Messages in this thread | | | Date | Fri, 25 Nov 2022 10:59:25 +0000 | Subject | Re: [V2] spi: spi-geni-qcom: Add support for SE DMA mode | From | Srinivas Kandagatla <> |
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Thanks for your patch Vijaya,
On 21/11/2022 14:19, Vijaya Krishna Nivarthi wrote: > SE DMA mode can be used for larger transfers and FIFO mode > for smaller transfers.
Over all the patch looks good, but with few minor nits around coding conventions. > > Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com> > --- > drivers/spi/spi-geni-qcom.c | 211 ++++++++++++++++++++++++++++++++++---------- > 1 file changed, 165 insertions(+), 46 deletions(-) > > diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c > index 4e83cc5..102529a 100644 > --- a/drivers/spi/spi-geni-qcom.c > +++ b/drivers/spi/spi-geni-qcom.c > @@ -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 +97,7 @@ struct spi_geni_master { > struct dma_chan *tx; > struct dma_chan *rx; > int cur_xfer_mode; > + u32 cur_m_cmd; > }; > > static int get_spi_clk_cfg(unsigned int speed_hz, > @@ -129,23 +132,26 @@ 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) indentation looks off.
> { > 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);
empty line here would make the code more readable.
> + 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 +168,45 @@ 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 (mas->cur_m_cmd & SPI_TX_ONLY) { > + 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"); > + } > + if (mas->cur_m_cmd & SPI_RX_ONLY) { > + 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"); > + } > + > + if (xfer) { > + if (xfer->tx_buf && xfer->tx_dma) > + geni_se_tx_dma_unprep(se, xfer->tx_dma, xfer->len); > + if (xfer->rx_buf && xfer->rx_dma) > + geni_se_rx_dma_unprep(se, xfer->rx_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. > + * isr will set cur_xfer to NULL when done. > + * Unnecessary error but cannot be helped. > + * Only do reset, dma_unprep is already done by isr. > + */ > + dev_err(mas->dev, "Cancel/Abort on completed SPI transfer\n"); > + } > + } > } > > static void handle_gpi_timeout(struct spi_master *spi, struct spi_message *msg) > @@ -178,7 +223,8 @@ 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); > @@ -260,7 +306,7 @@ 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 +528,12 @@ 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 +544,7 @@ 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 +648,7 @@ 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 +767,12 @@ 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)
consider adjusting the tabs once you change the function name. > { > u32 m_cmd = 0; > - u32 len; > + u32 len, fifo_size; > struct geni_se *se = &mas->se; > int ret; > > @@ -748,7 +799,7 @@ 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;xxxxxxx > @@ -771,6 +822,13 @@ static void setup_fifo_xfer(struct spi_transfer *xfer, > writel(len, se->base + SE_SPI_RX_TRANS_LEN); > mas->rx_rem_bytes = xfer->len; > } > + mas->cur_m_cmd = m_cmd; > + > + /* Select transfer mode based on transfer length */ > + fifo_size = > + mas->tx_fifo_depth * mas->fifo_width_bits / mas->cur_bits_per_word;
line can go up to 100 chars
> + mas->cur_xfer_mode = (len <= fifo_size) ? GENI_SE_FIFO : GENI_SE_DMA;
I do not see any protection for cur_xfer_mode? Isn't it true that it could be modified here while an interrupt handler is using this?
> + geni_se_select_mode(se, mas->cur_xfer_mode); > > /* > * Lock around right before we start the transfer since our > @@ -778,11 +836,39 @@ static void setup_fifo_xfer(struct spi_transfer *xfer, > */ > 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, &xfer->rx_dma); > + if (ret) { > + dev_err(mas->dev, "Failed to setup Rx dma %d\n", ret); > + xfer->rx_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, &xfer->tx_dma); > + if (ret) { > + dev_err(mas->dev, "Failed to setup Tx dma %d\n", ret); > + xfer->tx_dma = 0; > + if (m_cmd & SPI_RX_ONLY && xfer->rx_dma) { > + /* Unmap rx buffer if duplex transfer */ > + geni_se_rx_dma_unprep(se, xfer->rx_dma, xfer->len); > + xfer->rx_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 +876,7 @@ 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 +885,12 @@ 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 +913,66 @@ 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) {
Switch case?
...
> + } > + } else if (mas->cur_xfer_mode == GENI_SE_DMA) { > + const struct spi_transfer *xfer = mas->cur_xfer;
--srini
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