Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 813 insertions, 0 deletions

diff --git a/drivers/tty/serial/rda-uart.c b/drivers/tty/serial/rda-uart.c
new file mode 100644
index 000000000..87fa30d68
--- /dev/null
+++ b/drivers/tty/serial/rda-uart.c
@@ -0,0 +1,813 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * RDA8810PL serial device driver
+ *
+ * Copyright RDA Microelectronics Company Limited
+ * Copyright (c) 2017 Andreas Färber
+ * Copyright (c) 2018 Manivannan Sadhasivam
+ */
+
+#include <linux/clk.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+
+#define RDA_UART_PORT_NUM 3
+#define RDA_UART_DEV_NAME "ttyRDA"
+
+#define RDA_UART_CTRL		0x00
+#define RDA_UART_STATUS		0x04
+#define RDA_UART_RXTX_BUFFER	0x08
+#define RDA_UART_IRQ_MASK	0x0c
+#define RDA_UART_IRQ_CAUSE	0x10
+#define RDA_UART_IRQ_TRIGGERS	0x14
+#define RDA_UART_CMD_SET	0x18
+#define RDA_UART_CMD_CLR	0x1c
+
+/* UART_CTRL Bits */
+#define RDA_UART_ENABLE			BIT(0)
+#define RDA_UART_DBITS_8		BIT(1)
+#define RDA_UART_TX_SBITS_2		BIT(2)
+#define RDA_UART_PARITY_EN		BIT(3)
+#define RDA_UART_PARITY(x)		(((x) & 0x3) << 4)
+#define RDA_UART_PARITY_ODD		RDA_UART_PARITY(0)
+#define RDA_UART_PARITY_EVEN		RDA_UART_PARITY(1)
+#define RDA_UART_PARITY_SPACE		RDA_UART_PARITY(2)
+#define RDA_UART_PARITY_MARK		RDA_UART_PARITY(3)
+#define RDA_UART_DIV_MODE		BIT(20)
+#define RDA_UART_IRDA_EN		BIT(21)
+#define RDA_UART_DMA_EN			BIT(22)
+#define RDA_UART_FLOW_CNT_EN		BIT(23)
+#define RDA_UART_LOOP_BACK_EN		BIT(24)
+#define RDA_UART_RX_LOCK_ERR		BIT(25)
+#define RDA_UART_RX_BREAK_LEN(x)	(((x) & 0xf) << 28)
+
+/* UART_STATUS Bits */
+#define RDA_UART_RX_FIFO(x)		(((x) & 0x7f) << 0)
+#define RDA_UART_RX_FIFO_MASK		(0x7f << 0)
+#define RDA_UART_TX_FIFO(x)		(((x) & 0x1f) << 8)
+#define RDA_UART_TX_FIFO_MASK		(0x1f << 8)
+#define RDA_UART_TX_ACTIVE		BIT(14)
+#define RDA_UART_RX_ACTIVE		BIT(15)
+#define RDA_UART_RX_OVERFLOW_ERR	BIT(16)
+#define RDA_UART_TX_OVERFLOW_ERR	BIT(17)
+#define RDA_UART_RX_PARITY_ERR		BIT(18)
+#define RDA_UART_RX_FRAMING_ERR		BIT(19)
+#define RDA_UART_RX_BREAK_INT		BIT(20)
+#define RDA_UART_DCTS			BIT(24)
+#define RDA_UART_CTS			BIT(25)
+#define RDA_UART_DTR			BIT(28)
+#define RDA_UART_CLK_ENABLED		BIT(31)
+
+/* UART_RXTX_BUFFER Bits */
+#define RDA_UART_RX_DATA(x)		(((x) & 0xff) << 0)
+#define RDA_UART_TX_DATA(x)		(((x) & 0xff) << 0)
+
+/* UART_IRQ_MASK Bits */
+#define RDA_UART_TX_MODEM_STATUS	BIT(0)
+#define RDA_UART_RX_DATA_AVAILABLE	BIT(1)
+#define RDA_UART_TX_DATA_NEEDED		BIT(2)
+#define RDA_UART_RX_TIMEOUT		BIT(3)
+#define RDA_UART_RX_LINE_ERR		BIT(4)
+#define RDA_UART_TX_DMA_DONE		BIT(5)
+#define RDA_UART_RX_DMA_DONE		BIT(6)
+#define RDA_UART_RX_DMA_TIMEOUT		BIT(7)
+#define RDA_UART_DTR_RISE		BIT(8)
+#define RDA_UART_DTR_FALL		BIT(9)
+
+/* UART_IRQ_CAUSE Bits */
+#define RDA_UART_TX_MODEM_STATUS_U	BIT(16)
+#define RDA_UART_RX_DATA_AVAILABLE_U	BIT(17)
+#define RDA_UART_TX_DATA_NEEDED_U	BIT(18)
+#define RDA_UART_RX_TIMEOUT_U		BIT(19)
+#define RDA_UART_RX_LINE_ERR_U		BIT(20)
