[PATCH v2 0/2] serial: mps2-uart: minor improvements

[PATCH v2 0/2] serial: mps2-uart: minor improvements

[Vladimir Murzin]

This mini series is supposed to improve MPS2 uart driver for:
 1. platforms with number of virtual serial ports, like MPS3
 2. platforms with combined irq

Vladimir Murzin (2):
  serial: mps2-uart: move to dynamic port allocation
  serial: mps2-uart: support combined irq

 drivers/tty/serial/mps2-uart.c | 138 ++++++++++++++++++++++++++++-------------
 1 file changed, 96 insertions(+), 42 deletions(-)

-- 
2.7.4


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[PATCH v2 1/2] serial: mps2-uart: move to dynamic port allocation

[Vladimir Murzin]

Some designs, like MPS3, expose number of virtual serial ports which
already close or exceeds MPS2_MAX_PORTS. Increasing MPS2_MAX_PORTS
would have negative impact (in terms of memory consumption) on tiny
MPS2 platform which, in fact, has only one physically populated UART.

Start with converting existent static port array to idr. As a bonus it
make driver not to fail in case when no alias was specified in device
tree.

Note: there is no need in idr_destroy() because code doesn't unload
since ce87122911f8 ("serial: mps2-uart: make driver explicitly non-modular")

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
---
Changelog
	v1 -> v2
	   -  added a note about idr_destroy()

 drivers/tty/serial/mps2-uart.c | 47 ++++++++++++++++++++++++++++--------------
 1 file changed, 31 insertions(+), 16 deletions(-)

diff --git a/drivers/tty/serial/mps2-uart.c b/drivers/tty/serial/mps2-uart.c
index 9f8f637..6da0633 100644
--- a/drivers/tty/serial/mps2-uart.c
+++ b/drivers/tty/serial/mps2-uart.c
@@ -22,6 +22,7 @@
 #include <linux/serial_core.h>
 #include <linux/tty_flip.h>
 #include <linux/types.h>
+#include <linux/idr.h>
 
 #define SERIAL_NAME	"ttyMPS"
 #define DRIVER_NAME	"mps2-uart"
@@ -397,7 +398,7 @@ static const struct uart_ops mps2_uart_pops = {
 	.verify_port = mps2_uart_verify_port,
 };
 
-static struct mps2_uart_port mps2_uart_ports[MPS2_MAX_PORTS];
+static DEFINE_IDR(ports_idr);
 
 #ifdef CONFIG_SERIAL_MPS2_UART_CONSOLE
 static void mps2_uart_console_putchar(struct uart_port *port, int ch)
@@ -410,7 +411,8 @@ static void mps2_uart_console_putchar(struct uart_port *port, int ch)
 
 static void mps2_uart_console_write(struct console *co, const char *s, unsigned int cnt)
 {
-	struct uart_port *port = &mps2_uart_ports[co->index].port;
+	struct mps2_uart_port *mps_port = idr_find(&ports_idr, co->index);
+	struct uart_port *port = &mps_port->port;
 
 	uart_console_write(port, s, cnt, mps2_uart_console_putchar);
 }
@@ -426,7 +428,10 @@ static int mps2_uart_console_setup(struct console *co, char *options)
 	if (co->index < 0 || co->index >= MPS2_MAX_PORTS)
 		return -ENODEV;
 
-	mps_port = &mps2_uart_ports[co->index];
+	mps_port = idr_find(&ports_idr, co->index);
+
+	if (!mps_port)
+		return -ENODEV;
 
 	if (options)
 		uart_parse_options(options, &baud, &parity, &bits, &flow);
@@ -487,27 +492,32 @@ static struct uart_driver mps2_uart_driver = {
 	.cons = MPS2_SERIAL_CONSOLE,
 };
 
-static struct mps2_uart_port *mps2_of_get_port(struct platform_device *pdev)
+static int mps2_of_get_port(struct platform_device *pdev,
+			    struct mps2_uart_port *mps_port)
 {
 	struct device_node *np = pdev->dev.of_node;
 	int id;
 
 	if (!np)
-		return NULL;
+		return -ENODEV;
 
 	id = of_alias_get_id(np, "serial");
+
+	if (id < 0)
+		id = idr_alloc_cyclic(&ports_idr, (void *)mps_port, 0, MPS2_MAX_PORTS, GFP_KERNEL);
+	else
+		id = idr_alloc(&ports_idr, (void *)mps_port, id, MPS2_MAX_PORTS, GFP_KERNEL);
+
 	if (id < 0)
-		id = 0;
+		return id;
 
