tty: serial: fsl_lpuart: fix DMA mapping

Use the correct device to request the DMA mapping. Otherwise the IOMMU
doesn't get the mapping and it will generate a page fault.

The error messages look like:
[   19.012140] arm-smmu 5000000.iommu: Unhandled context fault: fsr=0x402, iova=0xbbfff800, fsynr=0x3e0021, cbfrsynra=0x828, cb=9
[   19.023593] arm-smmu 5000000.iommu: Unhandled context fault: fsr=0x402, iova=0xbbfff800, fsynr=0x3e0021, cbfrsynra=0x828, cb=9

This was tested on a custom board with a LS1028A SoC.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200306214433.23215-3-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 33798df..f45f97c 100644 (file)
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -409,6 +409,7 @@ static void lpuart_dma_tx(struct lpuart_port *sport)
        struct circ_buf *xmit = &sport->port.state->xmit;
        struct scatterlist *sgl = sport->tx_sgl;
        struct device *dev = sport->port.dev;
+       struct dma_chan *chan = sport->dma_tx_chan;
        int ret;
 
        if (sport->dma_tx_in_progress)
@@ -427,17 +428,19 @@ static void lpuart_dma_tx(struct lpuart_port *sport)
                sg_set_buf(sgl + 1, xmit->buf, xmit->head);
        }
 
-       ret = dma_map_sg(dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
+       ret = dma_map_sg(chan->device->dev, sgl, sport->dma_tx_nents,
+                        DMA_TO_DEVICE);
        if (!ret) {
                dev_err(dev, "DMA mapping error for TX.\n");
                return;
        }
 
-       sport->dma_tx_desc = dmaengine_prep_slave_sg(sport->dma_tx_chan, sgl,
+       sport->dma_tx_desc = dmaengine_prep_slave_sg(chan, sgl,
                                        ret, DMA_MEM_TO_DEV,
                                        DMA_PREP_INTERRUPT);
        if (!sport->dma_tx_desc) {
-               dma_unmap_sg(dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
+               dma_unmap_sg(chan->device->dev, sgl, sport->dma_tx_nents,
+                             DMA_TO_DEVICE);
                dev_err(dev, "Cannot prepare TX slave DMA!\n");
                return;
        }
@@ -446,7 +449,7 @@ static void lpuart_dma_tx(struct lpuart_port *sport)
        sport->dma_tx_desc->callback_param = sport;
        sport->dma_tx_in_progress = true;
        sport->dma_tx_cookie = dmaengine_submit(sport->dma_tx_desc);
-       dma_async_issue_pending(sport->dma_tx_chan);
+       dma_async_issue_pending(chan);
 }
 
 static bool lpuart_stopped_or_empty(struct uart_port *port)
@@ -459,11 +462,13 @@ static void lpuart_dma_tx_complete(void *arg)
        struct lpuart_port *sport = arg;
        struct scatterlist *sgl = &sport->tx_sgl[0];
        struct circ_buf *xmit = &sport->port.state->xmit;
+       struct dma_chan *chan = sport->dma_tx_chan;
        unsigned long flags;
 
        spin_lock_irqsave(&sport->port.lock, flags);
 
-       dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
+       dma_unmap_sg(chan->device->dev, sgl, sport->dma_tx_nents,
+                    DMA_TO_DEVICE);
 
        xmit->tail = (xmit->tail + sport->dma_tx_bytes) & (UART_XMIT_SIZE - 1);
 
@@ -529,15 +534,16 @@ static bool lpuart_is_32(struct lpuart_port *sport)
 static void lpuart_flush_buffer(struct uart_port *port)
 {
        struct lpuart_port *sport = container_of(port, struct lpuart_port, port);
+       struct dma_chan *chan = sport->dma_tx_chan;
        u32 val;
 
        if (sport->lpuart_dma_tx_use) {
                if (sport->dma_tx_in_progress) {
-                       dma_unmap_sg(sport->port.dev, &sport->tx_sgl[0],
+                       dma_unmap_sg(chan->device->dev, &sport->tx_sgl[0],
                                sport->dma_tx_nents, DMA_TO_DEVICE);
                        sport->dma_tx_in_progress = false;
                }
-               dmaengine_terminate_all(sport->dma_tx_chan);
+               dmaengine_terminate_all(chan);
        }
 
        if (lpuart_is_32(sport)) {
@@ -993,6 +999,7 @@ static void lpuart_copy_rx_to_tty(struct lpuart_port *sport)
        struct tty_port *port = &sport->port.state->port;
        struct dma_tx_state state;
        enum dma_status dmastat;
+       struct dma_chan *chan = sport->dma_rx_chan;
        struct circ_buf *ring = &sport->rx_ring;
        unsigned long flags;
        int count = 0;
@@ -1053,10 +1060,7 @@ static void lpuart_copy_rx_to_tty(struct lpuart_port *sport)
 
        spin_lock_irqsave(&sport->port.lock, flags);
 