+#define RDA_UART_TX_DMA_DONE_U		BIT(21)
+#define RDA_UART_RX_DMA_DONE_U		BIT(22)
+#define RDA_UART_RX_DMA_TIMEOUT_U	BIT(23)
+#define RDA_UART_DTR_RISE_U		BIT(24)
+#define RDA_UART_DTR_FALL_U		BIT(25)
+
+/* UART_TRIGGERS Bits */
+#define RDA_UART_RX_TRIGGER(x)		(((x) & 0x1f) << 0)
+#define RDA_UART_TX_TRIGGER(x)		(((x) & 0xf) << 8)
+#define RDA_UART_AFC_LEVEL(x)		(((x) & 0x1f) << 16)
+
+/* UART_CMD_SET Bits */
+#define RDA_UART_RI			BIT(0)
+#define RDA_UART_DCD			BIT(1)
+#define RDA_UART_DSR			BIT(2)
+#define RDA_UART_TX_BREAK_CONTROL	BIT(3)
+#define RDA_UART_TX_FINISH_N_WAIT	BIT(4)
+#define RDA_UART_RTS			BIT(5)
+#define RDA_UART_RX_FIFO_RESET		BIT(6)
+#define RDA_UART_TX_FIFO_RESET		BIT(7)
+
+#define RDA_UART_TX_FIFO_SIZE	16
+
+static struct uart_driver rda_uart_driver;
+
+struct rda_uart_port {
+	struct uart_port port;
+	struct clk *clk;
+};
+
+#define to_rda_uart_port(port) container_of(port, struct rda_uart_port, port)
+
+static struct rda_uart_port *rda_uart_ports[RDA_UART_PORT_NUM];
+
+static inline void rda_uart_write(struct uart_port *port, u32 val,
+				  unsigned int off)
+{
+	writel(val, port->membase + off);
+}
+
+static inline u32 rda_uart_read(struct uart_port *port, unsigned int off)
+{
+	return readl(port->membase + off);
+}
+
+static unsigned int rda_uart_tx_empty(struct uart_port *port)
+{
+	unsigned long flags;
+	unsigned int ret;
+	u32 val;
+
+	uart_port_lock_irqsave(port, &flags);
+
+	val = rda_uart_read(port, RDA_UART_STATUS);
+	ret = (val & RDA_UART_TX_FIFO_MASK) ? TIOCSER_TEMT : 0;
+
+	uart_port_unlock_irqrestore(port, flags);
+
+	return ret;
+}
+
+static unsigned int rda_uart_get_mctrl(struct uart_port *port)
+{
+	unsigned int mctrl = 0;
+	u32 cmd_set, status;
+
+	cmd_set = rda_uart_read(port, RDA_UART_CMD_SET);
+	status = rda_uart_read(port, RDA_UART_STATUS);
+	if (cmd_set & RDA_UART_RTS)
+		mctrl |= TIOCM_RTS;
+	if (!(status & RDA_UART_CTS))
+		mctrl |= TIOCM_CTS;
+
+	return mctrl;
+}
+
+static void rda_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	u32 val;
+
+	if (mctrl & TIOCM_RTS) {
+		val = rda_uart_read(port, RDA_UART_CMD_SET);
+		rda_uart_write(port, (val | RDA_UART_RTS), RDA_UART_CMD_SET);
+	} else {
+		/* Clear RTS to stop to receive. */
+		val = rda_uart_read(port, RDA_UART_CMD_CLR);
+		rda_uart_write(port, (val | RDA_UART_RTS), RDA_UART_CMD_CLR);
+	}
+
+	val = rda_uart_read(port, RDA_UART_CTRL);
+
+	if (mctrl & TIOCM_LOOP)
+		val |= RDA_UART_LOOP_BACK_EN;
+	else
+		val &= ~RDA_UART_LOOP_BACK_EN;
+
+	rda_uart_write(port, val, RDA_UART_CTRL);
+}
+
+static void rda_uart_stop_tx(struct uart_port *port)
+{
+	u32 val;
+
+	val = rda_uart_read(port, RDA_UART_IRQ_MASK);
+	val &= ~RDA_UART_TX_DATA_NEEDED;
+	rda_uart_write(port, val, RDA_UART_IRQ_MASK);
+
+	val = rda_uart_read(port, RDA_UART_CMD_SET);
+	val |= RDA_UART_TX_FIFO_RESET;
+	rda_uart_write(port, val, RDA_UART_CMD_SET);
+}
+
+static void rda_uart_stop_rx(struct uart_port *port)
+{
+	u32 val;
+
+	val = rda_uart_read(port, RDA_UART_IRQ_MASK);
