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Subject[PATCH v5] spi: spi-geni-qcom: Add support for GPI dma
Date
We can use GPI DMA for devices where it is enabled by firmware. Add
support for this mode

Signed-off-by: Vinod Koul <vkoul@kernel.org>
--
-Changes since v4:
- Fix the kbuild bot warning

-Changes since v3:
- Drop merged spi core, geni patches
- Remove global structs and use local variables instead
- modularize code more as suggested by Doug
- fix kbuild bot warning

drivers/spi/spi-geni-qcom.c | 254 +++++++++++++++++++++++++++++++++---
1 file changed, 239 insertions(+), 15 deletions(-)

diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c
index 2f51421e2a71..27a446faf143 100644
--- a/drivers/spi/spi-geni-qcom.c
+++ b/drivers/spi/spi-geni-qcom.c
@@ -2,6 +2,9 @@
// Copyright (c) 2017-2018, The Linux foundation. All rights reserved.

#include <linux/clk.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/dma/qcom-gpi-dma.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/log2.h>
@@ -63,6 +66,15 @@
#define TIMESTAMP_AFTER BIT(3)
#define POST_CMD_DELAY BIT(4)

+#define GSI_LOOPBACK_EN BIT(0)
+#define GSI_CS_TOGGLE BIT(3)
+#define GSI_CPHA BIT(4)
+#define GSI_CPOL BIT(5)
+
+#define MAX_TX_SG 3
+#define NUM_SPI_XFER 8
+#define SPI_XFER_TIMEOUT_MS 250
+
struct spi_geni_master {
struct geni_se se;
struct device *dev;
@@ -84,6 +96,9 @@ struct spi_geni_master {
int irq;
bool cs_flag;
bool abort_failed;
+ struct dma_chan *tx;
+ struct dma_chan *rx;
+ int cur_xfer_mode;
};

static int get_spi_clk_cfg(unsigned int speed_hz,
@@ -330,34 +345,197 @@ static int setup_fifo_params(struct spi_device *spi_slv,
return geni_spi_set_clock_and_bw(mas, spi_slv->max_speed_hz);
}

+static void
+spi_gsi_callback_result(void *cb, const struct dmaengine_result *result)
+{
+ struct spi_master *spi = cb;
+
+ if (result->result != DMA_TRANS_NOERROR) {
+ dev_err(&spi->dev, "DMA txn failed: %d\n", result->result);
+ return;
+ }
+
+ if (!result->residue) {
+ dev_dbg(&spi->dev, "DMA txn completed\n");
+ spi_finalize_current_transfer(spi);
+ } else {
+ dev_err(&spi->dev, "DMA xfer has pending: %d\n", result->residue);
+ }
+}
+
+static int setup_gsi_xfer(struct spi_transfer *xfer, struct spi_geni_master *mas,
+ struct spi_device *spi_slv, struct spi_master *spi)
+{
+ unsigned long flags = DMA_PREP_INTERRUPT | DMA_CTRL_ACK;
+ struct dma_slave_config config = {};
+ struct gpi_spi_config peripheral = {};
+ struct dma_async_tx_descriptor *tx_desc, *rx_desc;
+ int ret;
+
+ config.peripheral_config = &peripheral;
+ config.peripheral_size = sizeof(peripheral);
+ peripheral.set_config = true;
+
+ if (xfer->bits_per_word != mas->cur_bits_per_word ||
+ xfer->speed_hz != mas->cur_speed_hz) {
+ mas->cur_bits_per_word = xfer->bits_per_word;
+ mas->cur_speed_hz = xfer->speed_hz;
+ }
+
+ if (xfer->tx_buf && xfer->rx_buf) {
+ peripheral.cmd = SPI_DUPLEX;
+ } else if (xfer->tx_buf) {
+ peripheral.cmd = SPI_TX;
+ peripheral.rx_len = 0;
+ } else if (xfer->rx_buf) {
+ peripheral.cmd = SPI_RX;
+ if (!(mas->cur_bits_per_word % MIN_WORD_LEN)) {
+ peripheral.rx_len = ((xfer->len << 3) / mas->cur_bits_per_word);
+ } else {
+ int bytes_per_word = (mas->cur_bits_per_word / BITS_PER_BYTE) + 1;
+
+ peripheral.rx_len = (xfer->len / bytes_per_word);
+ }
+ }
+
+ peripheral.loopback_en = !!(spi_slv->mode & SPI_LOOP);
+ peripheral.clock_pol_high = !!(spi_slv->mode & SPI_CPOL);
+ peripheral.data_pol_high = !!(spi_slv->mode & SPI_CPHA);
+ peripheral.cs = spi_slv->chip_select;
+ peripheral.pack_en = true;
+ peripheral.word_len = xfer->bits_per_word - MIN_WORD_LEN;
+
+ ret = get_spi_clk_cfg(mas->cur_speed_hz, mas,
+ &peripheral.clk_src, &peripheral.clk_div);
+ if (ret) {
+ dev_err(mas->dev, "Err in get_spi_clk_cfg() :%d\n", ret);
+ return ret;
+ }
+
+ if (!xfer->cs_change) {
+ if (!list_is_last(&xfer->transfer_list, &spi->cur_msg->transfers))
+ peripheral.fragmentation = FRAGMENTATION;
+ }
+
+ if (peripheral.cmd & SPI_RX) {
+ dmaengine_slave_config(mas->rx, &config);
+ rx_desc = dmaengine_prep_slave_sg(mas->rx, xfer->rx_sg.sgl, xfer->rx_sg.nents,
+ DMA_DEV_TO_MEM, flags);
+ if (!rx_desc) {
+ dev_err(mas->dev, "Err setting up rx desc\n");
+ return -EIO;
+ }
+ }
+
+ /*
+ * Prepare the TX always, even for RX or tx_buf being null, we would
+ * need TX to be prepared per GSI spec
+ */
+ dmaengine_slave_config(mas->tx, &config);
+ tx_desc = dmaengine_prep_slave_sg(mas->tx, xfer->tx_sg.sgl, xfer->tx_sg.nents,
+ DMA_MEM_TO_DEV, flags);
+ if (!tx_desc) {
+ dev_err(mas->dev, "Err setting up tx desc\n");
+ return -EIO;
+ }
+
+ tx_desc->callback_result = spi_gsi_callback_result;
+ tx_desc->callback_param = spi;
+
+ if (peripheral.cmd & SPI_RX)
+ dmaengine_submit(rx_desc);
+ dmaengine_submit(tx_desc);
+
+ if (peripheral.cmd & SPI_RX)
+ dma_async_issue_pending(mas->rx);
+
+ dma_async_issue_pending(mas->tx);
+ return 1;
+}
+
+static bool geni_can_dma(struct spi_controller *ctlr,
+ struct spi_device *slv, struct spi_transfer *xfer)
+{
+ struct spi_geni_master *mas = spi_master_get_devdata(slv->master);
+
+ /* check if dma is supported */
+ return mas->cur_xfer_mode != GENI_SE_FIFO;
+}
+
static int spi_geni_prepare_message(struct spi_master *spi,
struct spi_message *spi_msg)
{
- int ret;
struct spi_geni_master *mas = spi_master_get_devdata(spi);
+ int ret;

