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path: root/drivers/tty/serial/amba-pl011.c
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Diffstat (limited to 'drivers/tty/serial/amba-pl011.c')
-rw-r--r--drivers/tty/serial/amba-pl011.c71
1 files changed, 60 insertions, 11 deletions
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 9ae024025ff..0c65c9e6698 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -51,6 +51,7 @@
#include <linux/dma-mapping.h>
#include <linux/scatterlist.h>
#include <linux/delay.h>
+#include <linux/types.h>
#include <asm/io.h>
#include <asm/sizes.h>
@@ -159,6 +160,7 @@ struct uart_amba_port {
unsigned int fifosize; /* vendor-specific */
unsigned int lcrh_tx; /* vendor-specific */
unsigned int lcrh_rx; /* vendor-specific */
+ unsigned int old_cr; /* state during shutdown */
bool autorts;
char type[12];
bool interrupt_may_hang; /* vendor-specific */
@@ -270,6 +272,7 @@ static void pl011_dma_probe_initcall(struct uart_amba_port *uap)
.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
.direction = DMA_MEM_TO_DEV,
.dst_maxburst = uap->fifosize >> 1,
+ .device_fc = false,
};
struct dma_chan *chan;
dma_cap_mask_t mask;
@@ -303,6 +306,7 @@ static void pl011_dma_probe_initcall(struct uart_amba_port *uap)
.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
.direction = DMA_DEV_TO_MEM,
.src_maxburst = uap->fifosize >> 1,
+ .device_fc = false,
};
chan = dma_request_channel(mask, plat->dma_filter, plat->dma_rx_param);
@@ -480,7 +484,7 @@ static int pl011_dma_tx_refill(struct uart_amba_port *uap)
return -EBUSY;
}
- desc = dma_dev->device_prep_slave_sg(chan, &dmatx->sg, 1, DMA_MEM_TO_DEV,
+ desc = dmaengine_prep_slave_sg(chan, &dmatx->sg, 1, DMA_MEM_TO_DEV,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) {
dma_unmap_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE);
@@ -663,7 +667,6 @@ static void pl011_dma_rx_callback(void *data);
static int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap)
{
struct dma_chan *rxchan = uap->dmarx.chan;
- struct dma_device *dma_dev;
struct pl011_dmarx_data *dmarx = &uap->dmarx;
struct dma_async_tx_descriptor *desc;
struct pl011_sgbuf *sgbuf;
@@ -674,8 +677,7 @@ static int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap)
/* Start the RX DMA job */
sgbuf = uap->dmarx.use_buf_b ?
&uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
- dma_dev = rxchan->device;
- desc = rxchan->device->device_prep_slave_sg(rxchan, &sgbuf->sg, 1,
+ desc = dmaengine_prep_slave_sg(rxchan, &sgbuf->sg, 1,
DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
/*
@@ -826,7 +828,12 @@ static void pl011_dma_rx_callback(void *data)
{
struct uart_amba_port *uap = data;
struct pl011_dmarx_data *dmarx = &uap->dmarx;
+ struct dma_chan *rxchan = dmarx->chan;
bool lastbuf = dmarx->use_buf_b;
+ struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ?
+ &dmarx->sgbuf_b : &dmarx->sgbuf_a;
+ size_t pending;
+ struct dma_tx_state state;
int ret;
/*
@@ -837,11 +844,21 @@ static void pl011_dma_rx_callback(void *data)
* we immediately trigger the next DMA job.
*/
spin_lock_irq(&uap->port.lock);
+ /*
+ * Rx data can be taken by the UART interrupts during
+ * the DMA irq handler. So we check the residue here.
