Re: [PATCH v5] i2c: qcom-geni: Add support for GPI DMA

Dmitry Baryshkov
2022-02-17T17:51:39Z

On Mon, 31 Jan 2022 at 15:04, Vinod Koul <vkoul@kernel.org> wrote:
>
> QUP Serial engines supports data transfers thru FIFO mode, SE DMA mode and
> lastly GPI DMA mode. Former two are already supported and this adds supports the
> last mode.
>
> In GPI DMA mode, the firmware is issued commands by driver to perform DMA
> and setup the serial port.
>
> Signed-off-by: Vinod Koul <vkoul@kernel.org>
> ---
>
> Changes since v4:
> - Fix buildbot warn
> - Fix flase warn reported by Alexey
> - Fix feedback from Bjorn and cleanup the probe code and add more details
> in changelog
>
> Changes since v3:
> - remove separate tx and rx function for gsi dma and make a common one
> - remove global structs and use local variables instead
>
> drivers/i2c/busses/i2c-qcom-geni.c | 300 ++++++++++++++++++++++++++---
> 1 file changed, 273 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
> index 6d635a7c104c..696253d178a6 100644
> --- a/drivers/i2c/busses/i2c-qcom-geni.c
> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
> @@ -3,7 +3,9 @@
>
> #include <linux/acpi.h>
> #include <linux/clk.h>
> +#include <linux/dmaengine.h>
> #include <linux/dma-mapping.h>
> +#include <linux/dma/qcom-gpi-dma.h>
> #include <linux/err.h>
> #include <linux/i2c.h>
> #include <linux/interrupt.h>
> @@ -48,6 +50,9 @@
> #define LOW_COUNTER_SHFT 10
> #define CYCLE_COUNTER_MSK GENMASK(9, 0)
>
> +#define I2C_PACK_TX BIT(0)
> +#define I2C_PACK_RX BIT(1)
> +
> enum geni_i2c_err_code {
> GP_IRQ0,
> NACK,
> @@ -89,6 +94,9 @@ struct geni_i2c_dev {
> void *dma_buf;
> size_t xfer_len;
> dma_addr_t dma_addr;
> + struct dma_chan *tx_c;
> + struct dma_chan *rx_c;
> + bool gpi_mode;
> };
>
> struct geni_i2c_err_log {
> @@ -456,12 +464,199 @@ static int geni_i2c_tx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
> return gi2c->err;
> }
>
> +static void i2c_gpi_cb_result(void *cb, const struct dmaengine_result *result)
> +{
> + struct geni_i2c_dev *gi2c = cb;
> +
> + if (result->result != DMA_TRANS_NOERROR) {
> + dev_err(gi2c->se.dev, "DMA txn failed:%d\n", result->result);
> + return;
> + }
> +
> + if (result->residue)
> + dev_dbg(gi2c->se.dev, "DMA xfer has pending: %d\n", result->residue);
> +
> + complete(&gi2c->done);
> +}
> +
> +static void geni_i2c_gpi_unmap(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
> + void *tx_buf, dma_addr_t tx_addr,
> + void *rx_buf, dma_addr_t rx_addr)
> +{
> + if (tx_buf) {
> + dma_unmap_single(gi2c->se.dev->parent, tx_addr, msg->len, DMA_TO_DEVICE);
> + i2c_put_dma_safe_msg_buf(tx_buf, msg, false);
> + }
> +
> + if (rx_buf) {
> + dma_unmap_single(gi2c->se.dev->parent, rx_addr, msg->len, DMA_FROM_DEVICE);
> + i2c_put_dma_safe_msg_buf(rx_buf, msg, false);
> + }
> +}
> +
> +static int geni_i2c_gpi(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
> + struct dma_slave_config *config, dma_addr_t *dma_addr_p,
> + void **buf, unsigned int op, struct dma_chan *dma_chan)
> +{
> + struct gpi_i2c_config *peripheral;
> + unsigned int flags;
> + void *dma_buf;
> + dma_addr_t addr;
> + enum dma_data_direction map_dirn;
> + enum dma_transfer_direction dma_dirn;
> + struct dma_async_tx_descriptor *desc;
> + int ret;
> +
> + peripheral = config->peripheral_config;
> +
> + dma_buf = i2c_get_dma_safe_msg_buf(msg, 1);
> + if (!dma_buf)
> + return -ENOMEM;
> +
> + if (op == I2C_WRITE)
> + map_dirn = DMA_TO_DEVICE;
> + else
> + map_dirn = DMA_FROM_DEVICE;
> +
> + addr = dma_map_single(gi2c->se.dev->parent, dma_buf, msg->len, map_dirn);
