spi: spi-geni-qcom: Add support for SE DMA mode
authorVijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
Thu, 8 Dec 2022 14:25:44 +0000 (19:55 +0530)
committerMark Brown <broonie@kernel.org>
Sun, 25 Dec 2022 23:34:34 +0000 (23:34 +0000)
SE DMA mode can be used for larger transfers and FIFO mode
for smaller transfers.

Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/1670509544-15977-1-git-send-email-quic_vnivarth@quicinc.com
Signed-off-by: Mark Brown <broonie@kernel.org>
drivers/spi/spi-geni-qcom.c

index 4e83cc5..e1b2e0b 100644 (file)
@@ -87,6 +87,8 @@ struct spi_geni_master {
        struct completion cs_done;
        struct completion cancel_done;
        struct completion abort_done;
+       struct completion tx_reset_done;
+       struct completion rx_reset_done;
        unsigned int oversampling;
        spinlock_t lock;
        int irq;
@@ -95,6 +97,8 @@ struct spi_geni_master {
        struct dma_chan *tx;
        struct dma_chan *rx;
        int cur_xfer_mode;
+       dma_addr_t tx_se_dma;
+       dma_addr_t rx_se_dma;
 };
 
 static int get_spi_clk_cfg(unsigned int speed_hz,
@@ -129,23 +133,27 @@ static int get_spi_clk_cfg(unsigned int speed_hz,
        return ret;
 }
 
-static void handle_fifo_timeout(struct spi_master *spi,
+static void handle_se_timeout(struct spi_master *spi,
                                struct spi_message *msg)
 {
        struct spi_geni_master *mas = spi_master_get_devdata(spi);
        unsigned long time_left;
        struct geni_se *se = &mas->se;
+       const struct spi_transfer *xfer;
 
        spin_lock_irq(&mas->lock);
        reinit_completion(&mas->cancel_done);
-       writel(0, se->base + SE_GENI_TX_WATERMARK_REG);
+       if (mas->cur_xfer_mode == GENI_SE_FIFO)
+               writel(0, se->base + SE_GENI_TX_WATERMARK_REG);
+
+       xfer = mas->cur_xfer;
        mas->cur_xfer = NULL;
        geni_se_cancel_m_cmd(se);
        spin_unlock_irq(&mas->lock);
 
        time_left = wait_for_completion_timeout(&mas->cancel_done, HZ);
        if (time_left)
-               return;
+               goto unmap_if_dma;
 
        spin_lock_irq(&mas->lock);
        reinit_completion(&mas->abort_done);
@@ -162,6 +170,39 @@ static void handle_fifo_timeout(struct spi_master *spi,
                 */
                mas->abort_failed = true;
        }
+
+unmap_if_dma:
+       if (mas->cur_xfer_mode == GENI_SE_DMA) {
+               if (xfer) {
+                       if (xfer->tx_buf && mas->tx_se_dma) {
+                               spin_lock_irq(&mas->lock);
+                               reinit_completion(&mas->tx_reset_done);
+                               writel(1, se->base + SE_DMA_TX_FSM_RST);
+                               spin_unlock_irq(&mas->lock);
+                               time_left = wait_for_completion_timeout(&mas->tx_reset_done, HZ);
+                               if (!time_left)
+                                       dev_err(mas->dev, "DMA TX RESET failed\n");
+                               geni_se_tx_dma_unprep(se, mas->tx_se_dma, xfer->len);
+                       }
+                       if (xfer->rx_buf && mas->rx_se_dma) {
+                               spin_lock_irq(&mas->lock);
+                               reinit_completion(&mas->rx_reset_done);
+                               writel(1, se->base + SE_DMA_RX_FSM_RST);
+                               spin_unlock_irq(&mas->lock);
+                               time_left = wait_for_completion_timeout(&mas->rx_reset_done, HZ);
+                               if (!time_left)
+                                       dev_err(mas->dev, "DMA RX RESET failed\n");
+                               geni_se_rx_dma_unprep(se, mas->rx_se_dma, xfer->len);
+                       }
+               } else {
+                       /*
+                        * This can happen if a timeout happened and we had to wait
+                        * for lock in this function because isr was holding the lock
+                        * and handling transfer completion at that time.
+                        */
+                       dev_warn(mas->dev, "Cancel/Abort on completed SPI transfer\n");
+               }
+       }
 }
 