+ */
+ rxchan->device->device_tx_status(rxchan, dmarx->cookie, &state);
+ pending = sgbuf->sg.length - state.residue;
+ BUG_ON(pending > PL011_DMA_BUFFER_SIZE);
+ /* Then we terminate the transfer - we now know our residue */
+ dmaengine_terminate_all(rxchan);
+
uap->dmarx.running = false;
dmarx->use_buf_b = !lastbuf;
ret = pl011_dma_rx_trigger_dma(uap);
- pl011_dma_rx_chars(uap, PL011_DMA_BUFFER_SIZE, lastbuf, false);
+ pl011_dma_rx_chars(uap, pending, lastbuf, false);
spin_unlock_irq(&uap->port.lock);
/*
* Do this check after we picked the DMA chars so we don't
@@ -1380,6 +1397,10 @@ static int pl011_startup(struct uart_port *port)
uap->port.uartclk = clk_get_rate(uap->clk);
+ /* Clear pending error and receive interrupts */
+ writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS |
+ UART011_RTIS | UART011_RXIS, uap->port.membase + UART011_ICR);
+
/*
* Allocate the IRQ
*/
@@ -1411,13 +1432,11 @@ static int pl011_startup(struct uart_port *port)
while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY)
barrier();
- cr = UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE;
+ /* restore RTS and DTR */
+ cr = uap->old_cr & (UART011_CR_RTS | UART011_CR_DTR);
+ cr |= UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE;
writew(cr, uap->port.membase + UART011_CR);
- /* Clear pending error interrupts */
- writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS,
- uap->port.membase + UART011_ICR);
-
/*
* initialise the old status of the modem signals
*/
@@ -1432,6 +1451,9 @@ static int pl011_startup(struct uart_port *port)
* as well.
*/
spin_lock_irq(&uap->port.lock);
+ /* Clear out any spuriously appearing RX interrupts */
+ writew(UART011_RTIS | UART011_RXIS,
+ uap->port.membase + UART011_ICR);
uap->im = UART011_RTIM;
if (!pl011_dma_rx_running(uap))
uap->im |= UART011_RXIM;
@@ -1469,6 +1491,7 @@ static void pl011_shutdown_channel(struct uart_amba_port *uap,
static void pl011_shutdown(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
+ unsigned int cr;
/*
* disable all interrupts
@@ -1488,9 +1511,16 @@ static void pl011_shutdown(struct uart_port *port)
/*
* disable the port
+ * disable the port. It should not disable RTS and DTR.
+ * Also RTS and DTR state should be preserved to restore
+ * it during startup().
*/
uap->autorts = false;
- writew(UART01x_CR_UARTEN | UART011_CR_TXE, uap->port.membase + UART011_CR);
+ cr = readw(uap->port.membase + UART011_CR);
+ uap->old_cr = cr;
+ cr &= UART011_CR_RTS | UART011_CR_DTR;
+ cr |= UART01x_CR_UARTEN | UART011_CR_TXE;
+ writew(cr, uap->port.membase + UART011_CR);
/*
* disable break condition and fifos
@@ -1740,9 +1770,19 @@ pl011_console_write(struct console *co, const char *s, unsigned int count)
{
struct uart_amba_port *uap = amba_ports[co->index];
unsigned int status, old_cr, new_cr;
+ unsigned long flags;
+ int locked = 1;
clk_enable(uap->clk);
+ local_irq_save(flags);
+ if (uap->port.sysrq)
+ locked = 0;
+ else if (oops_in_progress)
+ locked = spin_trylock(&uap->port.lock);
+ else
+ spin_lock(&uap->port.lock);
+
/*
* First save the CR then disable the interrupts
*/
@@ -1762,6 +1802,10 @@ pl011_console_write(struct console *co, const char *s, unsigned int count)
} while (status & UART01x_FR_BUSY);
writew(old_cr, uap->port.membase + UART011_CR);
+ if (locked)
+ spin_unlock(&uap->port.lock);
+ local_irq_restore(flags);
+
clk_disable(uap->clk);
}
@@ -1902,9 +1946,14 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
goto unmap;
}
+ /* Ensure interrupts from this UART are masked and cleared */
+ writew(0, uap->port.membase + UART011_IMSC);
+ writew(0xffff, uap->port.membase + UART011_ICR);
+
uap->vendor = vendor;
uap->lcrh_rx = vendor->lcrh_rx;
uap->lcrh_tx = vendor->lcrh_tx;
+ uap->old_cr = 0;
uap->fifosize = vendor->fifosize;
uap->interrupt_may_hang = vendor->interrupt_may_hang;
uap->port.dev = &dev->dev;
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-31 23:14:21 +0000