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-rw-r--r--drivers/tty/serial/serial-tegra.c78
1 files changed, 46 insertions, 32 deletions
diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c
index b6ace6290e23..3b495e7c9534 100644
--- a/drivers/tty/serial/serial-tegra.c
+++ b/drivers/tty/serial/serial-tegra.c
@@ -141,6 +141,7 @@ struct tegra_uart_port {
int configured_rate;
bool use_rx_pio;
bool use_tx_pio;
+ bool rx_dma_active;
};
static void tegra_uart_start_next_tx(struct tegra_uart_port *tup);
@@ -731,6 +732,7 @@ static void tegra_uart_rx_dma_complete(void *args)
if (tup->rts_active)
set_rts(tup, false);
+ tup->rx_dma_active = false;
tegra_uart_rx_buffer_push(tup, 0);
tegra_uart_start_rx_dma(tup);
@@ -742,18 +744,27 @@ done:
spin_unlock_irqrestore(&u->lock, flags);
}
-static void tegra_uart_handle_rx_dma(struct tegra_uart_port *tup)
+static void tegra_uart_terminate_rx_dma(struct tegra_uart_port *tup)
{
struct dma_tx_state state;
- /* Deactivate flow control to stop sender */
- if (tup->rts_active)
- set_rts(tup, false);
+ if (!tup->rx_dma_active)
+ return;
dmaengine_terminate_all(tup->rx_dma_chan);
dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
+
tegra_uart_rx_buffer_push(tup, state.residue);
- tegra_uart_start_rx_dma(tup);
+ tup->rx_dma_active = false;
+}
+
+static void tegra_uart_handle_rx_dma(struct tegra_uart_port *tup)
+{
+ /* Deactivate flow control to stop sender */
+ if (tup->rts_active)
+ set_rts(tup, false);
+
+ tegra_uart_terminate_rx_dma(tup);
if (tup->rts_active)
set_rts(tup, true);
@@ -763,6 +774,9 @@ static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup)
{
unsigned int count = TEGRA_UART_RX_DMA_BUFFER_SIZE;
+ if (tup->rx_dma_active)
+ return 0;
+
tup->rx_dma_desc = dmaengine_prep_slave_single(tup->rx_dma_chan,
tup->rx_dma_buf_phys, count, DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT);
@@ -771,6 +785,7 @@ static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup)
return -EIO;
}
+ tup->rx_dma_active = true;
tup->rx_dma_desc->callback = tegra_uart_rx_dma_complete;
tup->rx_dma_desc->callback_param = tup;
dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys,
@@ -820,6 +835,7 @@ static irqreturn_t tegra_uart_isr(int irq, void *data)
struct uart_port *u = &tup->uport;
unsigned long iir;
unsigned long ier;
+ bool is_rx_start = false;
bool is_rx_int = false;
unsigned long flags;
@@ -832,10 +848,12 @@ static irqreturn_t tegra_uart_isr(int irq, void *data)
if (tup->rx_in_progress) {
ier = tup->ier_shadow;
ier |= (UART_IER_RLSI | UART_IER_RTOIE |
- TEGRA_UART_IER_EORD);
+ TEGRA_UART_IER_EORD | UART_IER_RDI);
tup->ier_shadow = ier;
tegra_uart_write(tup, ier, UART_IER);
}
+ } else if (is_rx_start) {
+ tegra_uart_start_rx_dma(tup);
}
spin_unlock_irqrestore(&u->lock, flags);
return IRQ_HANDLED;
@@ -854,17 +872,23 @@ static irqreturn_t tegra_uart_isr(int irq, void *data)
case 4: /* End of data */
case 6: /* Rx timeout */
- case 2: /* Receive */
- if (!tup->use_rx_pio && !is_rx_int) {
- is_rx_int = true;
+ if (!tup->use_rx_pio) {
+ is_rx_int = tup->rx_in_progress;
/* Disable Rx interrupts */
ier = tup->ier_shadow;
- ier |= UART_IER_RDI;
- tegra_uart_write(tup, ier, UART_IER);
ier &= ~(UART_IER_RDI | UART_IER_RLSI |
UART_IER_RTOIE | TEGRA_UART_IER_EORD);
tup->ier_shadow = ier;
tegra_uart_write(tup, ier, UART_IER);
+ break;
+ }
+ /* Fall through */
+ case 2: /* Receive */
+ if (!tup->use_rx_pio) {
+ is_rx_start = tup->rx_in_progress;
+ tup->ier_shadow &= ~UART_IER_RDI;
+ tegra_uart_write(tup, tup->ier_shadow,
+ UART_IER);
} else {
do_handle_rx_pio(tup);
}
@@ -886,7 +910,6 @@ static void tegra_uart_stop_rx(struct uart_port *u)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
struct tty_port *port = &tup->uport.state->port;
- struct dma_tx_state state;
unsigned long ier;
if (tup->rts_active)
@@ -903,13 +926,11 @@ static void tegra_uart_stop_rx(struct uart_port *u)
tup->ier_shadow = ier;
tegra_uart_write(tup, ier, UART_IER);
tup->rx_in_progress = 0;
- if (tup->rx_dma_chan && !tup->use_rx_pio) {
- dmaengine_terminate_all(tup->rx_dma_chan);
- dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
- tegra_uart_rx_buffer_push(tup, state.residue);
- } else {
+
+ if (!tup->use_rx_pio)
+ tegra_uart_terminate_rx_dma(tup);
+ else
tegra_uart_handle_rx_pio(tup, port);
- }
}
static void tegra_uart_hw_deinit(struct tegra_uart_port *tup)
@@ -1052,12 +1073,6 @@ static int tegra_uart_hw_init(struct tegra_uart_port *tup)
tup->lcr_shadow = TEGRA_UART_DEFAULT_LSR;
tup->fcr_shadow |= UART_FCR_DMA_SELECT;
tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
-
- ret = tegra_uart_start_rx_dma(tup);
- if (ret < 0) {
- dev_err(tup->uport.dev, "Not able to start Rx DMA\n");
- return ret;
- }
} else {
tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
}
@@ -1067,10 +1082,6 @@ static int tegra_uart_hw_init(struct tegra_uart_port *tup)
* Enable IE_RXS for the receive status interrupts like line errros.
* Enable IE_RX_TIMEOUT to get the bytes which cannot be DMA'd.
*
- * If using DMA mode, enable EORD instead of receive interrupt which
- * will interrupt after the UART is done with the receive instead of
- * the interrupt when the FIFO "threshold" is reached.
- *
* EORD is different interrupt than RX_TIMEOUT - RX_TIMEOUT occurs when
* the DATA is sitting in the FIFO and couldn't be transferred to the
* DMA as the DMA size alignment (4 bytes) is not met. EORD will be
@@ -1081,11 +1092,14 @@ static int tegra_uart_hw_init(struct tegra_uart_port *tup)
* both the EORD as well as RX_TIMEOUT - SW sees RX_TIMEOUT first
* then the EORD.
*/
+ tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE | UART_IER_RDI;
+
+ /*
+ * If using DMA mode, enable EORD interrupt to notify about RX
+ * completion.
+ */
if (!tup->use_rx_pio)
- tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE |
- TEGRA_UART_IER_EORD;
- else
- tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE | UART_IER_RDI;
+ tup->ier_shadow |= TEGRA_UART_IER_EORD;
tegra_uart_write(tup, tup->ier_shadow, UART_IER);
return 0;
generated by cgit v1.2.3 (git 2.25.1) at 2025-02-06 19:10:36 +0000