Using fake IIR values to perform rx dma operations unnecessarily
conflates separate operations, stopping in-progress dma with starting
new dma.
Introduce serial8250_rx_dma_flush() to handle stopping in-progress dma
[omap8250 already has equivalent omap_8250_rx_dma_flush()].
Replace rx_dma(UART_IIR_RX_TIMEOUT) with the equivalent *_rx_dma_flush(),
and rx_dma(0) with the equivalent *_rx_dma(). Handle IIR steering
in the irq handler with handle_rx_dma() helper.
Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/8250/8250.h | 8 +++--
drivers/tty/serial/8250/8250_dma.c | 32 +++++++-----------
drivers/tty/serial/8250/8250_omap.c | 67 ++++++++++++++++---------------------
drivers/tty/serial/8250/8250_port.c | 14 +++++++-
4 files changed, 58 insertions(+), 63 deletions(-)
diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index 8739d22..7a4c826 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -17,7 +17,7 @@
struct uart_8250_dma {
int (*tx_dma)(struct uart_8250_port *p);
- int (*rx_dma)(struct uart_8250_port *p, unsigned int iir);
+ int (*rx_dma)(struct uart_8250_port *p);
/* Filter function */
dma_filter_fn fn;
@@ -189,7 +189,8 @@ static inline int is_omap1510_8250(struct uart_8250_port *pt)
#ifdef CONFIG_SERIAL_8250_DMA
extern int serial8250_tx_dma(struct uart_8250_port *);
-extern int serial8250_rx_dma(struct uart_8250_port *, unsigned int iir);
+extern int serial8250_rx_dma(struct uart_8250_port *);
+extern void serial8250_rx_dma_flush(struct uart_8250_port *);
extern int serial8250_request_dma(struct uart_8250_port *);
extern void serial8250_release_dma(struct uart_8250_port *);
#else
@@ -197,10 +198,11 @@ static inline int serial8250_tx_dma(struct uart_8250_port *p)
{
return -1;
}
-static inline int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
+static inline int serial8250_rx_dma(struct uart_8250_port *p)
{
return -1;
}
+static inline void serial8250_rx_dma_flush(struct uart_8250_port *p) { }
static inline int serial8250_request_dma(struct uart_8250_port *p)
{
return -1;
diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
index 7a26c4d..7f33d1c 100644
--- a/drivers/tty/serial/8250/8250_dma.c
+++ b/drivers/tty/serial/8250/8250_dma.c
@@ -110,30 +110,11 @@ err:
return ret;
}
-int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
+int serial8250_rx_dma(struct uart_8250_port *p)
{
struct uart_8250_dma *dma = p->dma;
struct dma_async_tx_descriptor *desc;
- switch (iir & 0x3f) {
- case UART_IIR_RLSI:
- /* 8250_core handles errors and break interrupts */
- return -EIO;
- case UART_IIR_RX_TIMEOUT:
- /*
- * If RCVR FIFO trigger level was not reached, complete the
- * transfer and let 8250_core copy the remaining data.
- */
- if (dma->rx_running) {
- dmaengine_pause(dma->rxchan);
- __dma_rx_complete(p);
- dmaengine_terminate_all(dma->rxchan);
- }
- return -ETIMEDOUT;
- default:
- break;
- }
-
if (dma->rx_running)
return 0;
@@ -154,6 +135,17 @@ int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
return 0;
}
+void serial8250_rx_dma_flush(struct uart_8250_port *p)
+{
+ struct uart_8250_dma *dma = p->dma;
+
+ if (dma->rx_running) {
+ dmaengine_pause(dma->rxchan);
+ __dma_rx_complete(p);
+ dmaengine_terminate_all(dma->rxchan);
+ }
+}
+
int serial8250_request_dma(struct uart_8250_port *p)
{
struct uart_8250_dma *dma = p->dma;
diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index 27702d5..8579b0c 100644
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -115,6 +115,12 @@ struct omap8250_priv {
bool rx_dma_broken;
};
+#ifdef CONFIG_SERIAL_8250_DMA
+static void omap_8250_rx_dma_flush(struct uart_8250_port *p);
+#else
+static inline void omap_8250_rx_dma_flush(struct uart_8250_port *p) { }
+#endif
+
static u32 uart_read(struct uart_8250_port *up, u32 reg)
{
return readl(up->port.membase + (reg << up->port.regshift));
@@ -635,7 +641,7 @@ static int omap_8250_startup(struct uart_port *port)
serial_out(up, UART_OMAP_WER, priv->wer);
if (up->dma)
- up->dma->rx_dma(up, 0);
+ up->dma->rx_dma(up);
pm_runtime_mark_last_busy(port->dev);
pm_runtime_put_autosuspend(port->dev);
@@ -654,7 +660,7 @@ static void omap_8250_shutdown(struct uart_port *port)
flush_work(&priv->qos_work);
if (up->dma)
- up->dma->rx_dma(up, UART_IIR_RX_TIMEOUT);
+ omap_8250_rx_dma_flush(up);
pm_runtime_get_sync(port->dev);
@@ -742,7 +748,7 @@ static void omap_8250_unthrottle(struct uart_port *port)
}
#ifdef CONFIG_SERIAL_8250_DMA
-static int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir);
+static int omap_8250_rx_dma(struct uart_8250_port *p);
static void __dma_rx_do_complete(struct uart_8250_port *p)
{
@@ -778,7 +784,7 @@ unlock:
static void __dma_rx_complete(void *param)
{
__dma_rx_do_complete(param);
- omap_8250_rx_dma(param, 0);
+ omap_8250_rx_dma(param);
}
static void omap_8250_rx_dma_flush(struct uart_8250_port *p)
@@ -804,7 +810,7 @@ static void omap_8250_rx_dma_flush(struct uart_8250_port *p)
__dma_rx_do_complete(p);
}
-static int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
+static int omap_8250_rx_dma(struct uart_8250_port *p)
{
struct omap8250_priv *priv = p->port.private_data;
struct uart_8250_dma *dma = p->dma;
@@ -812,35 +818,6 @@ static int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
struct dma_async_tx_descriptor *desc;
unsigned long flags;
- switch (iir & 0x3f) {
- case UART_IIR_RLSI:
- /* 8250_core handles errors and break interrupts */
- omap_8250_rx_dma_flush(p);
- return -EIO;
- case UART_IIR_RX_TIMEOUT:
- /*
- * If RCVR FIFO trigger level was not reached, complete the
- * transfer and let 8250_core copy the remaining data.
