLAVE_BUSWIDTH_1_BYTE;
+ else if (n_bytes == 2)
+ return DMA_SLAVE_BUSWIDTH_2_BYTES;
+
+ return DMA_SLAVE_BUSWIDTH_UNDEFINED;
+}
+
+static int dw_spi_dma_wait(struct dw_spi *dws, unsigned int len, u32 speed)
+{
+ unsigned long long ms;
+
+ ms = len * MSEC_PER_SEC * BITS_PER_BYTE;
+ do_div(ms, speed);
+ ms += ms + 200;
+
+ if (ms > UINT_MAX)
+ ms = UINT_MAX;
+
+ ms = wait_for_completion_timeout(&dws->dma_completion,
+ msecs_to_jiffies(ms));
+
+ if (ms == 0) {
+ dev_err(&dws->master->cur_msg->spi->dev,
+ "DMA transaction timed out\n");
+ return -ETIMEDOUT;
+ }
+
+ return 0;
+}
+
+static inline bool dw_spi_dma_tx_busy(struct dw_spi *dws)
+{
+ return !(dw_readl(dws, DW_SPI_SR) & SR_TF_EMPT);
+}
+
+static int dw_spi_dma_wait_tx_done(struct dw_spi *dws,
+ struct spi_transfer *xfer)
+{
+ int retry = SPI_WAIT_RETRIES;
+ struct spi_delay delay;
+ u32 nents;
+
+ nents = dw_readl(dws, DW_SPI_TXFLR);
+ delay.unit = SPI_DELAY_UNIT_SCK;
+ delay.value = nents * dws->n_bytes * BITS_PER_BYTE;
+
+ while (dw_spi_dma_tx_busy(dws) && retry--)
+ spi_delay_exec(&delay, xfer);
+
+ if (retry < 0) {
+ dev_err(&dws->master->dev, "Tx hanged up\n");
+ return -EIO;
+ }
+
+ return 0;
+}
+
+/*
+ * dws->dma_chan_busy is set before the dma transfer starts, callback for tx
+ * channel will clear a corresponding bit.
+ */
+static void dw_spi_dma_tx_done(void *arg)
+{
+ struct dw_spi *dws = arg;
+
+ clear_bit(TX_BUSY, &dws->dma_chan_busy);
+ if (test_bit(RX_BUSY, &dws->dma_chan_busy))
+ return;
+
+ complete(&dws->dma_completion);
+}
+
+static int dw_spi_dma_config_tx(struct dw_spi *dws)
+{
+ struct dma_slave_config txconf;
+
+ memset(&txconf, 0, sizeof(txconf));
+ txconf.direction = DMA_MEM_TO_DEV;
+ txconf.dst_addr = dws->dma_addr;
+ txconf.dst_maxburst = dws->txburst;
+ txconf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ txconf.dst_addr_width = dw_spi_dma_convert_width(dws->n_bytes);
+ txconf.device_fc = false;
+
+ return dmaengine_slave_config(dws->txchan, &txconf);
+}
+
+static int dw_spi_dma_submit_tx(struct dw_spi *dws, struct scatterlist *sgl,
+ unsigned int nents)
+{
+ struct dma_async_tx_descriptor *txdesc;
+ dma_cookie_t cookie;
+ int ret;
+
+ txdesc = dmaengine_prep_slave_sg(dws->txchan, sgl, nents,
+ DMA_MEM_TO_DEV,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ if (!txdesc)
+ return -ENOMEM;
+
+ txdesc->callback = dw_spi_dma_tx_done;
+ txdesc->callback_param = dws;
+
+ cookie = dmaengine_submit(txdesc);
+ ret = dma_submit_error(cookie);
+ if (ret) {
+ dmaengine_terminate_sync(dws->txchan);
+ return ret;
+ }
+
+ set_bit(TX_BUSY, &dws->dma_chan_busy);
+
+ return 0;
+}
+
+static inline bool dw_spi_dma_rx_busy(struct dw_spi *dws)
+{
+ return !!(dw_readl(dws, DW_SPI_SR) & SR_RF_NOT_EMPT);
+}
+
+static int dw_spi_dma_wait_rx_done(struct dw_spi *dws)
+{
+ int retry = SPI_WAIT_RETRIES;
+ struct spi_delay delay;
+ unsigned long ns, us;
+ u32 nents;
+
+ /*
+ * It's unlikely that DMA engine is still doing the data fetching, but
+ * if it's let's give it some reasonable time. The timeout calculation
+ * is based on the synchronous APB/SSI reference clock rate, on a
+ * number of data entries left in the Rx FIFO, times a number of clock
+ * periods normally needed for a single APB read/write transaction
+ * without PREADY signal utilized (which is true for the DW APB SSI
+ * controller).