- if (spi_geni_is_abort_still_pending(mas))
- return -EBUSY;
+ switch (mas->cur_xfer_mode) {
+ case GENI_SE_FIFO:
+ if (spi_geni_is_abort_still_pending(mas))
+ return -EBUSY;
+ ret = setup_fifo_params(spi_msg->spi, spi);
+ if (ret)
+ dev_err(mas->dev, "Couldn't select mode %d\n", ret);
+ return ret;

- ret = setup_fifo_params(spi_msg->spi, spi);
- if (ret)
- dev_err(mas->dev, "Couldn't select mode %d\n", ret);
+ case GENI_GPI_DMA:
+ /* nothing to do for GPI DMA */
+ return 0;
+ }
+
+ dev_err(mas->dev, "Mode not supported %d", mas->cur_xfer_mode);
+ return -EINVAL;
+}
+
+static int spi_geni_grab_gpi_chan(struct spi_geni_master *mas)
+{
+ int ret;
+
+ mas->tx = dma_request_chan(mas->dev, "tx");
+ ret = dev_err_probe(mas->dev, IS_ERR(mas->tx), "Failed to get tx DMA ch\n");
+ if (ret < 0)
+ goto err_tx;
+
+ mas->rx = dma_request_chan(mas->dev, "rx");
+ ret = dev_err_probe(mas->dev, IS_ERR(mas->rx), "Failed to get rx DMA ch\n");
+ if (ret < 0)
+ goto err_rx;
+
+ return 0;
+
+err_rx:
+ dma_release_channel(mas->tx);
+ mas->tx = NULL;
+err_tx:
+ mas->rx = NULL;
return ret;
}

+static void spi_geni_release_dma_chan(struct spi_geni_master *mas)
+{
+ if (mas->rx) {
+ dma_release_channel(mas->rx);
+ mas->rx = NULL;
+ }
+
+ if (mas->tx) {
+ dma_release_channel(mas->tx);
+ mas->tx = NULL;
+ }
+}
+
static int spi_geni_init(struct spi_geni_master *mas)
{
struct geni_se *se = &mas->se;
unsigned int proto, major, minor, ver;
- u32 spi_tx_cfg;
+ u32 spi_tx_cfg, fifo_disable;
+ int ret = -ENXIO;

pm_runtime_get_sync(mas->dev);

proto = geni_se_read_proto(se);
if (proto != GENI_SE_SPI) {
dev_err(mas->dev, "Invalid proto %d\n", proto);
- pm_runtime_put(mas->dev);
- return -ENXIO;
+ goto out_pm;
}
mas->tx_fifo_depth = geni_se_get_tx_fifo_depth(se);