+	val &= ~(RDA_UART_RX_DATA_AVAILABLE | RDA_UART_RX_TIMEOUT);
+	rda_uart_write(port, val, RDA_UART_IRQ_MASK);
+
+	/* Read Rx buffer before reset to avoid Rx timeout interrupt */
+	val = rda_uart_read(port, RDA_UART_RXTX_BUFFER);
+
+	val = rda_uart_read(port, RDA_UART_CMD_SET);
+	val |= RDA_UART_RX_FIFO_RESET;
+	rda_uart_write(port, val, RDA_UART_CMD_SET);
+}
+
+static void rda_uart_start_tx(struct uart_port *port)
+{
+	u32 val;
+
+	if (uart_tx_stopped(port)) {
+		rda_uart_stop_tx(port);
+		return;
+	}
+
+	val = rda_uart_read(port, RDA_UART_IRQ_MASK);
+	val |= RDA_UART_TX_DATA_NEEDED;
+	rda_uart_write(port, val, RDA_UART_IRQ_MASK);
+}
+
+static void rda_uart_change_baudrate(struct rda_uart_port *rda_port,
+				     unsigned long baud)
+{
+	clk_set_rate(rda_port->clk, baud * 8);
+}
+
+static void rda_uart_set_termios(struct uart_port *port,
+				 struct ktermios *termios,
+				 const struct ktermios *old)
+{
+	struct rda_uart_port *rda_port = to_rda_uart_port(port);
+	unsigned long flags;
+	unsigned int ctrl, cmd_set, cmd_clr, triggers;
+	unsigned int baud;
+	u32 irq_mask;
+
+	uart_port_lock_irqsave(port, &flags);
+
+	baud = uart_get_baud_rate(port, termios, old, 9600, port->uartclk / 4);
+	rda_uart_change_baudrate(rda_port, baud);
+
+	ctrl = rda_uart_read(port, RDA_UART_CTRL);
+	cmd_set = rda_uart_read(port, RDA_UART_CMD_SET);
+	cmd_clr = rda_uart_read(port, RDA_UART_CMD_CLR);
+
+	switch (termios->c_cflag & CSIZE) {
+	case CS5:
+	case CS6:
+		dev_warn(port->dev, "bit size not supported, using 7 bits\n");
+		fallthrough;
+	case CS7:
+		ctrl &= ~RDA_UART_DBITS_8;
+		termios->c_cflag &= ~CSIZE;
+		termios->c_cflag |= CS7;
+		break;
+	default:
+		ctrl |= RDA_UART_DBITS_8;
+		break;
+	}
+
+	/* stop bits */
+	if (termios->c_cflag & CSTOPB)
+		ctrl |= RDA_UART_TX_SBITS_2;
+	else
+		ctrl &= ~RDA_UART_TX_SBITS_2;
+
+	/* parity check */
+	if (termios->c_cflag & PARENB) {
+		ctrl |= RDA_UART_PARITY_EN;
+
+		/* Mark or Space parity */
+		if (termios->c_cflag & CMSPAR) {
+			if (termios->c_cflag & PARODD)
+				ctrl |= RDA_UART_PARITY_MARK;
+			else
+				ctrl |= RDA_UART_PARITY_SPACE;
+		} else if (termios->c_cflag & PARODD) {
+			ctrl |= RDA_UART_PARITY_ODD;
+		} else {
+			ctrl |= RDA_UART_PARITY_EVEN;
+		}
+	} else {
+		ctrl &= ~RDA_UART_PARITY_EN;
+	}
+
+	/* Hardware handshake (RTS/CTS) */
+	if (termios->c_cflag & CRTSCTS) {
+		ctrl   |= RDA_UART_FLOW_CNT_EN;
+		cmd_set |= RDA_UART_RTS;
+	} else {
+		ctrl   &= ~RDA_UART_FLOW_CNT_EN;
+		cmd_clr |= RDA_UART_RTS;
+	}
+
+	ctrl |= RDA_UART_ENABLE;
+	ctrl &= ~RDA_UART_DMA_EN;
+
+	triggers  = (RDA_UART_AFC_LEVEL(20) | RDA_UART_RX_TRIGGER(16));
+	irq_mask = rda_uart_read(port, RDA_UART_IRQ_MASK);
+	rda_uart_write(port, 0, RDA_UART_IRQ_MASK);
+
+	rda_uart_write(port, triggers, RDA_UART_IRQ_TRIGGERS);
+	rda_uart_write(port, ctrl, RDA_UART_CTRL);
+	rda_uart_write(port, cmd_set, RDA_UART_CMD_SET);
+	rda_uart_write(port, cmd_clr, RDA_UART_CMD_CLR);
+
+	rda_uart_write(port, irq_mask, RDA_UART_IRQ_MASK);
+
+	/* Don't rewrite B0 */