- */
- omap_8250_rx_dma_flush(p);
- return -ETIMEDOUT;
- case UART_IIR_RDI:
- /*
- * The OMAP UART is a special BEAST. If we receive RDI we _have_
- * a DMA transfer programmed but it didn't work. One reason is
- * that we were too slow and there were too many bytes in the
- * FIFO, the UART counted wrong and never kicked the DMA engine
- * to do anything. That means once we receive RDI on OMAP then
- * the DMA won't do anything soon so we have to cancel the DMA
- * transfer and purge the FIFO manually.
- */
- omap_8250_rx_dma_flush(p);
- return -ETIMEDOUT;
-
- default:
- break;
- }
-
if (priv->rx_dma_broken)
return -EINVAL;
@@ -1014,6 +991,18 @@ err:
return ret;
}
+static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir)
+{
+ switch (iir & 0x3f) {
+ case UART_IIR_RLSI:
+ case UART_IIR_RX_TIMEOUT:
+ case UART_IIR_RDI:
+ omap_8250_rx_dma_flush(up);
+ return true;
+ }
+ return omap_8250_rx_dma(up);
+}
+
/*
* This is mostly serial8250_handle_irq(). We have a slightly different DMA
* hoook for RX/TX and need different logic for them in the ISR. Therefore we
@@ -1039,9 +1028,9 @@ static int omap_8250_dma_handle_irq(struct uart_port *port)
status = serial_port_in(port, UART_LSR);
if (status & (UART_LSR_DR | UART_LSR_BI)) {
- if (omap_8250_rx_dma(up, iir)) {
+ if (handle_rx_dma(up, iir)) {
status = serial8250_rx_chars(up, status);
- omap_8250_rx_dma(up, 0);
+ omap_8250_rx_dma(up);
}
}
serial8250_modem_status(up);
@@ -1072,7 +1061,7 @@ static bool the_no_dma_filter_fn(struct dma_chan *chan, void *param)
#else
-static inline int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
+static inline int omap_8250_rx_dma(struct uart_8250_port *p)
{
return -EINVAL;
}
@@ -1383,7 +1372,7 @@ static int omap8250_runtime_suspend(struct device *dev)
}
if (up->dma && up->dma->rxchan)
- omap_8250_rx_dma(up, UART_IIR_RX_TIMEOUT);
+ omap_8250_rx_dma_flush(up);
priv->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
schedule_work(&priv->qos_work);
@@ -1406,7 +1395,7 @@ static int omap8250_runtime_resume(struct device *dev)
omap8250_restore_regs(up);
if (up->dma && up->dma->rxchan)
- omap_8250_rx_dma(up, 0);
+ omap_8250_rx_dma(up);
priv->latency = priv->calc_latency;
schedule_work(&priv->qos_work);
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index bcc9535..c9addd9 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1779,6 +1779,18 @@ unsigned int serial8250_modem_status(struct uart_8250_port *up)
}
EXPORT_SYMBOL_GPL(serial8250_modem_status);
+static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir)
+{
+ switch (iir & 0x3f) {
+ case UART_IIR_RX_TIMEOUT:
+ serial8250_rx_dma_flush(up);
+ /* fall-through */
+ case UART_IIR_RLSI:
+ return true;
+ }
+ return up->dma->rx_dma(up);
+}
+
/*
* This handles the interrupt from one port.
*/
@@ -1798,7 +1810,7 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
DEBUG_INTR("status = %x...", status);
if (status & (UART_LSR_DR | UART_LSR_BI)) {
- if (!up->dma || up->dma->rx_dma(up, iir))
+ if (!up->dma || handle_rx_dma(up, iir))
status = serial8250_rx_chars(up, status);
}
serial8250_modem_status(up);
--
2.8.1
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