+ */
+ nents = dw_readl(dws, DW_SPI_RXFLR);
+ ns = 4U * NSEC_PER_SEC / dws->max_freq * nents;
+ if (ns <= NSEC_PER_USEC) {
+ delay.unit = SPI_DELAY_UNIT_NSECS;
+ delay.value = ns;
+ } else {
+ us = DIV_ROUND_UP(ns, NSEC_PER_USEC);
+ delay.unit = SPI_DELAY_UNIT_USECS;
+ delay.value = clamp_val(us, 0, USHRT_MAX);
+ }
+
+ while (dw_spi_dma_rx_busy(dws) && retry--)
+ spi_delay_exec(&delay, NULL);
+
+ if (retry < 0) {
+ dev_err(&dws->master->dev, "Rx hanged up\n");
+ return -EIO;
+ }
+
+ return 0;
+}
+
+/*
+ * dws->dma_chan_busy is set before the dma transfer starts, callback for rx
+ * channel will clear a corresponding bit.
+ */
+static void dw_spi_dma_rx_done(void *arg)
+{
+ struct dw_spi *dws = arg;
+
+ clear_bit(RX_BUSY, &dws->dma_chan_busy);
+ if (test_bit(TX_BUSY, &dws->dma_chan_busy))
+ return;
+
+ complete(&dws->dma_completion);
+}
+
+static int dw_spi_dma_config_rx(struct dw_spi *dws)
+{
+ struct dma_slave_config rxconf;
+
+ memset(&rxconf, 0, sizeof(rxconf));
+ rxconf.direction = DMA_DEV_TO_MEM;
+ rxconf.src_addr = dws->dma_addr;
+ rxconf.src_maxburst = dws->rxburst;
+ rxconf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ rxconf.src_addr_width = dw_spi_dma_convert_width(dws->n_bytes);
+ rxconf.device_fc = false;
+
+ return dmaengine_slave_config(dws->rxchan, &rxconf);
+}
+
+static int dw_spi_dma_submit_rx(struct dw_spi *dws, struct scatterlist *sgl,
+ unsigned int nents)
+{
+ struct dma_async_tx_descriptor *rxdesc;
+ dma_cookie_t cookie;
+ int ret;
+
+ rxdesc = dmaengine_prep_slave_sg(dws->rxchan, sgl, nents,
+ DMA_DEV_TO_MEM,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ if (!rxdesc)
+ return -ENOMEM;
+
+ rxdesc->callback = dw_spi_dma_rx_done;
+ rxdesc->callback_param = dws;
+
+ cookie = dmaengine_submit(rxdesc);
+ ret = dma_submit_error(cookie);
+ if (ret) {
+ dmaengine_terminate_sync(dws->rxchan);
+ return ret;
+ }
+
+ set_bit(RX_BUSY, &dws->dma_chan_busy);
+
+ return 0;
+}
+
+static int dw_spi_dma_setup(struct dw_spi *dws, struct spi_transfer *xfer)
+{
+ u16 imr, dma_ctrl;
+ int ret;
+
+ if (!xfer->tx_buf)
+ return -EINVAL;
+
+ /* Setup DMA channels */
+ ret = dw_spi_dma_config_tx(dws);
+ if (ret)
+ return ret;
+
+ if (xfer->rx_buf) {
+ ret = dw_spi_dma_config_rx(dws);
+ if (ret)
+ return ret;
+ }
+
+ /* Set the DMA handshaking interface */
+ dma_ctrl = SPI_DMA_TDMAE;
+ if (xfer->rx_buf)
+ dma_ctrl |= SPI_DMA_RDMAE;
+ dw_writel(dws, DW_SPI_DMACR, dma_ctrl);
+
+ /* Set the interrupt mask */
+ imr = SPI_INT_TXOI;
+ if (xfer->rx_buf)
+ imr |= SPI_INT_RXUI | SPI_INT_RXOI;
+ spi_umask_intr(dws, imr);
+
+ reinit_completion(&dws->dma_completion);
+
+ dws->transfer_handler = dw_spi_dma_transfer_handler;
+
+ return 0;
+}
+
+static int dw_spi_dma_transfer_all(struct dw_spi *dws,
+ struct spi_transfer *xfer)
+{
+ int ret;
+
+ /* Submit the DMA Tx transfer */
+ ret = dw_spi_dma_submit_tx(dws, xfer->tx_sg.sgl, xfer->tx_sg.nents);
+ if (ret)
+ goto err_clear_dmac;
+
+ /* Submit the DMA Rx transfer if required */
+ if (xfer->rx_buf) {
+ ret = dw_spi_dma_submit_rx(dws, xfer->rx_sg.sgl,
+ xfer->rx_sg.nents);
+ if (ret)
+ goto err_clear_dmac;
+
+ /* rx must be started before tx due to spi instinct */
+ dma_async_issue_pending(dws->rxchan);
+ }
+
+ dma_async_issue_pending(dws->txchan);