+	if (tty_termios_baud_rate(termios))
+		tty_termios_encode_baud_rate(termios, baud, baud);
+
+	/* update the per-port timeout */
+	uart_update_timeout(port, termios->c_cflag, baud);
+
+	uart_port_unlock_irqrestore(port, flags);
+}
+
+static void rda_uart_send_chars(struct uart_port *port)
+{
+	struct tty_port *tport = &port->state->port;
+	unsigned char ch;
+	u32 val;
+
+	if (uart_tx_stopped(port))
+		return;
+
+	if (port->x_char) {
+		while (!(rda_uart_read(port, RDA_UART_STATUS) &
+			 RDA_UART_TX_FIFO_MASK))
+			cpu_relax();
+
+		rda_uart_write(port, port->x_char, RDA_UART_RXTX_BUFFER);
+		port->icount.tx++;
+		port->x_char = 0;
+	}
+
+	while ((rda_uart_read(port, RDA_UART_STATUS) & RDA_UART_TX_FIFO_MASK) &&
+			uart_fifo_get(port, &ch))
+		rda_uart_write(port, ch, RDA_UART_RXTX_BUFFER);
+
+	if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+
+	if (!kfifo_is_empty(&tport->xmit_fifo)) {
+		/* Re-enable Tx FIFO interrupt */
+		val = rda_uart_read(port, RDA_UART_IRQ_MASK);
+		val |= RDA_UART_TX_DATA_NEEDED;
+		rda_uart_write(port, val, RDA_UART_IRQ_MASK);
+	}
+}
+
+static void rda_uart_receive_chars(struct uart_port *port)
+{
+	u32 status, val;
+
+	status = rda_uart_read(port, RDA_UART_STATUS);
+	while ((status & RDA_UART_RX_FIFO_MASK)) {
+		char flag = TTY_NORMAL;
+
+		if (status & RDA_UART_RX_PARITY_ERR) {
+			port->icount.parity++;
+			flag = TTY_PARITY;
+		}
+
+		if (status & RDA_UART_RX_FRAMING_ERR) {
+			port->icount.frame++;
+			flag = TTY_FRAME;
+		}
+
+		if (status & RDA_UART_RX_OVERFLOW_ERR) {
+			port->icount.overrun++;
+			flag = TTY_OVERRUN;
+		}
+
+		val = rda_uart_read(port, RDA_UART_RXTX_BUFFER);
+		val &= 0xff;
+
+		port->icount.rx++;
+		if (!uart_prepare_sysrq_char(port, val))
+			tty_insert_flip_char(&port->state->port, val, flag);
+
+		status = rda_uart_read(port, RDA_UART_STATUS);
+	}
+
+	tty_flip_buffer_push(&port->state->port);
+}
+
+static irqreturn_t rda_interrupt(int irq, void *dev_id)
+{
+	struct uart_port *port = dev_id;
+	u32 val, irq_mask;
+
+	uart_port_lock(port);
+
+	/* Clear IRQ cause */
+	val = rda_uart_read(port, RDA_UART_IRQ_CAUSE);
+	rda_uart_write(port, val, RDA_UART_IRQ_CAUSE);
+
+	if (val & (RDA_UART_RX_DATA_AVAILABLE | RDA_UART_RX_TIMEOUT))
+		rda_uart_receive_chars(port);
+
+	if (val & (RDA_UART_TX_DATA_NEEDED)) {
+		irq_mask = rda_uart_read(port, RDA_UART_IRQ_MASK);
+		irq_mask &= ~RDA_UART_TX_DATA_NEEDED;
+		rda_uart_write(port, irq_mask, RDA_UART_IRQ_MASK);
+
+		rda_uart_send_chars(port);
+	}
+
+	uart_unlock_and_check_sysrq(port);
+
+	return IRQ_HANDLED;
+}
+
+static int rda_uart_startup(struct uart_port *port)
+{
+	unsigned long flags;
+	int ret;
+	u32 val;
+
+	uart_port_lock_irqsave(port, &flags);
+	rda_uart_write(port, 0, RDA_UART_IRQ_MASK);
+	uart_port_unlock_irqrestore(port, flags);
+
+	ret = request_irq(port->irq, rda_interrupt, IRQF_NO_SUSPEND,
+			  "rda-uart", port);
+	if (ret)
+		return ret;
+
+	uart_port_lock_irqsave(port, &flags);
+
+	val = rda_uart_read(port, RDA_UART_CTRL);
