[PATCH 4/7] spi: spi-geni-qcom: Add support for GPI dma

Vinod Koul
2021-01-11T15:18:33Z

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>
---
drivers/spi/spi-geni-qcom.c | 395 +++++++++++++++++++++++++++++++++++-
1 file changed, 384 insertions(+), 11 deletions(-)

diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c
index 512e925d5ea4..5bb0e2192734 100644
--- a/drivers/spi/spi-geni-qcom.c
+++ b/drivers/spi/spi-geni-qcom.c
@@ -2,6 +2,8 @@
// 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/interrupt.h>
#include <linux/io.h>
#include <linux/log2.h>
@@ -10,6 +12,7 @@
#include <linux/pm_opp.h>
#include <linux/pm_runtime.h>
#include <linux/qcom-geni-se.h>
+#include <linux/dma/qcom-gpi-dma.h>
#include <linux/spi/spi.h>
#include <linux/spinlock.h>

@@ -63,6 +66,35 @@
#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 gsi_desc_cb {
+ struct spi_geni_master *mas;
+ struct spi_transfer *xfer;
+};
+
+struct spi_geni_gsi {
+ dma_cookie_t tx_cookie;
+ dma_cookie_t rx_cookie;
+ struct dma_async_tx_descriptor *tx_desc;
+ struct dma_async_tx_descriptor *rx_desc;
+ struct gsi_desc_cb desc_cb;
+};
+
+enum spi_m_cmd_opcode {
+ CMD_NONE,
+ CMD_XFER,
+ CMD_CS,
+ CMD_CANCEL,
+};
+
struct spi_geni_master {
struct geni_se se;
struct device *dev;
@@ -79,10 +111,21 @@ struct spi_geni_master {
struct completion cs_done;
struct completion cancel_done;
struct completion abort_done;
+ struct completion xfer_done;
unsigned int oversampling;
spinlock_t lock;
int irq;
bool cs_flag;
+ struct spi_geni_gsi *gsi;
+ struct dma_chan *tx;
+ struct dma_chan *rx;
+ struct completion tx_cb;
+ struct completion rx_cb;
+ bool qn_err;
+ int cur_xfer_mode;
+ int num_tx_eot;
+ int num_rx_eot;
+ int num_xfers;
};

static int get_spi_clk_cfg(unsigned int speed_hz,
@@ -274,31 +317,269 @@ static int setup_fifo_params(struct spi_device *spi_slv,
return geni_spi_set_clock_and_bw(mas, spi_slv->max_speed_hz);
}

