1 files changed, 480 insertions, 0 deletions
diff --git a/drivers/spi/spi-dw-dma.c b/drivers/spi/spi-dw-dma.c
new file mode 100644
index 000000000000..5986c520b196
--- /dev/null
+++ b/drivers/spi/spi-dw-dma.c
@@ -0,0 +1,480 @@
+// 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 WAIT_RETRIES	5
+#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);
+
+	ret = dma_get_slave_caps(dws->txchan, &caps);
+	if (!ret && caps.max_burst)
+		max_burst = caps.max_burst;
+	else
+		max_burst = TX_BURST_LEVEL;
+
+	dws->txburst = min(max_burst, def_burst);
+}
+
+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);
+
+	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);
+
+	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);
+	}
+
+	dw_writel(dws, DW_SPI_DMACR, 0);
+}
+
+static irqreturn_t dw_spi_dma_transfer_handler(struct dw_spi *dws)
+{
+	u16 irq_status = dw_readl(dws, DW_SPI_ISR);
+
+	if (!irq_status)
+		return IRQ_NONE;
+
+	dw_readl(dws, DW_SPI_ICR);
+	spi_reset_chip(dws);
+
+	dev_err(&dws->master->dev, "%s: FIFO overrun/underrun\n", __func__);
+	dws->master->cur_msg->status = -EIO;
+	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, struct spi_transfer *xfer)
+{
+	unsigned long long ms;
+
+	ms = xfer->len * MSEC_PER_SEC * BITS_PER_BYTE;
+	do_div(ms, xfer->effective_speed_hz);
+	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 = 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;
+
+	dw_writel(dws, DW_SPI_DMACR, 0);
+	complete(&dws->dma_completion);
+}
+
+static struct dma_async_tx_descriptor *
+dw_spi_dma_prepare_tx(struct dw_spi *dws, struct spi_transfer *xfer)
+{
+	struct dma_slave_config txconf;
+	struct dma_async_tx_descriptor *txdesc;
+
+	if (!xfer->tx_buf)
+		return NULL;
+
+	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;
+
+	dmaengine_slave_config(dws->txchan, &txconf);
+
+	txdesc = dmaengine_prep_slave_sg(dws->txchan,
+				xfer->tx_sg.sgl,
+				xfer->tx_sg.nents,
+				DMA_MEM_TO_DEV,
+				DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!txdesc)
+		return NULL;
+
+	txdesc->callback = dw_spi_dma_tx_done;
+	txdesc->callback_param = dws;
+
+	return txdesc;
+}
+
+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 = 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;
+
+	dw_writel(dws, DW_SPI_DMACR, 0);
+	complete(&dws->dma_completion);
+}
+
+static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws,
+		struct spi_transfer *xfer)
+{
+	struct dma_slave_config rxconf;
+	struct dma_async_tx_descriptor *rxdesc;
+
+	if (!xfer->rx_buf)
+		return NULL;
+
+	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;
+
+	dmaengine_slave_config(dws->rxchan, &rxconf);
+
+	rxdesc = dmaengine_prep_slave_sg(dws->rxchan,
+				xfer->rx_sg.sgl,
+				xfer->rx_sg.nents,
+				DMA_DEV_TO_MEM,
+				DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!rxdesc)
+		return NULL;
+
+	rxdesc->callback = dw_spi_dma_rx_done;
+	rxdesc->callback_param = dws;
+
+	return rxdesc;
+}
+
+static int dw_spi_dma_setup(struct dw_spi *dws, struct spi_transfer *xfer)
+{
+	u16 imr = 0, dma_ctrl = 0;
+
+	dw_writel(dws, DW_SPI_DMARDLR, dws->rxburst - 1);
+	dw_writel(dws, DW_SPI_DMATDLR, dws->fifo_len - dws->txburst);
+
+	if (xfer->tx_buf)
+		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 */
+	if (xfer->tx_buf)
+		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(struct dw_spi *dws, struct spi_transfer *xfer)
+{
+	struct dma_async_tx_descriptor *txdesc, *rxdesc;
+	int ret;
+
+	/* Prepare the TX dma transfer */
+	txdesc = dw_spi_dma_prepare_tx(dws, xfer);
+
+	/* Prepare the RX dma transfer */
+	rxdesc = dw_spi_dma_prepare_rx(dws, xfer);
+
+	/* rx must be started before tx due to spi instinct */
+	if (rxdesc) {
+		set_bit(RX_BUSY, &dws->dma_chan_busy);
+		dmaengine_submit(rxdesc);
+		dma_async_issue_pending(dws->rxchan);
+	}
+
+	if (txdesc) {
+		set_bit(TX_BUSY, &dws->dma_chan_busy);
+		dmaengine_submit(txdesc);
+		dma_async_issue_pending(dws->txchan);
+	}
+
+	ret = dw_spi_dma_wait(dws, xfer);
+	if (ret)
+		return ret;
+
+	if (txdesc && dws->master->cur_msg->status == -EINPROGRESS) {
+		ret = dw_spi_dma_wait_tx_done(dws, xfer);
+		if (ret)
+			return ret;
+	}
+
+	if (rxdesc && 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);
+	}
+
+	dw_writel(dws, DW_SPI_DMACR, 0);
+}
+
+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);