+	val |= RDA_UART_ENABLE;
+	rda_uart_write(port, val, RDA_UART_CTRL);
+
+	/* enable rx interrupt */
+	val = rda_uart_read(port, RDA_UART_IRQ_MASK);
+	val |= (RDA_UART_RX_DATA_AVAILABLE | RDA_UART_RX_TIMEOUT);
+	rda_uart_write(port, val, RDA_UART_IRQ_MASK);
+
+	uart_port_unlock_irqrestore(port, flags);
+
+	return 0;
+}
+
+static void rda_uart_shutdown(struct uart_port *port)
+{
+	unsigned long flags;
+	u32 val;
+
+	uart_port_lock_irqsave(port, &flags);
+
+	rda_uart_stop_tx(port);
+	rda_uart_stop_rx(port);
+
+	val = rda_uart_read(port, RDA_UART_CTRL);
+	val &= ~RDA_UART_ENABLE;
+	rda_uart_write(port, val, RDA_UART_CTRL);
+
+	uart_port_unlock_irqrestore(port, flags);
+}
+
+static const char *rda_uart_type(struct uart_port *port)
+{
+	return (port->type == PORT_RDA) ? "rda-uart" : NULL;
+}
+
+static int rda_uart_request_port(struct uart_port *port)
+{
+	struct platform_device *pdev = to_platform_device(port->dev);
+	struct resource *res;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENXIO;
+
+	if (!devm_request_mem_region(port->dev, port->mapbase,
+				     resource_size(res), dev_name(port->dev)))
+		return -EBUSY;
+
+	if (port->flags & UPF_IOREMAP) {
+		port->membase = devm_ioremap(port->dev, port->mapbase,
+						     resource_size(res));
+		if (!port->membase)
+			return -EBUSY;
+	}
+
+	return 0;
+}
+
+static void rda_uart_config_port(struct uart_port *port, int flags)
+{
+	unsigned long irq_flags;
+
+	if (flags & UART_CONFIG_TYPE) {
+		port->type = PORT_RDA;
+		rda_uart_request_port(port);
+	}
+
+	uart_port_lock_irqsave(port, &irq_flags);
+
+	/* Clear mask, so no surprise interrupts. */
+	rda_uart_write(port, 0, RDA_UART_IRQ_MASK);
+
+	/* Clear status register */
+	rda_uart_write(port, 0, RDA_UART_STATUS);
+
+	uart_port_unlock_irqrestore(port, irq_flags);
+}
+
+static void rda_uart_release_port(struct uart_port *port)
+{
+	struct platform_device *pdev = to_platform_device(port->dev);
+	struct resource *res;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return;
+
+	if (port->flags & UPF_IOREMAP) {
+		devm_release_mem_region(port->dev, port->mapbase,
+					resource_size(res));
+		devm_iounmap(port->dev, port->membase);
+		port->membase = NULL;
+	}
+}
+
+static int rda_uart_verify_port(struct uart_port *port,
+				struct serial_struct *ser)
+{
+	if (port->type != PORT_RDA)
+		return -EINVAL;
+
+	if (port->irq != ser->irq)
+		return -EINVAL;
+
+	return 0;
+}
+
+static const struct uart_ops rda_uart_ops = {
+	.tx_empty       = rda_uart_tx_empty,
+	.get_mctrl      = rda_uart_get_mctrl,
+	.set_mctrl      = rda_uart_set_mctrl,
+	.start_tx       = rda_uart_start_tx,
+	.stop_tx        = rda_uart_stop_tx,
+	.stop_rx        = rda_uart_stop_rx,
+	.startup        = rda_uart_startup,
+	.shutdown       = rda_uart_shutdown,
+	.set_termios    = rda_uart_set_termios,
+	.type           = rda_uart_type,
+	.request_port	= rda_uart_request_port,
+	.release_port	= rda_uart_release_port,
+	.config_port	= rda_uart_config_port,
+	.verify_port	= rda_uart_verify_port,