-       dmastat = dmaengine_tx_status(sport->dma_rx_chan,
-                               sport->dma_rx_cookie,
-                               &state);
-
+       dmastat = dmaengine_tx_status(chan, sport->dma_rx_cookie, &state);
        if (dmastat == DMA_ERROR) {
                dev_err(sport->port.dev, "Rx DMA transfer failed!\n");
                spin_unlock_irqrestore(&sport->port.lock, flags);
@@ -1064,7 +1068,8 @@ static void lpuart_copy_rx_to_tty(struct lpuart_port *sport)
        }
 
        /* CPU claims ownership of RX DMA buffer */
-       dma_sync_sg_for_cpu(sport->port.dev, &sport->rx_sgl, 1, DMA_FROM_DEVICE);
+       dma_sync_sg_for_cpu(chan->device->dev, &sport->rx_sgl, 1,
+                           DMA_FROM_DEVICE);
 
        /*
         * ring->head points to the end of data already written by the DMA.
@@ -1106,7 +1111,7 @@ static void lpuart_copy_rx_to_tty(struct lpuart_port *sport)
                sport->port.icount.rx += count;
        }
 
-       dma_sync_sg_for_device(sport->port.dev, &sport->rx_sgl, 1,
+       dma_sync_sg_for_device(chan->device->dev, &sport->rx_sgl, 1,
                               DMA_FROM_DEVICE);
 
        spin_unlock_irqrestore(&sport->port.lock, flags);
@@ -1138,6 +1143,7 @@ static inline int lpuart_start_rx_dma(struct lpuart_port *sport)
        struct tty_port *port = &sport->port.state->port;
        struct tty_struct *tty = port->tty;
        struct ktermios *termios = &tty->termios;
+       struct dma_chan *chan = sport->dma_rx_chan;
 
        baud = tty_get_baud_rate(tty);
 
@@ -1159,7 +1165,8 @@ static inline int lpuart_start_rx_dma(struct lpuart_port *sport)
                return -ENOMEM;
 
        sg_init_one(&sport->rx_sgl, ring->buf, sport->rx_dma_rng_buf_len);
-       nent = dma_map_sg(sport->port.dev, &sport->rx_sgl, 1, DMA_FROM_DEVICE);
+       nent = dma_map_sg(chan->device->dev, &sport->rx_sgl, 1,
+                         DMA_FROM_DEVICE);
 
        if (!nent) {
                dev_err(sport->port.dev, "DMA Rx mapping error\n");
@@ -1170,7 +1177,7 @@ static inline int lpuart_start_rx_dma(struct lpuart_port *sport)
        dma_rx_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
        dma_rx_sconfig.src_maxburst = 1;
        dma_rx_sconfig.direction = DMA_DEV_TO_MEM;
-       ret = dmaengine_slave_config(sport->dma_rx_chan, &dma_rx_sconfig);
+       ret = dmaengine_slave_config(chan, &dma_rx_sconfig);
 
        if (ret < 0) {
                dev_err(sport->port.dev,
@@ -1178,7 +1185,7 @@ static inline int lpuart_start_rx_dma(struct lpuart_port *sport)
                return ret;
        }
 
-       sport->dma_rx_desc = dmaengine_prep_dma_cyclic(sport->dma_rx_chan,
+       sport->dma_rx_desc = dmaengine_prep_dma_cyclic(chan,
                                 sg_dma_address(&sport->rx_sgl),
                                 sport->rx_sgl.length,
                                 sport->rx_sgl.length / 2,
@@ -1192,7 +1199,7 @@ static inline int lpuart_start_rx_dma(struct lpuart_port *sport)
        sport->dma_rx_desc->callback = lpuart_dma_rx_complete;
        sport->dma_rx_desc->callback_param = sport;
        sport->dma_rx_cookie = dmaengine_submit(sport->dma_rx_desc);
-       dma_async_issue_pending(sport->dma_rx_chan);
+       dma_async_issue_pending(chan);
 
        if (lpuart_is_32(sport)) {
                unsigned long temp = lpuart32_read(&sport->port, UARTBAUD);
@@ -1210,11 +1217,12 @@ static void lpuart_dma_rx_free(struct uart_port *port)
 {
        struct lpuart_port *sport = container_of(port,
                                        struct lpuart_port, port);
+       struct dma_chan *chan = sport->dma_rx_chan;
 
-       if (sport->dma_rx_chan)
-               dmaengine_terminate_all(sport->dma_rx_chan);
+       if (chan)
+               dmaengine_terminate_all(chan);
 
-       dma_unmap_sg(sport->port.dev, &sport->rx_sgl, 1, DMA_FROM_DEVICE);
+       dma_unmap_sg(chan->device->dev, &sport->rx_sgl, 1, DMA_FROM_DEVICE);
        kfree(sport->rx_ring.buf);
        sport->rx_ring.tail = 0;
        sport->rx_ring.head = 0;