+
+ ret = dw_spi_dma_wait(dws, xfer->len, xfer->effective_speed_hz);
+
+err_clear_dmac:
+ dw_writel(dws, DW_SPI_DMACR, 0);
+
+ return ret;
+}
+
+/*
+ * In case if at least one of the requested DMA channels doesn't support the
+ * hardware accelerated SG list entries traverse, the DMA driver will most
+ * likely work that around by performing the IRQ-based SG list entries
+ * resubmission. That might and will cause a problem if the DMA Tx channel is
+ * recharged and re-executed before the Rx DMA channel. Due to
+ * non-deterministic IRQ-handler execution latency the DMA Tx channel will
+ * start pushing data to the SPI bus before the Rx DMA channel is even
+ * reinitialized with the next inbound SG list entry. By doing so the DMA Tx
+ * channel will implicitly start filling the DW APB SSI Rx FIFO up, which while
+ * the DMA Rx channel being recharged and re-executed will eventually be
+ * overflown.
+ *
+ * In order to solve the problem we have to feed the DMA engine with SG list
+ * entries one-by-one. It shall keep the DW APB SSI Tx and Rx FIFOs
+ * synchronized and prevent the Rx FIFO overflow. Since in general the tx_sg
+ * and rx_sg lists may have different number of entries of different lengths
+ * (though total length should match) let's virtually split the SG-lists to the
+ * set of DMA transfers, which length is a minimum of the ordered SG-entries
+ * lengths. An ASCII-sketch of the implemented algo is following:
+ * xfer->len
+ * |___________|
+ * tx_sg list: |___|____|__|
+ * rx_sg list: |_|____|____|
+ * DMA transfers: |_|_|__|_|__|
+ *
+ * Note in order to have this workaround solving the denoted problem the DMA
+ * engine driver should properly initialize the max_sg_burst capability and set
+ * the DMA device max segment size parameter with maximum data block size the
+ * DMA engine supports.
+ */
+
+static int dw_spi_dma_transfer_one(struct dw_spi *dws,
+ struct spi_transfer *xfer)
+{
+ struct scatterlist *tx_sg = NULL, *rx_sg = NULL, tx_tmp, rx_tmp;
+ unsigned int tx_len = 0, rx_len = 0;
+ unsigned int base, len;
+ int ret;
+
+ sg_init_table(&tx_tmp, 1);
+ sg_init_table(&rx_tmp, 1);
+
+ for (base = 0, len = 0; base < xfer->len; base += len) {
+ /* Fetch next Tx DMA data chunk */
+ if (!tx_len) {
+ tx_sg = !tx_sg ? &xfer->tx_sg.sgl[0] : sg_next(tx_sg);
+ sg_dma_address(&tx_tmp) = sg_dma_address(tx_sg);
+ tx_len = sg_dma_len(tx_sg);
+ }
+
+ /* Fetch next Rx DMA data chunk */
+ if (!rx_len) {
+ rx_sg = !rx_sg ? &xfer->rx_sg.sgl[0] : sg_next(rx_sg);
+ sg_dma_address(&rx_tmp) = sg_dma_address(rx_sg);
+ rx_len = sg_dma_len(rx_sg);
+ }
+
+ len = min(tx_len, rx_len);
+
+ sg_dma_len(&tx_tmp) = len;
+ sg_dma_len(&rx_tmp) = len;
+
+ /* Submit DMA Tx transfer */
+ ret = dw_spi_dma_submit_tx(dws, &tx_tmp, 1);
+ if (ret)
+ break;
+
+ /* Submit DMA Rx transfer */
+ ret = dw_spi_dma_submit_rx(dws, &rx_tmp, 1);
+ if (ret)
+ break;
+
+ /* Rx must be started before Tx due to SPI instinct */
+ dma_async_issue_pending(dws->rxchan);
+
+ dma_async_issue_pending(dws->txchan);
+
+ /*
+ * Here we only need to wait for the DMA transfer to be
+ * finished since SPI controller is kept enabled during the
+ * procedure this loop implements and there is no risk to lose
+ * data left in the Tx/Rx FIFOs.