 static void handle_gpi_timeout(struct spi_master *spi, struct spi_message *msg)
@@ -178,7 +219,8 @@ static void spi_geni_handle_err(struct spi_master *spi, struct spi_message *msg)
 
        switch (mas->cur_xfer_mode) {
        case GENI_SE_FIFO:
-               handle_fifo_timeout(spi, msg);
+       case GENI_SE_DMA:
+               handle_se_timeout(spi, msg);
                break;
        case GENI_GPI_DMA:
                handle_gpi_timeout(spi, msg);
@@ -250,6 +292,8 @@ static void spi_geni_set_cs(struct spi_device *slv, bool set_flag)
        }
 
        mas->cs_flag = set_flag;
+       /* set xfer_mode to FIFO to complete cs_done in isr */
+       mas->cur_xfer_mode = GENI_SE_FIFO;
        reinit_completion(&mas->cs_done);
        if (set_flag)
                geni_se_setup_m_cmd(se, SPI_CS_ASSERT, 0);
@@ -260,7 +304,7 @@ static void spi_geni_set_cs(struct spi_device *slv, bool set_flag)
        time_left = wait_for_completion_timeout(&mas->cs_done, HZ);
        if (!time_left) {
                dev_warn(mas->dev, "Timeout setting chip select\n");
-               handle_fifo_timeout(spi, NULL);
+               handle_se_timeout(spi, NULL);
        }
 
 exit:
@@ -482,8 +526,12 @@ static bool geni_can_dma(struct spi_controller *ctlr,
 {
        struct spi_geni_master *mas = spi_master_get_devdata(slv->master);
 
-       /* check if dma is supported */
-       return mas->cur_xfer_mode != GENI_SE_FIFO;
+       /*
+        * Return true if transfer needs to be mapped prior to
+        * calling transfer_one which is the case only for GPI_DMA.
+        * For SE_DMA mode, map/unmap is done in geni_se_*x_dma_prep.
+        */
+       return mas->cur_xfer_mode == GENI_GPI_DMA;
 }
 
 static int spi_geni_prepare_message(struct spi_master *spi,
@@ -494,6 +542,7 @@ static int spi_geni_prepare_message(struct spi_master *spi,
 
        switch (mas->cur_xfer_mode) {
        case GENI_SE_FIFO:
+       case GENI_SE_DMA:
                if (spi_geni_is_abort_still_pending(mas))
                        return -EBUSY;
                ret = setup_fifo_params(spi_msg->spi, spi);
@@ -597,7 +646,7 @@ static int spi_geni_init(struct spi_geni_master *mas)
                        break;
                }
                /*
-                * in case of failure to get dma channel, we can still do the
+                * in case of failure to get gpi 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");
@@ -716,12 +765,12 @@ static void geni_spi_handle_rx(struct spi_geni_master *mas)
        mas->rx_rem_bytes -= rx_bytes;
 }
 
-static void setup_fifo_xfer(struct spi_transfer *xfer,
+static int setup_se_xfer(struct spi_transfer *xfer,
                                struct spi_geni_master *mas,
                                u16 mode, struct spi_master *spi)
 {
        u32 m_cmd = 0;
-       u32 len;
+       u32 len, fifo_size;
        struct geni_se *se = &mas->se;
        int ret;
 
@@ -748,7 +797,7 @@ static void setup_fifo_xfer(struct spi_transfer *xfer,
        /* Speed and bits per word can be overridden per transfer */
        ret = geni_spi_set_clock_and_bw(mas, xfer->speed_hz);
        if (ret)
-               return;
+               return ret;
 
        mas->tx_rem_bytes = 0;
        mas->rx_rem_bytes = 0;
@@ -772,17 +821,50 @@ static void setup_fifo_xfer(struct spi_transfer *xfer,
                mas->rx_rem_bytes = xfer->len;
        }
 
