@@ -71,6 +71,18 @@ properties:
received, and that the peripheral should invert its input using the
INVR registers.
+ fsl,dma-info:
+ $ref: /schemas/types.yaml#/definitions/uint32-array
+ minItems: 2
+ maxItems: 2
+ description: |
+ First cell contains the size of DMA buffer chunks, second cell contains
+ the amount of chunks used for the device. Multiplying both numbers is
+ the total size of memory used for receiving data.
+ When not being configured the system will use default settings, which
+ are sensible for most use cases. If you need low latency processing on
+ slow connections this needs to be configured appropriately.
+
uart-has-rtscts: true
rs485-rts-delay: true
@@ -225,6 +225,8 @@ struct imx_port {
struct scatterlist rx_sgl, tx_sgl[2];
void *rx_buf;
struct circ_buf rx_ring;
+ unsigned int rx_buf_size;
+ unsigned int rx_period_length;
unsigned int rx_periods;
dma_cookie_t rx_cookie;
unsigned int tx_bytes;
@@ -1183,10 +1185,6 @@ static void imx_uart_dma_rx_callback(void *data)
}
}
-/* RX DMA buffer periods */
-#define RX_DMA_PERIODS 16
-#define RX_BUF_SIZE (RX_DMA_PERIODS * PAGE_SIZE / 4)
-
static int imx_uart_start_rx_dma(struct imx_port *sport)
{
struct scatterlist *sgl = &sport->rx_sgl;
@@ -1197,9 +1195,8 @@ static int imx_uart_start_rx_dma(struct imx_port *sport)
sport->rx_ring.head = 0;
sport->rx_ring.tail = 0;
- sport->rx_periods = RX_DMA_PERIODS;
- sg_init_one(sgl, sport->rx_buf, RX_BUF_SIZE);
+ sg_init_one(sgl, sport->rx_buf, sport->rx_buf_size);
ret = dma_map_sg(dev, sgl, 1, DMA_FROM_DEVICE);
if (ret == 0) {
dev_err(dev, "DMA mapping error for RX.\n");
@@ -1316,7 +1313,8 @@ static int imx_uart_dma_init(struct imx_port *sport)
goto err;
}
- sport->rx_buf = kzalloc(RX_BUF_SIZE, GFP_KERNEL);
+ sport->rx_buf_size = sport->rx_period_length * sport->rx_periods;
+ sport->rx_buf = kzalloc(sport->rx_buf_size, GFP_KERNEL);
if (!sport->rx_buf) {
ret = -ENOMEM;
goto err;
@@ -2179,11 +2177,16 @@ static enum hrtimer_restart imx_trigger_stop_tx(struct hrtimer *t)
return HRTIMER_NORESTART;
}
+/* Default RX DMA buffer configuration */
+#define RX_DMA_PERIODS 16
+#define RX_DMA_PERIOD_LEN (PAGE_SIZE / 4)
+
static int imx_uart_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct imx_port *sport;
void __iomem *base;
+ u32 dma_buf_conf[2];
int ret = 0;
u32 ucr1;
struct resource *res;
@@ -2218,6 +2221,14 @@ static int imx_uart_probe(struct platform_device *pdev)
if (of_get_property(np, "fsl,inverted-rx", NULL))
sport->inverted_rx = 1;
+ if (!of_property_read_u32_array(np, "fsl,dma-info", dma_buf_conf, 2)) {
+ sport->rx_period_length = dma_buf_conf[0];
+ sport->rx_periods = dma_buf_conf[1];
+ } else {
+ sport->rx_period_length = RX_DMA_PERIOD_LEN;
+ sport->rx_periods = RX_DMA_PERIODS;
+ }
+
if (sport->port.line >= ARRAY_SIZE(imx_uart_ports)) {
dev_err(&pdev->dev, "serial%d out of range\n",
sport->port.line);