Messages in this thread | | | Date | Tue, 23 Apr 2024 16:08:04 +0200 | From | neil.armstrong@linaro ... | Subject | Re: [PATCH] serial: msm: Unify TX and RX DMA paths |
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Hi Marek,
On 23/04/2024 14:08, Marek Szyprowski wrote: > Use scatterlist-based API also for RX mode to unify TX and RX DMA paths > as well as simplify the whole driver code a bit.
Thanks for the patch, I have no idea if this is right or wrong.
Greg, I think we should wait until this change is fully tested on multiple platforms including DMA usage (bluetooth) before aplying it.
Thanks, Neil
> > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> > --- > drivers/tty/serial/msm_serial.c | 86 +++++++++++++-------------------- > 1 file changed, 34 insertions(+), 52 deletions(-) > > diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c > index 0a9c5219df88..d5e00e613f73 100644 > --- a/drivers/tty/serial/msm_serial.c > +++ b/drivers/tty/serial/msm_serial.c > @@ -161,14 +161,8 @@ enum { > struct msm_dma { > struct dma_chan *chan; > enum dma_data_direction dir; > - union { > - struct { > - dma_addr_t phys; > - unsigned char *virt; > - unsigned int count; > - } rx; > - struct scatterlist tx_sg; > - }; > + unsigned char *virt; > + struct scatterlist sg; > dma_cookie_t cookie; > u32 enable_bit; > struct dma_async_tx_descriptor *desc; > @@ -254,13 +248,7 @@ static void msm_stop_dma(struct uart_port *port, struct msm_dma *dma) > unsigned int mapped; > u32 val; > > - if (dma->dir == DMA_TO_DEVICE) { > - mapped = sg_dma_len(&dma->tx_sg); > - } else { > - mapped = dma->rx.count; > - dma->rx.count = 0; > - } > - > + mapped = sg_dma_len(&dma->sg); > dmaengine_terminate_all(dma->chan); > > /* > @@ -275,11 +263,8 @@ static void msm_stop_dma(struct uart_port *port, struct msm_dma *dma) > msm_write(port, val, UARTDM_DMEN); > > if (mapped) { > - if (dma->dir == DMA_TO_DEVICE) { > - dma_unmap_sg(dev, &dma->tx_sg, 1, dma->dir); > - sg_init_table(&dma->tx_sg, 1); > - } else > - dma_unmap_single(dev, dma->rx.phys, mapped, dma->dir); > + dma_unmap_sg(dev, &dma->sg, 1, dma->dir); > + sg_init_table(&dma->sg, 1); > } > } > > @@ -299,7 +284,7 @@ static void msm_release_dma(struct msm_port *msm_port) > if (dma->chan) { > msm_stop_dma(&msm_port->uart, dma); > dma_release_channel(dma->chan); > - kfree(dma->rx.virt); > + kfree(dma->virt); > } > > memset(dma, 0, sizeof(*dma)); > @@ -371,8 +356,8 @@ static void msm_request_rx_dma(struct msm_port *msm_port, resource_size_t base) > > of_property_read_u32(dev->of_node, "qcom,rx-crci", &crci); > > - dma->rx.virt = kzalloc(UARTDM_RX_SIZE, GFP_KERNEL); > - if (!dma->rx.virt) > + dma->virt = kzalloc(UARTDM_RX_SIZE, GFP_KERNEL); > + if (!dma->virt) > goto rel_rx; > > memset(&conf, 0, sizeof(conf)); > @@ -399,7 +384,7 @@ static void msm_request_rx_dma(struct msm_port *msm_port, resource_size_t base) > > return; > err: > - kfree(dma->rx.virt); > + kfree(dma->virt); > rel_rx: > dma_release_channel(dma->chan); > no_rx: > @@ -434,7 +419,7 @@ static void msm_start_tx(struct uart_port *port) > struct msm_dma *dma = &msm_port->tx_dma; > > /* Already started in DMA mode */ > - if (sg_dma_len(&dma->tx_sg)) > + if (sg_dma_len(&dma->sg)) > return; > > msm_port->imr |= MSM_UART_IMR_TXLEV; > @@ -462,12 +447,12 @@ static void msm_complete_tx_dma(void *args) > uart_port_lock_irqsave(port, &flags); > > /* Already stopped */ > - if (!sg_dma_len(&dma->tx_sg)) > + if (!sg_dma_len(&dma->sg)) > goto done; > > dmaengine_tx_status(dma->chan, dma->cookie, &state); > > - dma_unmap_sg(port->dev, &dma->tx_sg, 1, dma->dir); > + dma_unmap_sg(port->dev, &dma->sg, 1, dma->dir); > > val = msm_read(port, UARTDM_DMEN); > val &= ~dma->enable_bit; > @@ -478,9 +463,9 @@ static void msm_complete_tx_dma(void *args) > msm_write(port, MSM_UART_CR_TX_ENABLE, MSM_UART_CR); > } > > - count = sg_dma_len(&dma->tx_sg) - state.residue; > + count = sg_dma_len(&dma->sg) - state.residue; > uart_xmit_advance(port, count); > - sg_init_table(&dma->tx_sg, 