+       /* Select transfer mode based on transfer length */
+       fifo_size = mas->tx_fifo_depth * mas->fifo_width_bits / mas->cur_bits_per_word;
+       mas->cur_xfer_mode = (len <= fifo_size) ? GENI_SE_FIFO : GENI_SE_DMA;
+       geni_se_select_mode(se, mas->cur_xfer_mode);
+
        /*
         * Lock around right before we start the transfer since our
         * interrupt could come in at any time now.
         */
        spin_lock_irq(&mas->lock);
        geni_se_setup_m_cmd(se, m_cmd, FRAGMENTATION);
-       if (m_cmd & SPI_TX_ONLY) {
+
+       if (mas->cur_xfer_mode == GENI_SE_DMA) {
+               if (m_cmd & SPI_RX_ONLY) {
+                       ret =  geni_se_rx_dma_prep(se, xfer->rx_buf,
+                               xfer->len, &mas->rx_se_dma);
+                       if (ret) {
+                               dev_err(mas->dev, "Failed to setup Rx dma %d\n", ret);
+                               mas->rx_se_dma = 0;
+                               goto unlock_and_return;
+                       }
+               }
+               if (m_cmd & SPI_TX_ONLY) {
+                       ret =  geni_se_tx_dma_prep(se, (void *)xfer->tx_buf,
+                               xfer->len, &mas->tx_se_dma);
+                       if (ret) {
+                               dev_err(mas->dev, "Failed to setup Tx dma %d\n", ret);
+                               mas->tx_se_dma = 0;
+                               if (m_cmd & SPI_RX_ONLY) {
+                                       /* Unmap rx buffer if duplex transfer */
+                                       geni_se_rx_dma_unprep(se, mas->rx_se_dma, xfer->len);
+                                       mas->rx_se_dma = 0;
+                               }
+                               goto unlock_and_return;
+                       }
+               }
+       } else if (m_cmd & SPI_TX_ONLY) {
                if (geni_spi_handle_tx(mas))
                        writel(mas->tx_wm, se->base + SE_GENI_TX_WATERMARK_REG);
        }
+
+unlock_and_return:
        spin_unlock_irq(&mas->lock);
+       return ret;
 }
 
 static int spi_geni_transfer_one(struct spi_master *spi,
@@ -790,6 +872,7 @@ static int spi_geni_transfer_one(struct spi_master *spi,
                                struct spi_transfer *xfer)
 {
        struct spi_geni_master *mas = spi_master_get_devdata(spi);
+       int ret;
 
        if (spi_geni_is_abort_still_pending(mas))
                return -EBUSY;
@@ -798,9 +881,12 @@ static int spi_geni_transfer_one(struct spi_master *spi,
        if (!xfer->len)
                return 0;
 
-       if (mas->cur_xfer_mode == GENI_SE_FIFO) {
-               setup_fifo_xfer(xfer, mas, slv->mode, spi);
-               return 1;
+       if (mas->cur_xfer_mode == GENI_SE_FIFO || mas->cur_xfer_mode == GENI_SE_DMA) {
+               ret = setup_se_xfer(xfer, mas, slv->mode, spi);
+               /* SPI framework expects +ve ret code to wait for transfer complete */
+               if (!ret)
+                       ret = 1;
+               return ret;
        }
        return setup_gsi_xfer(xfer, mas, slv, spi);
 }
@@ -823,39 +909,70 @@ static irqreturn_t geni_spi_isr(int irq, void *data)
 
        spin_lock(&mas->lock);
 