> + if (dma_mapping_error(gi2c->se.dev->parent, addr)) {
> + i2c_put_dma_safe_msg_buf(dma_buf, msg, false);
> + return -ENOMEM;
> + }
> +
> + /* set the length as message for rx txn */
> + peripheral->rx_len = msg->len;
> + peripheral->op = op;
> +
> + ret = dmaengine_slave_config(dma_chan, config);
> + if (ret) {
> + dev_err(gi2c->se.dev, "dma config error: %d for op:%d\n", ret, op);
> + goto err_config;
> + }
> +
> + peripheral->set_config = 0;
> + peripheral->multi_msg = true;
> + flags = DMA_PREP_INTERRUPT | DMA_CTRL_ACK;
> +
> + if (op == I2C_WRITE)
> + dma_dirn = DMA_MEM_TO_DEV;
> + else
> + dma_dirn = DMA_DEV_TO_MEM;
> +
> + desc = dmaengine_prep_slave_single(dma_chan, addr, msg->len, dma_dirn, flags);
> + if (!desc) {
> + dev_err(gi2c->se.dev, "prep_slave_sg failed\n");
> + ret = -EIO;
> + goto err_config;
> + }
> +
> + desc->callback_result = i2c_gpi_cb_result;
> + desc->callback_param = gi2c;
> +
> + dmaengine_submit(desc);
> + *dma_addr_p = addr;
> +
> + return 0;
> +
> +err_config:
> + dma_unmap_single(gi2c->se.dev->parent, addr, msg->len, map_dirn);
> + i2c_put_dma_safe_msg_buf(dma_buf, msg, false);
> + return ret;
> +}
> +
> +static int geni_i2c_gpi_xfer(struct geni_i2c_dev *gi2c, struct i2c_msg msgs[], int num)
> +{
> + struct dma_slave_config config = {};
> + struct gpi_i2c_config peripheral = {};
> + int i, ret = 0, timeout;
> + dma_addr_t tx_addr, rx_addr;
> + void *tx_buf = NULL, *rx_buf = NULL;
> + const struct geni_i2c_clk_fld *itr = gi2c->clk_fld;
> +
> + config.peripheral_config = &peripheral;
> + config.peripheral_size = sizeof(peripheral);
> +
> + peripheral.pack_enable = I2C_PACK_TX | I2C_PACK_RX;
> + peripheral.cycle_count = itr->t_cycle_cnt;
> + peripheral.high_count = itr->t_high_cnt;
> + peripheral.low_count = itr->t_low_cnt;
> + peripheral.clk_div = itr->clk_div;
> + peripheral.set_config = 1;
> + peripheral.multi_msg = false;
> +
> + for (i = 0; i < num; i++) {
> + gi2c->cur = &msgs[i];
> + dev_dbg(gi2c->se.dev, "msg[%d].len:%d\n", i, gi2c->cur->len);
> +
> + peripheral.stretch = 0;
> + if (i < num - 1)
> + peripheral.stretch = 1;
> +
> + peripheral.addr = msgs[i].addr;
> +
> + if (msgs[i].flags & I2C_M_RD) {
> + ret = geni_i2c_gpi(gi2c, &msgs[i], &config, &rx_addr, &rx_buf, I2C_READ, gi2c->rx_c);
> + if (ret)
> + goto err;
> + }
> +
> + ret = geni_i2c_gpi(gi2c, &msgs[i], &config, &tx_addr, &tx_buf, I2C_WRITE, gi2c->tx_c);
> + if (ret)
> + goto err;
> +
> + if (msgs[i].flags & I2C_M_RD)
> + dma_async_issue_pending(gi2c->rx_c);
> + dma_async_issue_pending(gi2c->tx_c);
> +
> + timeout = wait_for_completion_timeout(&gi2c->done, XFER_TIMEOUT);
> + if (!timeout) {
> + dev_err(gi2c->se.dev, "I2C timeout gpi flags:%d addr:0x%x\n",
> + gi2c->cur->flags, gi2c->cur->addr);
> + ret = gi2c->err = -ETIMEDOUT;
> + goto err;
> + }
> +
> + geni_i2c_gpi_unmap(gi2c, &msgs[i], tx_buf, tx_addr, rx_buf, rx_addr);
> + }
> +
> + return 0;
> +
> +err:
> + dmaengine_terminate_sync(gi2c->rx_c);
> + dmaengine_terminate_sync(gi2c->tx_c);
> + geni_i2c_gpi_unmap(gi2c, &msgs[i], tx_buf, tx_addr, rx_buf, rx_addr);
> + return ret;
> +}
> +
> +static int geni_i2c_fifo_xfer(struct geni_i2c_dev *gi2c,
> + struct i2c_msg msgs[], int num)
> +{
> + int i, ret = 0;
> +
> + for (i = 0; i < num; i++) {
> + u32 m_param = i < (num - 1) ? STOP_STRETCH : 0;
> +
> + m_param |= ((msgs[i].addr << SLV_ADDR_SHFT) & SLV_ADDR_MSK);
> +
> + gi2c->cur = &msgs[i];
> + if (msgs[i].flags & I2C_M_RD)
> + ret = geni_i2c_rx_one_msg(gi2c, &msgs[i], m_param);
> + else
> + ret = geni_i2c_tx_one_msg(gi2c, &msgs[i], m_param);
> +
> + if (ret)
> + break;

