serial: amba-pl011: Use port lock wrappers

When a serial port is used for kernel console output, then all
modifications to the UART registers which are done from other contexts,
e.g. getty, termios, are interference points for the kernel console.

So far this has been ignored and the printk output is based on the
principle of hope. The rework of the console infrastructure which aims to
support threaded and atomic consoles, requires to mark sections which
modify the UART registers as unsafe. This allows the atomic write function
to make informed decisions and eventually to restore operational state. It
also allows to prevent the regular UART code from modifying UART registers
while printk output is in progress.

All modifications of UART registers are guarded by the UART port lock,
which provides an obvious synchronization point with the console
infrastructure.

To avoid adding this functionality to all UART drivers, wrap the
spin_[un]lock*() invocations for uart_port::lock into helper functions
which just contain the spin_[un]lock*() invocations for now. In a
subsequent step these helpers will gain the console synchronization
mechanisms.

Converted with coccinelle. No functional change.

Signed-off-by: Thomas Gleixner <[e-mail]>
Signed-off-by: John Ogness <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/serial/amba-pl011.c

···
 				flag = TTY_FRAME;
 		}
 
-		spin_unlock(&uap->port.lock);
+		uart_port_unlock(&uap->port);
 		sysrq = uart_handle_sysrq_char(&uap->port, ch & 255);
-		spin_lock(&uap->port.lock);
+		uart_port_lock(&uap->port);
 
 		if (!sysrq)
 			uart_insert_char(&uap->port, ch, UART011_DR_OE, ch, flag);
···
 	unsigned long flags;
 	u16 dmacr;
 
-	spin_lock_irqsave(&uap->port.lock, flags);
+	uart_port_lock_irqsave(&uap->port, &flags);
 	if (uap->dmatx.queued)
 		dma_unmap_sg(dmatx->chan->device->dev, &dmatx->sg, 1,
 			     DMA_TO_DEVICE);
···
 	if (!(dmacr & UART011_TXDMAE) || uart_tx_stopped(&uap->port) ||
 	    uart_circ_empty(&uap->port.state->xmit)) {
 		uap->dmatx.queued = false;
-		spin_unlock_irqrestore(&uap->port.lock, flags);
+		uart_port_unlock_irqrestore(&uap->port, flags);
 		return;
 	}
 
···
 		 */
 		pl011_start_tx_pio(uap);
 
-	spin_unlock_irqrestore(&uap->port.lock, flags);
+	uart_port_unlock_irqrestore(&uap->port, flags);
 }
 
 /*
···
 	 * routine to flush out the secondary DMA buffer while
 	 * we immediately trigger the next DMA job.
 	 */
-	spin_lock_irq(&uap->port.lock);
+	uart_port_lock_irq(&uap->port);
 	/*
 	 * Rx data can be taken by the UART interrupts during
 	 * the DMA irq handler. So we check the residue here.
···
 	ret = pl011_dma_rx_trigger_dma(uap);
 
 	pl011_dma_rx_chars(uap, pending, lastbuf, false);
-	spin_unlock_irq(&uap->port.lock);
+	uart_port_unlock_irq(&uap->port);
 	/*
 	 * Do this check after we picked the DMA chars so we don't
 	 * get some IRQ immediately from RX.
···
 	if (jiffies_to_msecs(jiffies - dmarx->last_jiffies)
 			> uap->dmarx.poll_timeout) {
 
-		spin_lock_irqsave(&uap->port.lock, flags);
+		uart_port_lock_irqsave(&uap->port, &flags);
 		pl011_dma_rx_stop(uap);
 		uap->im |= UART011_RXIM;
 		pl011_write(uap->im, uap, REG_IMSC);
-		spin_unlock_irqrestore(&uap->port.lock, flags);
+		uart_port_unlock_irqrestore(&uap->port, flags);
 
 		uap->dmarx.running = false;
 		dmaengine_terminate_all(rxchan);
···
 	while (pl011_read(uap, REG_FR) & uap->vendor->fr_busy)
 		cpu_relax();
 
-	spin_lock_irq(&uap->port.lock);
+	uart_port_lock_irq(&uap->port);
 	uap->dmacr &= ~(UART011_DMAONERR | UART011_RXDMAE | UART011_TXDMAE);
 	pl011_write(uap->dmacr, uap, REG_DMACR);
-	spin_unlock_irq(&uap->port.lock);
+	uart_port_unlock_irq(&uap->port);
 
 	if (uap->using_tx_dma) {
 		/* In theory, this should already be done by pl011_dma_flush_buffer */
···
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&port->lock, flags);
+	uart_port_lock_irqsave(port, &flags);
 	pl011_stop_rx(port);
-	spin_unlock_irqrestore(&port->lock, flags);
+	uart_port_unlock_irqrestore(port, flags);
 }
 
 static void pl011_enable_ms(struct uart_port *port)
···
 {
 	pl011_fifo_to_tty(uap);
 
-	spin_unlock(&uap->port.lock);
+	uart_port_unlock(&uap->port);
 	tty_flip_buffer_push(&uap->port.state->port);
 	/*
 	 * If we were temporarily out of DMA mode for a while,
···
 #endif
 		}
 	}
-	spin_lock(&uap->port.lock);
+	uart_port_lock(&uap->port);
 }
 
 static bool pl011_tx_char(struct uart_amba_port *uap, unsigned char c,
···
 	unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
 	int handled = 0;
 
-	spin_lock_irqsave(&uap->port.lock, flags);
+	uart_port_lock_irqsave(&uap->port, &flags);
 	status = pl011_read(uap, REG_RIS) & uap->im;
 	if (status) {
 		do {
···
 		handled = 1;
 	}
 