-       if ((m_irq & M_RX_FIFO_WATERMARK_EN) || (m_irq & M_RX_FIFO_LAST_EN))
-               geni_spi_handle_rx(mas);
-
-       if (m_irq & M_TX_FIFO_WATERMARK_EN)
-               geni_spi_handle_tx(mas);
-
-       if (m_irq & M_CMD_DONE_EN) {
-               if (mas->cur_xfer) {
+       if (mas->cur_xfer_mode == GENI_SE_FIFO) {
+               if ((m_irq & M_RX_FIFO_WATERMARK_EN) || (m_irq & M_RX_FIFO_LAST_EN))
+                       geni_spi_handle_rx(mas);
+
+               if (m_irq & M_TX_FIFO_WATERMARK_EN)
+                       geni_spi_handle_tx(mas);
+
+               if (m_irq & M_CMD_DONE_EN) {
+                       if (mas->cur_xfer) {
+                               spi_finalize_current_transfer(spi);
+                               mas->cur_xfer = NULL;
+                               /*
+                                * If this happens, then a CMD_DONE came before all the
+                                * Tx buffer bytes were sent out. This is unusual, log
+                                * this condition and disable the WM interrupt to
+                                * prevent the system from stalling due an interrupt
+                                * storm.
+                                *
+                                * If this happens when all Rx bytes haven't been
+                                * received, log the condition. The only known time
+                                * this can happen is if bits_per_word != 8 and some
+                                * registers that expect xfer lengths in num spi_words
+                                * weren't written correctly.
+                                */
+                               if (mas->tx_rem_bytes) {
+                                       writel(0, se->base + SE_GENI_TX_WATERMARK_REG);
+                                       dev_err(mas->dev, "Premature done. tx_rem = %d bpw%d\n",
+                                               mas->tx_rem_bytes, mas->cur_bits_per_word);
+                               }
+                               if (mas->rx_rem_bytes)
+                                       dev_err(mas->dev, "Premature done. rx_rem = %d bpw%d\n",
+                                               mas->rx_rem_bytes, mas->cur_bits_per_word);
+                       } else {
+                               complete(&mas->cs_done);
+                       }
+               }
+       } else if (mas->cur_xfer_mode == GENI_SE_DMA) {
+               const struct spi_transfer *xfer = mas->cur_xfer;
+               u32 dma_tx_status = readl_relaxed(se->base + SE_DMA_TX_IRQ_STAT);
+               u32 dma_rx_status = readl_relaxed(se->base + SE_DMA_RX_IRQ_STAT);
+
+               if (dma_tx_status)
+                       writel(dma_tx_status, se->base + SE_DMA_TX_IRQ_CLR);
+               if (dma_rx_status)
+                       writel(dma_rx_status, se->base + SE_DMA_RX_IRQ_CLR);
+               if (dma_tx_status & TX_DMA_DONE)
+                       mas->tx_rem_bytes = 0;
+               if (dma_rx_status & RX_DMA_DONE)
+                       mas->rx_rem_bytes = 0;
+               if (dma_tx_status & TX_RESET_DONE)
+                       complete(&mas->tx_reset_done);
+               if (dma_rx_status & RX_RESET_DONE)
+                       complete(&mas->rx_reset_done);
+               if (!mas->tx_rem_bytes && !mas->rx_rem_bytes && xfer) {
+                       if (xfer->tx_buf && mas->tx_se_dma) {
+                               geni_se_tx_dma_unprep(se, mas->tx_se_dma, xfer->len);
+                               mas->tx_se_dma = 0;
+                       }
+                       if (xfer->rx_buf && mas->rx_se_dma) {
+                               geni_se_rx_dma_unprep(se, mas->rx_se_dma, xfer->len);
+                               mas->rx_se_dma = 0;
+                       }
                        spi_finalize_current_transfer(spi);
                        mas->cur_xfer = NULL;
-                       /*
-                        * If this happens, then a CMD_DONE came before all the
-                        * Tx buffer bytes were sent out. This is unusual, log
-                        * this condition and disable the WM interrupt to
-                        * prevent the system from stalling due an interrupt
-                        * storm.
-                        *
-                        * If this happens when all Rx bytes haven't been
-                        * received, log the condition. The only known time
-                        * this can happen is if bits_per_word != 8 and some
-                        * registers that expect xfer lengths in num spi_words
-                        * weren't written correctly.
-                        */
-                       if (mas->tx_rem_bytes) {
-                               writel(0, se->base + SE_GENI_TX_WATERMARK_REG);
-                               dev_err(mas->dev, "Premature done. tx_rem = %d bpw%d\n",
-                                       mas->tx_rem_bytes, mas->cur_bits_per_word);
-                       }
-                       if (mas->rx_rem_bytes)
-                               dev_err(mas->dev, "Premature done. rx_rem = %d bpw%d\n",
-                                       mas->rx_rem_bytes, mas->cur_bits_per_word);
-               } else {
-                       complete(&mas->cs_done);
                }
        }
 
@@ -949,6 +1066,8 @@ static int spi_geni_probe(struct platform_device *pdev)
        init_completion(&mas->cs_done);
        init_completion(&mas->cancel_done);
        init_completion(&mas->abort_done);
+       init_completion(&mas->tx_reset_done);
+       init_completion(&mas->rx_reset_done);
        spin_lock_init(&mas->lock);
        pm_runtime_use_autosuspend(&pdev->dev);
        pm_runtime_set_autosuspend_delay(&pdev->dev, 250);