1); > + sg_init_table(&dma->sg, 1); > > /* Restore "Tx FIFO below watermark" interrupt */ > msm_port->imr |= MSM_UART_IMR_TXLEV; > @@ -503,16 +488,16 @@ static int msm_handle_tx_dma(struct msm_port *msm_port, unsigned int count) > int ret; > u32 val; > > - sg_init_table(&dma->tx_sg, 1); > - kfifo_dma_out_prepare(&tport->xmit_fifo, &dma->tx_sg, 1, count); > + sg_init_table(&dma->sg, 1); > + kfifo_dma_out_prepare(&tport->xmit_fifo, &dma->sg, 1, count); > > - mapped = dma_map_sg(port->dev, &dma->tx_sg, 1, dma->dir); > + mapped = dma_map_sg(port->dev, &dma->sg, 1, dma->dir); > if (!mapped) { > ret = -EIO; > goto zero_sg; > } > > - dma->desc = dmaengine_prep_slave_sg(dma->chan, &dma->tx_sg, 1, > + dma->desc = dmaengine_prep_slave_sg(dma->chan, &dma->sg, 1, > DMA_MEM_TO_DEV, > DMA_PREP_INTERRUPT | > DMA_PREP_FENCE); > @@ -550,9 +535,9 @@ static int msm_handle_tx_dma(struct msm_port *msm_port, unsigned int count) > dma_async_issue_pending(dma->chan); > return 0; > unmap: > - dma_unmap_sg(port->dev, &dma->tx_sg, 1, dma->dir); > + dma_unmap_sg(port->dev, &dma->sg, 1, dma->dir); > zero_sg: > - sg_init_table(&dma->tx_sg, 1); > + sg_init_table(&dma->sg, 1); > return ret; > } > > @@ -569,7 +554,7 @@ static void msm_complete_rx_dma(void *args) > uart_port_lock_irqsave(port, &flags); > > /* Already stopped */ > - if (!dma->rx.count) > + if (!sg_dma_len(&dma->sg)) > goto done; > > val = msm_read(port, UARTDM_DMEN); > @@ -586,14 +571,13 @@ static void msm_complete_rx_dma(void *args) > > port->icount.rx += count; > > - dma->rx.count = 0; > - > - dma_unmap_single(port->dev, dma->rx.phys, UARTDM_RX_SIZE, dma->dir); > + dma_unmap_sg(port->dev, &dma->sg, 1, dma->dir); > + sg_init_table(&dma->sg, 1); > > for (i = 0; i < count; i++) { > char flag = TTY_NORMAL; > > - if (msm_port->break_detected && dma->rx.virt[i] == 0) { > + if (msm_port->break_detected && dma->virt[i] == 0) { > port->icount.brk++; > flag = TTY_BREAK; > msm_port->break_detected = false; > @@ -604,9 +588,9 @@ static void msm_complete_rx_dma(void *args) > if (!(port->read_status_mask & MSM_UART_SR_RX_BREAK)) > flag = TTY_NORMAL; > > - sysrq = uart_prepare_sysrq_char(port, dma->rx.virt[i]); > + sysrq = uart_prepare_sysrq_char(port, dma->virt[i]); > if (!sysrq) > - tty_insert_flip_char(tport, dma->rx.virt[i], flag); > + tty_insert_flip_char(tport, dma->virt[i], flag); > } > > msm_start_rx_dma(msm_port); > @@ -630,14 +614,13 @@ static void msm_start_rx_dma(struct msm_port *msm_port) > if (!dma->chan) > return; > > - dma->rx.phys = dma_map_single(uart->dev, dma->rx.virt, > - UARTDM_RX_SIZE, dma->dir); > - ret = dma_mapping_error(uart->dev, dma->rx.phys); > - if (ret) > + sg_init_one(&dma->sg, dma->virt, UARTDM_RX_SIZE); > + ret = dma_map_sg(uart->dev, &dma->sg, 1, dma->dir); > + if (!ret) > goto sw_mode; > > - dma->desc = dmaengine_prep_slave_single(dma->chan, dma->rx.phys, > - UARTDM_RX_SIZE, DMA_DEV_TO_MEM, > + dma->desc = dmaengine_prep_slave_sg(dma->chan, &dma->sg, 1, > + DMA_DEV_TO_MEM, > DMA_PREP_INTERRUPT); > if (!dma->desc) > goto unmap; > @@ -664,8 +647,6 @@ static void msm_start_rx_dma(struct msm_port *msm_port) > > msm_write(uart, msm_port->imr, MSM_UART_IMR); > > - dma->rx.count = UARTDM_RX_SIZE; > - > dma_async_issue_pending(dma->chan); > > msm_write(uart, MSM_UART_CR_CMD_RESET_STALE_INT, MSM_UART_CR); > @@ -684,7 +665,8 @@ static void msm_start_rx_dma(struct msm_port *msm_port) > > return; > unmap: > - dma_unmap_single(uart->dev, dma->rx.phys, UARTDM_RX_SIZE, dma->dir); > + dma_unmap_sg(uart->dev, &dma->sg, 1, dma->dir); > + sg_init_table(&dma->sg, 1); > > sw_mode: > /* > @@ -967,7 +949,7 @@ static irqreturn_t msm_uart_irq(int irq, void *dev_id) > } > > if (misr & (MSM_UART_IMR_RXLEV | MSM_UART_IMR_RXSTALE)) { > - if (dma->rx.count) { > + if (sg_dma_len(&dma->sg)) { > val = MSM_UART_CR_CMD_STALE_EVENT_DISABLE; > msm_write(port, val, MSM_UART_CR); > val = MSM_UART_CR_CMD_RESET_STALE_INT;
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