+static int get_xfer_mode(struct spi_master *spi)
+{
+ struct spi_geni_master *mas = spi_master_get_devdata(spi);
+ struct geni_se *se = &mas->se;
+ int mode = GENI_SE_FIFO;
+ int fifo_disable;
+ bool dma_chan_valid;
+
+ fifo_disable = readl(se->base + GENI_IF_DISABLE_RO) & FIFO_IF_DISABLE;
+ dma_chan_valid = !(IS_ERR_OR_NULL(mas->tx) || IS_ERR_OR_NULL(mas->rx));
+
+ /*
+ * If FIFO Interface is disabled and there are no DMA channels then we
+ * can't do this transfer.
+ * If FIFO interface is disabled, we can do GSI only,
+ * else pick FIFO mode.
+ */
+ if (fifo_disable && !dma_chan_valid) {
+ dev_err(mas->dev, "Fifo and dma mode disabled!! can't xfer\n");
+ mode = -EINVAL;
+ } else if (fifo_disable) {
+ mode = GENI_GPI_DMA;
+ } else {
+ mode = GENI_SE_FIFO;
+ }
+
+ return mode;
+}
+
+static void
+spi_gsi_callback_result(void *cb, const struct dmaengine_result *result, bool tx)
+{
+ struct gsi_desc_cb *gsi = cb;
+
+ if (result->result != DMA_TRANS_NOERROR) {
+ dev_err(gsi->mas->dev, "%s: DMA %s txn failed\n", __func__, tx ? "tx" : "rx");
+ return;
+ }
+
+ if (!result->residue) {
+ dev_dbg(gsi->mas->dev, "%s\n", __func__);
+ if (tx)
+ complete(&gsi->mas->tx_cb);
+ else
+ complete(&gsi->mas->rx_cb);
+ } else {
+ dev_err(gsi->mas->dev, "DMA xfer has pending: %d\n", result->residue);
+ }
+}
+
+static void
+spi_gsi_rx_callback_result(void *cb, const struct dmaengine_result *result)
+{
+ spi_gsi_callback_result(cb, result, false);
+}
+
+static void
+spi_gsi_tx_callback_result(void *cb, const struct dmaengine_result *result)
+{
+ spi_gsi_callback_result(cb, result, true);
+}
+
+static int setup_gsi_xfer(struct spi_transfer *xfer, struct spi_geni_master *mas,
+ struct spi_device *spi_slv, struct spi_master *spi)
+{
+ int ret = 0;
+ unsigned long flags = DMA_PREP_INTERRUPT | DMA_CTRL_ACK;
+ struct spi_geni_gsi *gsi;
+ struct dma_slave_config config;
+ struct gpi_spi_config peripheral;
+
+ memset(&config, 0, sizeof(config));
+ memset(&peripheral, 0, sizeof(peripheral));
+ config.peripheral_config = &peripheral;
+ config.peripheral_size = sizeof(peripheral);
+
+ 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;
+ peripheral.set_config = true;
+ }
+
+ 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);
+ }
+
+ 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;
+ }
+
+ peripheral.cs = spi_slv->chip_select;
+
+ if (spi_slv->mode & SPI_LOOP)
+ peripheral.loopback_en = true;
+ if (spi_slv->mode & SPI_CPOL)
+ peripheral.clock_pol_high = true;
+ if (spi_slv->mode & SPI_CPHA)
+ peripheral.data_pol_high = true;
+ 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, "%s:Err setting clks:%d\n", __func__, ret);
+ return ret;
+ }
+
+ if (!xfer->cs_change) {
+ if (!list_is_last(&xfer->transfer_list, &spi->cur_msg->transfers))
+ peripheral.fragmentation = FRAGMENTATION;
+ }
+
+ gsi = &mas->gsi[mas->num_xfers];
+ gsi->desc_cb.mas = mas;
+ gsi->desc_cb.xfer = xfer;
+ if (peripheral.cmd & SPI_RX) {
+ dmaengine_slave_config(mas->rx, &config);
+ gsi->rx_desc = dmaengine_prep_slave_single(mas->rx, xfer->rx_dma,
+ xfer->len, DMA_DEV_TO_MEM, flags);
+ if (IS_ERR_OR_NULL(gsi->rx_desc)) {
+ dev_err(mas->dev, "Err setting up rx desc\n");
+ return -EIO;
+ }
+ gsi->rx_desc->callback_result = spi_gsi_rx_callback_result;
+ gsi->rx_desc->callback_param = &gsi->desc_cb;
+ mas->num_rx_eot++;
+ }
+
+ if (peripheral.cmd & SPI_TX_ONLY)
+ mas->num_tx_eot++;
+
+ dmaengine_slave_config(mas->tx, &config);
+ gsi->tx_desc = dmaengine_prep_slave_single(mas->tx, xfer->tx_dma,
+ xfer->len, DMA_MEM_TO_DEV, flags);
+
+ if (IS_ERR_OR_NULL(gsi->tx_desc)) {
+ dev_err(mas->dev, "Err setting up tx desc\n");
+ return -EIO;
+ }
+ gsi->tx_desc->callback_result = spi_gsi_tx_callback_result;
+ gsi->tx_desc->callback_param = &gsi->desc_cb;
+ if (peripheral.cmd & SPI_RX)
+ gsi->rx_cookie = dmaengine_submit(gsi->rx_desc);
+ gsi->tx_cookie = dmaengine_submit(gsi->tx_desc);
+ if (peripheral.cmd & SPI_RX)
+ dma_async_issue_pending(mas->rx);
+ dma_async_issue_pending(mas->tx);
+ mas->num_xfers++;
+ return ret;
+}
+
+static int spi_geni_map_buf(struct spi_geni_master *mas, struct spi_message *msg)
+{
+ struct spi_transfer *xfer;
+ struct device *gsi_dev = mas->dev->parent;
+
+ list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+ if (xfer->rx_buf) {
+ xfer->rx_dma = dma_map_single(gsi_dev, xfer->rx_buf,
+ xfer->len, DMA_FROM_DEVICE);
+ if (dma_mapping_error(mas->dev, xfer->rx_dma)) {
+ dev_err(mas->dev, "Err mapping buf\n");
+ return -ENOMEM;
+ }
+ }
+
+ if (xfer->tx_buf) {
+ xfer->tx_dma = dma_map_single(gsi_dev, (void *)xfer->tx_buf,
+ xfer->len, DMA_TO_DEVICE);
+ if (dma_mapping_error(gsi_dev, xfer->tx_dma)) {
+ dev_err(mas->dev, "Err mapping buf\n");
+ dma_unmap_single(gsi_dev, xfer->rx_dma, xfer->len, DMA_FROM_DEVICE);
+ return -ENOMEM;
+ }
+ }
+ };
+
+ return 0;
+}
+
+static void spi_geni_unmap_buf(struct spi_geni_master *mas, struct spi_message *msg)
+{
+ struct spi_transfer *xfer;
+ struct device *gsi_dev = mas->dev;
+
+ list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+ if (xfer->rx_buf)
+ dma_unmap_single(gsi_dev, xfer->rx_dma, xfer->len, DMA_FROM_DEVICE);
+ if (xfer->tx_buf)
+ dma_unmap_single(gsi_dev, xfer->tx_dma, xfer->len, DMA_TO_DEVICE);
+ };
+}
+
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);
+ struct geni_se *se = &mas->se;
+
+ mas->cur_xfer_mode = get_xfer_mode(spi);
+
+ if (mas->cur_xfer_mode == GENI_SE_FIFO) {
+ geni_se_select_mode(se, GENI_SE_FIFO);
+ reinit_completion(&mas->xfer_done);
+ ret = setup_fifo_params(spi_msg->spi, spi);
+ if (ret)
+ dev_err(mas->dev, "Couldn't select mode %d\n", ret);
+
+ } else if (mas->cur_xfer_mode == GENI_GPI_DMA) {
+ mas->num_tx_eot = 0;
+ mas->num_rx_eot = 0;
+ mas->num_xfers = 0;
+ reinit_completion(&mas->tx_cb);
+ reinit_completion(&mas->rx_cb);
+ memset(mas->gsi, 0, (sizeof(struct spi_geni_gsi) * NUM_SPI_XFER));
+ geni_se_select_mode(se, GENI_GPI_DMA);
+ ret = spi_geni_map_buf(mas, spi_msg);
+
+ } else {
+ dev_err(mas->dev, "%s: Couldn't select mode %d", __func__, mas->cur_xfer_mode);
+ ret = -EINVAL;
+ }