+};
+
+#ifdef CONFIG_SERIAL_RDA_CONSOLE
+
+static void rda_console_putchar(struct uart_port *port, unsigned char ch)
+{
+	if (!port->membase)
+		return;
+
+	while (!(rda_uart_read(port, RDA_UART_STATUS) & RDA_UART_TX_FIFO_MASK))
+		cpu_relax();
+
+	rda_uart_write(port, ch, RDA_UART_RXTX_BUFFER);
+}
+
+static void rda_uart_port_write(struct uart_port *port, const char *s,
+				u_int count)
+{
+	u32 old_irq_mask;
+	unsigned long flags;
+	int locked = 1;
+
+	if (oops_in_progress)
+		locked = uart_port_trylock_irqsave(port, &flags);
+	else
+		uart_port_lock_irqsave(port, &flags);
+
+	old_irq_mask = rda_uart_read(port, RDA_UART_IRQ_MASK);
+	rda_uart_write(port, 0, RDA_UART_IRQ_MASK);
+
+	uart_console_write(port, s, count, rda_console_putchar);
+
+	/* wait until all contents have been sent out */
+	while (!(rda_uart_read(port, RDA_UART_STATUS) & RDA_UART_TX_FIFO_MASK))
+		cpu_relax();
+
+	rda_uart_write(port, old_irq_mask, RDA_UART_IRQ_MASK);
+
+	if (locked)
+		uart_port_unlock_irqrestore(port, flags);
+}
+
+static void rda_uart_console_write(struct console *co, const char *s,
+				   u_int count)
+{
+	struct rda_uart_port *rda_port;
+
+	rda_port = rda_uart_ports[co->index];
+	if (!rda_port)
+		return;
+
+	rda_uart_port_write(&rda_port->port, s, count);
+}
+
+static int rda_uart_console_setup(struct console *co, char *options)
+{
+	struct rda_uart_port *rda_port;
+	int baud = 921600;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+
+	if (co->index < 0 || co->index >= RDA_UART_PORT_NUM)
+		return -EINVAL;
+
+	rda_port = rda_uart_ports[co->index];
+	if (!rda_port || !rda_port->port.membase)
+		return -ENODEV;
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+	return uart_set_options(&rda_port->port, co, baud, parity, bits, flow);
+}
+
+static struct console rda_uart_console = {
+	.name = RDA_UART_DEV_NAME,
+	.write = rda_uart_console_write,
+	.device = uart_console_device,
+	.setup = rda_uart_console_setup,
+	.flags = CON_PRINTBUFFER,
+	.index = -1,
+	.data = &rda_uart_driver,
+};
+
+static int __init rda_uart_console_init(void)
+{
+	register_console(&rda_uart_console);
+
+	return 0;
+}
+console_initcall(rda_uart_console_init);
+
+static void rda_uart_early_console_write(struct console *co,
+					 const char *s,
+					 u_int count)
+{
+	struct earlycon_device *dev = co->data;
+
+	rda_uart_port_write(&dev->port, s, count);
+}
+
+static int __init
+rda_uart_early_console_setup(struct earlycon_device *device, const char *opt)
+{
+	if (!device->port.membase)
+		return -ENODEV;
+
+	device->con->write = rda_uart_early_console_write;
+
+	return 0;
+}
+
+OF_EARLYCON_DECLARE(rda, "rda,8810pl-uart",
+		    rda_uart_early_console_setup);
+
+#define RDA_UART_CONSOLE (&rda_uart_console)
+#else
+#define RDA_UART_CONSOLE NULL
+#endif /* CONFIG_SERIAL_RDA_CONSOLE */
+
+static struct uart_driver rda_uart_driver = {
+	.owner = THIS_MODULE,
+	.driver_name = "rda-uart",
+	.dev_name = RDA_UART_DEV_NAME,
+	.nr = RDA_UART_PORT_NUM,
+	.cons = RDA_UART_CONSOLE,