@@ -380,15 +558,38 @@ static int spi_geni_init(struct spi_geni_master *mas)
else
mas->oversampling = 1;

- geni_se_select_mode(se, GENI_SE_FIFO);
+ fifo_disable = readl(se->base + GENI_IF_DISABLE_RO) & FIFO_IF_DISABLE;
+ switch (fifo_disable) {
+ case 1:
+ ret = spi_geni_grab_gpi_chan(mas);
+ if (!ret) { /* success case */
+ mas->cur_xfer_mode = GENI_GPI_DMA;
+ geni_se_select_mode(se, GENI_GPI_DMA);
+ dev_dbg(mas->dev, "Using GPI DMA mode for SPI\n");
+ break;
+ }
+ /*
+ * in case of failure to get dma channel, we can still do the
+ * FIFO mode, so fallthrough
+ */
+ dev_warn(mas->dev, "FIFO mode disabled, but couldn't get DMA, fall back to FIFO mode\n");
+ fallthrough;
+
+ case 0:
+ mas->cur_xfer_mode = GENI_SE_FIFO;
+ geni_se_select_mode(se, GENI_SE_FIFO);
+ ret = 0;
+ break;
+ }

/* We always control CS manually */
spi_tx_cfg = readl(se->base + SE_SPI_TRANS_CFG);
spi_tx_cfg &= ~CS_TOGGLE;
writel(spi_tx_cfg, se->base + SE_SPI_TRANS_CFG);

+out_pm:
pm_runtime_put(mas->dev);
- return 0;
+ return ret;
}

static unsigned int geni_byte_per_fifo_word(struct spi_geni_master *mas)
@@ -569,8 +770,11 @@ static int spi_geni_transfer_one(struct spi_master *spi,
if (!xfer->len)
return 0;

- setup_fifo_xfer(xfer, mas, slv->mode, spi);
- return 1;
+ if (mas->cur_xfer_mode == GENI_SE_FIFO) {
+ setup_fifo_xfer(xfer, mas, slv->mode, spi);
+ return 1;
+ }
+ return setup_gsi_xfer(xfer, mas, slv, spi);
}

static irqreturn_t geni_spi_isr(int irq, void *data)
@@ -665,6 +869,13 @@ static int spi_geni_probe(struct platform_device *pdev)
if (irq < 0)
return irq;

+ ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
+ if (ret) {
+ ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
+ if (ret)
+ return dev_err_probe(dev, ret, "could not set DMA mask\n");
+ }
+
base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(base))
return PTR_ERR(base);
@@ -704,9 +915,10 @@ static int spi_geni_probe(struct platform_device *pdev)
spi->max_speed_hz = 50000000;
spi->prepare_message = spi_geni_prepare_message;
spi->transfer_one = spi_geni_transfer_one;
+ spi->can_dma = geni_can_dma;
+ spi->dma_map_dev = dev->parent;
spi->auto_runtime_pm = true;
spi->handle_err = handle_fifo_timeout;
- spi->set_cs = spi_geni_set_cs;
spi->use_gpio_descriptors = true;

init_completion(&mas->cs_done);
@@ -732,9 +944,17 @@ static int spi_geni_probe(struct platform_device *pdev)
if (ret)
goto spi_geni_probe_runtime_disable;

+ /*
+ * check the mode supported and set_cs for fifo mode only
+ * for dma (gsi) mode, the gsi will set cs based on params passed in
+ * TRE
+ */
+ if (mas->cur_xfer_mode == GENI_SE_FIFO)
+ spi->set_cs = spi_geni_set_cs;
+
ret = request_irq(mas->irq, geni_spi_isr, 0, dev_name(dev), spi);
if (ret)
- goto spi_geni_probe_runtime_disable;
+ goto spi_geni_release_dma;

ret = spi_register_master(spi);
if (ret)
@@ -743,6 +963,8 @@ static int spi_geni_probe(struct platform_device *pdev)
return 0;
spi_geni_probe_free_irq:
free_irq(mas->irq, spi);
+spi_geni_release_dma:
+ spi_geni_release_dma_chan(mas);
spi_geni_probe_runtime_disable:
pm_runtime_disable(dev);
return ret;
@@ -756,6 +978,8 @@ static int spi_geni_remove(struct platform_device *pdev)
/* Unregister _before_ disabling pm_runtime() so we stop transfers */
spi_unregister_master(spi);

+ spi_geni_release_dma_chan(mas);
+
free_irq(mas->irq, spi);
pm_runtime_disable(&pdev->dev);
return 0;
--
2.31.1
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