-	spin_unlock_irqrestore(&uap->port.lock, flags);
+	uart_port_unlock_irqrestore(&uap->port, flags);
 
 	return IRQ_RETVAL(handled);
 }
···
 	unsigned long flags;
 	unsigned int lcr_h;
 
-	spin_lock_irqsave(&uap->port.lock, flags);
+	uart_port_lock_irqsave(&uap->port, &flags);
 	lcr_h = pl011_read(uap, REG_LCRH_TX);
 	if (break_state == -1)
 		lcr_h |= UART01x_LCRH_BRK;
 	else
 		lcr_h &= ~UART01x_LCRH_BRK;
 	pl011_write(lcr_h, uap, REG_LCRH_TX);
-	spin_unlock_irqrestore(&uap->port.lock, flags);
+	uart_port_unlock_irqrestore(&uap->port, flags);
 }
 
 #ifdef CONFIG_CONSOLE_POLL
···
 	unsigned long flags;
 	unsigned int i;
 
-	spin_lock_irqsave(&uap->port.lock, flags);
+	uart_port_lock_irqsave(&uap->port, &flags);
 
 	/* Clear out any spuriously appearing RX interrupts */
 	pl011_write(UART011_RTIS | UART011_RXIS, uap, REG_ICR);
···
 	if (!pl011_dma_rx_running(uap))
 		uap->im |= UART011_RXIM;
 	pl011_write(uap->im, uap, REG_IMSC);
-	spin_unlock_irqrestore(&uap->port.lock, flags);
+	uart_port_unlock_irqrestore(&uap->port, flags);
 }
 
 static void pl011_unthrottle_rx(struct uart_port *port)
···
 	struct uart_amba_port *uap = container_of(port, struct uart_amba_port, port);
 	unsigned long flags;
 
-	spin_lock_irqsave(&uap->port.lock, flags);
+	uart_port_lock_irqsave(&uap->port, &flags);
 
 	uap->im = UART011_RTIM;
 	if (!pl011_dma_rx_running(uap))
···
 
 	pl011_write(uap->im, uap, REG_IMSC);
 
-	spin_unlock_irqrestore(&uap->port.lock, flags);
+	uart_port_unlock_irqrestore(&uap->port, flags);
 }
 
 static int pl011_startup(struct uart_port *port)
···
 
 	pl011_write(uap->vendor->ifls, uap, REG_IFLS);
 
-	spin_lock_irq(&uap->port.lock);
+	uart_port_lock_irq(&uap->port);
 
 	cr = pl011_read(uap, REG_CR);
 	cr &= UART011_CR_RTS | UART011_CR_DTR;
···
 
 	pl011_write(cr, uap, REG_CR);
 
-	spin_unlock_irq(&uap->port.lock);
+	uart_port_unlock_irq(&uap->port);
 
 	/*
 	 * initialise the old status of the modem signals
···
 	unsigned int cr;
 
 	uap->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS);
-	spin_lock_irq(&uap->port.lock);
+	uart_port_lock_irq(&uap->port);
 	cr = pl011_read(uap, REG_CR);
 	cr &= UART011_CR_RTS | UART011_CR_DTR;
 	cr |= UART01x_CR_UARTEN | UART011_CR_TXE;
 	pl011_write(cr, uap, REG_CR);
-	spin_unlock_irq(&uap->port.lock);
+	uart_port_unlock_irq(&uap->port);
 
 	/*
 	 * disable break condition and fifos
···
 
 static void pl011_disable_interrupts(struct uart_amba_port *uap)
 {
-	spin_lock_irq(&uap->port.lock);
+	uart_port_lock_irq(&uap->port);
 
 	/* mask all interrupts and clear all pending ones */
 	uap->im = 0;
 	pl011_write(uap->im, uap, REG_IMSC);
 	pl011_write(0xffff, uap, REG_ICR);
 
-	spin_unlock_irq(&uap->port.lock);
+	uart_port_unlock_irq(&uap->port);
 }
 
 static void pl011_shutdown(struct uart_port *port)
···
 
 	bits = tty_get_frame_size(termios->c_cflag);
 
-	spin_lock_irqsave(&port->lock, flags);
+	uart_port_lock_irqsave(port, &flags);
 
 	/*
 	 * Update the per-port timeout.
···
 	old_cr |= UART011_CR_RXE;
 	pl011_write(old_cr, uap, REG_CR);
 
-	spin_unlock_irqrestore(&port->lock, flags);
+	uart_port_unlock_irqrestore(port, flags);
 }
 
 static void
···
 	termios->c_cflag &= ~(CMSPAR | CRTSCTS);
 	termios->c_cflag |= CS8 | CLOCAL;
 
-	spin_lock_irqsave(&port->lock, flags);
+	uart_port_lock_irqsave(port, &flags);
 	uart_update_timeout(port, CS8, uap->fixed_baud);
 	pl011_setup_status_masks(port, termios);
-	spin_unlock_irqrestore(&port->lock, flags);
+	uart_port_unlock_irqrestore(port, flags);
 }
 
 static const char *pl011_type(struct uart_port *port)
···
 	if (uap->port.sysrq)
 		locked = 0;
 	else if (oops_in_progress)
-		locked = spin_trylock(&uap->port.lock);
+		locked = uart_port_trylock(&uap->port);
 	else
-		spin_lock(&uap->port.lock);
+		uart_port_lock(&uap->port);
 
 	/*
 	 *	First save the CR then disable the interrupts
···
 		pl011_write(old_cr, uap, REG_CR);
 
 	if (locked)
-		spin_unlock(&uap->port.lock);
+		uart_port_unlock(&uap->port);
 	local_irq_restore(flags);
 
 	clk_disable(uap->clk);