+};
+
+static const struct of_device_id rda_uart_dt_matches[] = {
+	{ .compatible = "rda,8810pl-uart" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, rda_uart_dt_matches);
+
+static int rda_uart_probe(struct platform_device *pdev)
+{
+	struct resource *res_mem;
+	struct rda_uart_port *rda_port;
+	int ret, irq;
+
+	if (pdev->dev.of_node)
+		pdev->id = of_alias_get_id(pdev->dev.of_node, "serial");
+
+	if (pdev->id < 0 || pdev->id >= RDA_UART_PORT_NUM) {
+		dev_err(&pdev->dev, "id %d out of range\n", pdev->id);
+		return -EINVAL;
+	}
+
+	res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res_mem) {
+		dev_err(&pdev->dev, "could not get mem\n");
+		return -ENODEV;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	if (rda_uart_ports[pdev->id]) {
+		dev_err(&pdev->dev, "port %d already allocated\n", pdev->id);
+		return -EBUSY;
+	}
+
+	rda_port = devm_kzalloc(&pdev->dev, sizeof(*rda_port), GFP_KERNEL);
+	if (!rda_port)
+		return -ENOMEM;
+
+	rda_port->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(rda_port->clk)) {
+		dev_err(&pdev->dev, "could not get clk\n");
+		return PTR_ERR(rda_port->clk);
+	}
+
+	rda_port->port.dev = &pdev->dev;
+	rda_port->port.regshift = 0;
+	rda_port->port.line = pdev->id;
+	rda_port->port.type = PORT_RDA;
+	rda_port->port.iotype = UPIO_MEM;
+	rda_port->port.mapbase = res_mem->start;
+	rda_port->port.irq = irq;
+	rda_port->port.uartclk = clk_get_rate(rda_port->clk);
+	if (rda_port->port.uartclk == 0) {
+		dev_err(&pdev->dev, "clock rate is zero\n");
+		return -EINVAL;
+	}
+	rda_port->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP |
+			       UPF_LOW_LATENCY;
+	rda_port->port.x_char = 0;
+	rda_port->port.fifosize = RDA_UART_TX_FIFO_SIZE;
+	rda_port->port.ops = &rda_uart_ops;
+
+	rda_uart_ports[pdev->id] = rda_port;
+	platform_set_drvdata(pdev, rda_port);
+
+	ret = uart_add_one_port(&rda_uart_driver, &rda_port->port);
+	if (ret)
+		rda_uart_ports[pdev->id] = NULL;
+
+	return ret;
+}
+
+static void rda_uart_remove(struct platform_device *pdev)
+{
+	struct rda_uart_port *rda_port = platform_get_drvdata(pdev);
+
+	uart_remove_one_port(&rda_uart_driver, &rda_port->port);
+	rda_uart_ports[pdev->id] = NULL;
+}
+
+static struct platform_driver rda_uart_platform_driver = {
+	.probe = rda_uart_probe,
+	.remove = rda_uart_remove,
+	.driver = {
+		.name = "rda-uart",
+		.of_match_table = rda_uart_dt_matches,
+	},
+};
+
+static int __init rda_uart_init(void)
+{
+	int ret;
+
+	ret = uart_register_driver(&rda_uart_driver);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&rda_uart_platform_driver);
+	if (ret)
+		uart_unregister_driver(&rda_uart_driver);
+
+	return ret;
+}
+
+static void __exit rda_uart_exit(void)
+{
+	platform_driver_unregister(&rda_uart_platform_driver);
+	uart_unregister_driver(&rda_uart_driver);
+}
+
+module_init(rda_uart_init);
+module_exit(rda_uart_exit);
+
+MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
+MODULE_DESCRIPTION("RDA8810PL serial device driver");
+MODULE_LICENSE("GPL");