+ */
+ ret = dw_spi_dma_wait(dws, len, xfer->effective_speed_hz);
+ if (ret)
+ break;
+
+ reinit_completion(&dws->dma_completion);
+
+ sg_dma_address(&tx_tmp) += len;
+ sg_dma_address(&rx_tmp) += len;
+ tx_len -= len;
+ rx_len -= len;
+ }
+
+ dw_writel(dws, DW_SPI_DMACR, 0);
+
+ return ret;
+}
+
+static int dw_spi_dma_transfer(struct dw_spi *dws, struct spi_transfer *xfer)
+{
+ unsigned int nents;
+ int ret;
+
+ nents = max(xfer->tx_sg.nents, xfer->rx_sg.nents);
+
+ /*
+ * Execute normal DMA-based transfer (which submits the Rx and Tx SG
+ * lists directly to the DMA engine at once) if either full hardware
+ * accelerated SG list traverse is supported by both channels, or the
+ * Tx-only SPI transfer is requested, or the DMA engine is capable to
+ * handle both SG lists on hardware accelerated basis.
+ */
+ if (!dws->dma_sg_burst || !xfer->rx_buf || nents <= dws->dma_sg_burst)
+ ret = dw_spi_dma_transfer_all(dws, xfer);
+ else
+ ret = dw_spi_dma_transfer_one(dws, xfer);
+ if (ret)
+ return ret;
+
+ if (dws->master->cur_msg->status == -EINPROGRESS) {
+ ret = dw_spi_dma_wait_tx_done(dws, xfer);
+ if (ret)
+ return ret;
+ }
+
+ if (xfer->rx_buf && dws->master->cur_msg->status == -EINPROGRESS)
+ ret = dw_spi_dma_wait_rx_done(dws);
+
+ return ret;
+}
+
+static void dw_spi_dma_stop(struct dw_spi *dws)
+{
+ if (test_bit(TX_BUSY, &dws->dma_chan_busy)) {
+ dmaengine_terminate_sync(dws->txchan);
+ clear_bit(TX_BUSY, &dws->dma_chan_busy);
+ }
+ if (test_bit(RX_BUSY, &dws->dma_chan_busy)) {
+ dmaengine_terminate_sync(dws->rxchan);
+ clear_bit(RX_BUSY, &dws->dma_chan_busy);
+ }
+}
+
+static const struct dw_spi_dma_ops dw_spi_dma_mfld_ops = {
+ .dma_init = dw_spi_dma_init_mfld,
+ .dma_exit = dw_spi_dma_exit,
+ .dma_setup = dw_spi_dma_setup,
+ .can_dma = dw_spi_can_dma,
+ .dma_transfer = dw_spi_dma_transfer,
+ .dma_stop = dw_spi_dma_stop,
+};
+
+void dw_spi_dma_setup_mfld(struct dw_spi *dws)
+{
+ dws->dma_ops = &dw_spi_dma_mfld_ops;
+}
+EXPORT_SYMBOL_GPL(dw_spi_dma_setup_mfld);
+
+static const struct dw_spi_dma_ops dw_spi_dma_generic_ops = {
+ .dma_init = dw_spi_dma_init_generic,
+ .dma_exit = dw_spi_dma_exit,
+ .dma_setup = dw_spi_dma_setup,
+ .can_dma = dw_spi_can_dma,
+ .dma_transfer = dw_spi_dma_transfer,
+ .dma_stop = dw_spi_dma_stop,
+};
+
+void dw_spi_dma_setup_generic(struct dw_spi *dws)
+{
+ dws->dma_ops = &dw_spi_dma_generic_ops;
+}
+EXPORT_SYMBOL_GPL(dw_spi_dma_setup_generic);