- ret = setup_fifo_params(spi_msg->spi, spi);
- if (ret)
- dev_err(mas->dev, "Couldn't select mode %d\n", ret);
return ret;
}

+static int spi_geni_unprepare_message(struct spi_master *spi_mas, struct spi_message *spi_msg)
+{
+ struct spi_geni_master *mas = spi_master_get_devdata(spi_mas);
+
+ mas->cur_speed_hz = 0;
+ mas->cur_bits_per_word = 0;
+ if (mas->cur_xfer_mode == GENI_GPI_DMA)
+ spi_geni_unmap_buf(mas, spi_msg);
+ return 0;
+}
+
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;
+ size_t gsi_sz;
+ int ret = 0;

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;
+ ret = -ENXIO;
+ goto out_pm;
}
mas->tx_fifo_depth = geni_se_get_tx_fifo_depth(se);

@@ -328,8 +609,34 @@ static int spi_geni_init(struct spi_geni_master *mas)
spi_tx_cfg &= ~CS_TOGGLE;
writel(spi_tx_cfg, se->base + SE_SPI_TRANS_CFG);

+ mas->tx = dma_request_slave_channel(mas->dev, "tx");
+ if (IS_ERR_OR_NULL(mas->tx)) {
+ dev_err(mas->dev, "Failed to get tx DMA ch %ld", PTR_ERR(mas->tx));
+ ret = PTR_ERR(mas->tx);
+ goto out_pm;
+ } else {
+ mas->rx = dma_request_slave_channel(mas->dev, "rx");
+ if (IS_ERR_OR_NULL(mas->rx)) {
+ dev_err(mas->dev, "Failed to get rx DMA ch %ld", PTR_ERR(mas->rx));
+ dma_release_channel(mas->tx);
+ ret = PTR_ERR(mas->rx);
+ goto out_pm;
+ }
+
+ gsi_sz = sizeof(struct spi_geni_gsi) * NUM_SPI_XFER;
+ mas->gsi = devm_kzalloc(mas->dev, gsi_sz, GFP_KERNEL);
+ if (IS_ERR_OR_NULL(mas->gsi)) {
+ dma_release_channel(mas->tx);
+ dma_release_channel(mas->rx);
+ mas->tx = NULL;
+ mas->rx = NULL;
+ goto out_pm;
+ }
+ }
+
+out_pm:
pm_runtime_put(mas->dev);
- return 0;
+ return ret;
}

static unsigned int geni_byte_per_fifo_word(struct spi_geni_master *mas)
@@ -420,6 +727,7 @@ static void setup_fifo_xfer(struct spi_transfer *xfer,
{
u32 m_cmd = 0;
u32 len;
+ u32 m_param = 0;
struct geni_se *se = &mas->se;
int ret;