I'd suggest to 'return ret' here and change the return line to 'return num'.

> + }
> +
> + return ret;
> +}
> +
> static int geni_i2c_xfer(struct i2c_adapter *adap,
> struct i2c_msg msgs[],
> int num)
> {
> struct geni_i2c_dev *gi2c = i2c_get_adapdata(adap);
> - int i, ret;
> + int ret;
>
> gi2c->err = 0;
> reinit_completion(&gi2c->done);
> @@ -475,22 +670,11 @@ static int geni_i2c_xfer(struct i2c_adapter *adap,
> }
>
> qcom_geni_i2c_conf(gi2c);
> - for (i = 0; i < num; i++) {
> - u32 m_param = i < (num - 1) ? STOP_STRETCH : 0;
> -
> - m_param |= ((msgs[i].addr << SLV_ADDR_SHFT) & SLV_ADDR_MSK);
> -
> - gi2c->cur = &msgs[i];
> - if (msgs[i].flags & I2C_M_RD)
> - ret = geni_i2c_rx_one_msg(gi2c, &msgs[i], m_param);
> - else
> - ret = geni_i2c_tx_one_msg(gi2c, &msgs[i], m_param);
>
> - if (ret)
> - break;
> - }
> - if (ret == 0)
> - ret = num;
> + if (gi2c->gpi_mode)
> + ret = geni_i2c_gpi_xfer(gi2c, msgs, num);
> + else
> + ret = geni_i2c_fifo_xfer(gi2c, msgs, num);

We should return num if ret is 0 here (or in
geni_i2c_fifo_xfer()/geni_i2c_gpi_xfer()).

>
> pm_runtime_mark_last_busy(gi2c->se.dev);
> pm_runtime_put_autosuspend(gi2c->se.dev);
> @@ -517,11 +701,52 @@ static const struct acpi_device_id geni_i2c_acpi_match[] = {
> MODULE_DEVICE_TABLE(acpi, geni_i2c_acpi_match);
> #endif
>
> +static void release_gpi_dma(struct geni_i2c_dev *gi2c)
> +{
> + if (gi2c->rx_c)
> + dma_release_channel(gi2c->rx_c);
> +
> + if (gi2c->tx_c)
> + dma_release_channel(gi2c->tx_c);
> +}
> +
> +static int setup_gpi_dma(struct geni_i2c_dev *gi2c)
> +{
> + int ret;
> +
> + geni_se_select_mode(&gi2c->se, GENI_GPI_DMA);
> + gi2c->tx_c = dma_request_chan(gi2c->se.dev, "tx");
> + if (IS_ERR(gi2c->tx_c)) {
> + ret = dev_err_probe(gi2c->se.dev, PTR_ERR(gi2c->tx_c),
> + "Failed to get tx DMA ch\n");
> + if (ret < 0)
> + goto err_tx;
> + }
> +
> + gi2c->rx_c = dma_request_chan(gi2c->se.dev, "rx");
> + if (IS_ERR(gi2c->rx_c)) {
> + ret = dev_err_probe(gi2c->se.dev, PTR_ERR(gi2c->rx_c),
> + "Failed to get rx DMA ch\n");
> + if (ret < 0)
> + goto err_rx;
> + }
> +
> + dev_dbg(gi2c->se.dev, "Grabbed GPI dma channels\n");
> + return 0;
> +
> +err_rx:
> + dma_release_channel(gi2c->tx_c);
> + gi2c->tx_c = NULL;
> +err_tx:
> + gi2c->rx_c = NULL;
> + return ret;
> +}
> +
> static int geni_i2c_probe(struct platform_device *pdev)
> {
> struct geni_i2c_dev *gi2c;
> struct resource *res;
> - u32 proto, tx_depth;
> + u32 proto, tx_depth, fifo_disable;
> int ret;
> struct device *dev = &pdev->dev;
>
> @@ -601,27 +826,43 @@ static int geni_i2c_probe(struct platform_device *pdev)
> return ret;
> }
> proto = geni_se_read_proto(&gi2c->se);
> - tx_depth = geni_se_get_tx_fifo_depth(&gi2c->se);
> if (proto != GENI_SE_I2C) {
> dev_err(dev, "Invalid proto %d\n", proto);
> geni_se_resources_off(&gi2c->se);
> return -ENXIO;
> }
> - gi2c->tx_wm = tx_depth - 1;
> - geni_se_init(&gi2c->se, gi2c->tx_wm, tx_depth);
> - geni_se_config_packing(&gi2c->se, BITS_PER_BYTE, PACKING_BYTES_PW,
> - true, true, true);
> +
> + fifo_disable = readl_relaxed(gi2c->se.base + GENI_IF_DISABLE_RO) & FIFO_IF_DISABLE;
> + if (fifo_disable) {
> + /* FIFO is disabled, so we can only use GPI DMA */
> + gi2c->gpi_mode = true;
> + ret = setup_gpi_dma(gi2c);
> + if (ret) {
> + dev_err(dev, "Failed to setup GPI DMA mode:%d ret\n", ret);
> + return ret;
> + }
> +
> + dev_dbg(dev, "Using GPI DMA mode for I2C\n");
> + } else {
> + gi2c->gpi_mode = false;
> + tx_depth = geni_se_get_tx_fifo_depth(&gi2c->se);
> + gi2c->tx_wm = tx_depth - 1;
> + geni_se_init(&gi2c->se, gi2c->tx_wm, tx_depth);
> + geni_se_config_packing(&gi2c->se, BITS_PER_BYTE,
> + PACKING_BYTES_PW, true, true, true);
> +
> + dev_dbg(dev, "i2c fifo/se-dma mode. fifo depth:%d\n", tx_depth);
> + }
> +
> ret = geni_se_resources_off(&gi2c->se);
> if (ret) {
> dev_err(dev, "Error turning off resources %d\n", ret);
> - return ret;
> + goto err_dma;
> }
>
> ret = geni_icc_disable(&gi2c->se);
> if (ret)
> - return ret;
> -
> - dev_dbg(dev, "i2c fifo/se-dma mode. fifo depth:%d\n", tx_depth);
> + goto err_dma;
>
> gi2c->suspended = 1;
> pm_runtime_set_suspended(gi2c->se.dev);
> @@ -633,18 +874,23 @@ static int geni_i2c_probe(struct platform_device *pdev)
> if (ret) {
> dev_err(dev, "Error adding i2c adapter %d\n", ret);
> pm_runtime_disable(gi2c->se.dev);
> - return ret;
> + goto err_dma;
> }
>
> dev_dbg(dev, "Geni-I2C adaptor successfully added\n");
>
> return 0;
> +
> +err_dma:
> + release_gpi_dma(gi2c);
> + return ret;
> }
>
> static int geni_i2c_remove(struct platform_device *pdev)
> {
> struct geni_i2c_dev *gi2c = platform_get_drvdata(pdev);
>
> + release_gpi_dma(gi2c);
> i2c_del_adapter(&gi2c->adap);
> pm_runtime_disable(gi2c->se.dev);
> return 0;
> --
> 2.31.1
>

--
With best wishes
Dmitry