@@ -457,6 +765,11 @@ static void setup_fifo_xfer(struct spi_transfer *xfer,
len = xfer->len / (mas->cur_bits_per_word / BITS_PER_BYTE + 1);
len &= TRANS_LEN_MSK;

+ if (!xfer->cs_change) {
+ if (!list_is_last(&xfer->transfer_list, &spi->cur_msg->transfers))
+ m_param |= FRAGMENTATION;
+ }
+
mas->cur_xfer = xfer;
if (xfer->tx_buf) {
m_cmd |= SPI_TX_ONLY;
@@ -475,7 +788,7 @@ static void setup_fifo_xfer(struct spi_transfer *xfer,
* interrupt could come in at any time now.
*/
spin_lock_irq(&mas->lock);
- geni_se_setup_m_cmd(se, m_cmd, FRAGMENTATION);
+ geni_se_setup_m_cmd(se, m_cmd, m_param);

/*
* TX_WATERMARK_REG should be set after SPI configuration and
@@ -494,13 +807,52 @@ static int spi_geni_transfer_one(struct spi_master *spi,
struct spi_transfer *xfer)
{
struct spi_geni_master *mas = spi_master_get_devdata(spi);
+ unsigned long timeout, jiffies;
+ int ret = 0i, i;

/* Terminate and return success for 0 byte length transfer */
if (!xfer->len)
- return 0;
+ return ret;
+
+ if (mas->cur_xfer_mode == GENI_SE_FIFO) {
+ setup_fifo_xfer(xfer, mas, slv->mode, spi);
+ } else {
+ setup_gsi_xfer(xfer, mas, slv, spi);
+ if (mas->num_xfers >= NUM_SPI_XFER ||
+ (list_is_last(&xfer->transfer_list, &spi->cur_msg->transfers))) {
+ for (i = 0 ; i < mas->num_tx_eot; i++) {
+ jiffies = msecs_to_jiffies(SPI_XFER_TIMEOUT_MS);
+ timeout = wait_for_completion_timeout(&mas->tx_cb, jiffies);
+ if (timeout <= 0) {
+ dev_err(mas->dev, "Tx[%d] timeout%lu\n", i, timeout);
+ ret = -ETIMEDOUT;
+ goto err_gsi_geni_transfer_one;
+ }
+ spi_finalize_current_transfer(spi);
+ }
+ for (i = 0 ; i < mas->num_rx_eot; i++) {
+ jiffies = msecs_to_jiffies(SPI_XFER_TIMEOUT_MS);
+ timeout = wait_for_completion_timeout(&mas->tx_cb, jiffies);
+ if (timeout <= 0) {
+ dev_err(mas->dev, "Rx[%d] timeout%lu\n", i, timeout);
+ ret = -ETIMEDOUT;
+ goto err_gsi_geni_transfer_one;
+ }
+ spi_finalize_current_transfer(spi);
+ }
+ if (mas->qn_err) {
+ ret = -EIO;
+ mas->qn_err = false;
+ goto err_gsi_geni_transfer_one;
+ }
+ }
+ }

- setup_fifo_xfer(xfer, mas, slv->mode, spi);
- return 1;
+ return ret;
+
+err_gsi_geni_transfer_one:
+ dmaengine_terminate_all(mas->tx);
+ return ret;
}

static irqreturn_t geni_spi_isr(int irq, void *data)
@@ -595,6 +947,15 @@ static int spi_geni_probe(struct platform_device *pdev)
if (irq < 0)
return irq;

+ ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
+ if (ret) {
+ ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+ if (ret) {
+ dev_err(&pdev->dev, "could not set DMA mask\n");
+ return ret;
+ }
+ }
+
base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(base))
return PTR_ERR(base);
@@ -632,15 +993,18 @@ static int spi_geni_probe(struct platform_device *pdev)
spi->num_chipselect = 4;
spi->max_speed_hz = 50000000;
spi->prepare_message = spi_geni_prepare_message;
+ spi->unprepare_message = spi_geni_unprepare_message;
spi->transfer_one = spi_geni_transfer_one;
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);
init_completion(&mas->cancel_done);
init_completion(&mas->abort_done);
+ init_completion(&mas->xfer_done);
+ init_completion(&mas->tx_cb);
+ init_completion(&mas->rx_cb);
spin_lock_init(&mas->lock);
pm_runtime_use_autosuspend(&pdev->dev);
pm_runtime_set_autosuspend_delay(&pdev->dev, 250);
@@ -661,6 +1025,15 @@ static int spi_geni_probe(struct platform_device *pdev)
if (ret)
goto spi_geni_probe_runtime_disable;

+ /*
+ * query 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
+ */
+ mas->cur_xfer_mode = get_xfer_mode(spi);
+ 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;
--
2.26.2