-	if (WARN_ON(id >= MPS2_MAX_PORTS))
-		return NULL;
+	mps_port->port.line = id;
 
-	mps2_uart_ports[id].port.line = id;
-	return &mps2_uart_ports[id];
+	return 0;
 }
 
-static int mps2_init_port(struct mps2_uart_port *mps_port,
-			  struct platform_device *pdev)
+static int mps2_init_port(struct platform_device *pdev,
+			  struct mps2_uart_port *mps_port)
 {
 	struct resource *res;
 	int ret;
@@ -550,11 +560,16 @@ static int mps2_serial_probe(struct platform_device *pdev)
 	struct mps2_uart_port *mps_port;
 	int ret;
 
-	mps_port = mps2_of_get_port(pdev);
-	if (!mps_port)
-		return -ENODEV;
+	mps_port = devm_kzalloc(&pdev->dev, sizeof(struct mps2_uart_port), GFP_KERNEL);
+
+        if (!mps_port)
+                return -ENOMEM;
+
+	ret = mps2_of_get_port(pdev, mps_port);
+	if (ret)
+		return ret;
 
-	ret = mps2_init_port(mps_port, pdev);
+	ret = mps2_init_port(pdev, mps_port);
 	if (ret)
 		return ret;
 
-- 
2.7.4


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[PATCH v2 2/2] serial: mps2-uart: support combined irq

[Vladimir Murzin]

It turns out that some designs went for implementing only combined
interrupt for rx, tx and overrun, which is currently not supported
by the driver.  Support of combined irq is built on top of existent
irq handlers and activated automatically if only single irq was
specified in device tree.

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
---
Changelog
	v1 -> v2
	   - overrun interrupt also combined with rx and tx
	   - count number of irqs provided via dt to detect
	     use of combined irq.

 drivers/tty/serial/mps2-uart.c | 91 ++++++++++++++++++++++++++++++------------
 1 file changed, 65 insertions(+), 26 deletions(-)

diff --git a/drivers/tty/serial/mps2-uart.c b/drivers/tty/serial/mps2-uart.c
index 6da0633..4404eb7 100644
--- a/drivers/tty/serial/mps2-uart.c
+++ b/drivers/tty/serial/mps2-uart.c
@@ -66,11 +66,14 @@
 
 #define MPS2_MAX_PORTS		3
 
+#define UART_PORT_COMBINED_IRQ	BIT(0)
+
 struct mps2_uart_port {
 	struct uart_port port;
 	struct clk *clk;
 	unsigned int tx_irq;
 	unsigned int rx_irq;
+	unsigned int flags;
 };
 
 static inline struct mps2_uart_port *to_mps2_port(struct uart_port *port)
@@ -265,6 +268,20 @@ static irqreturn_t mps2_uart_oerrirq(int irq, void *data)
 	return handled;
 }
 
+static irqreturn_t mps2_uart_combinedirq(int irq, void *data)
+{
+	if (mps2_uart_rxirq(irq, data) == IRQ_HANDLED)
+		return IRQ_HANDLED;
+
+	if (mps2_uart_txirq(irq, data) == IRQ_HANDLED)
+		return IRQ_HANDLED;
+
+	if (mps2_uart_oerrirq(irq, data) == IRQ_HANDLED)
+		return IRQ_HANDLED;
+
+	return IRQ_NONE;
+}
+
 static int mps2_uart_startup(struct uart_port *port)
 {
 	struct mps2_uart_port *mps_port = to_mps2_port(port);
@@ -275,26 +292,37 @@ static int mps2_uart_startup(struct uart_port *port)
 
 	mps2_uart_write8(port, control, UARTn_CTRL);
 
-	ret = request_irq(mps_port->rx_irq, mps2_uart_rxirq, 0,
-			  MAKE_NAME(-rx), mps_port);
-	if (ret) {
-		dev_err(port->dev, "failed to register rxirq (%d)\n", ret);
-		return ret;
-	}
+	if (mps_port->flags & UART_PORT_COMBINED_IRQ) {
+		ret = request_irq(port->irq, mps2_uart_combinedirq, 0,
+				  MAKE_NAME(-combined), mps_port);
 
-	ret = request_irq(mps_port->tx_irq, mps2_uart_txirq, 0,
-			  MAKE_NAME(-tx), mps_port);
-	if (ret) {
-		dev_err(port->dev, "failed to register txirq (%d)\n", ret);
-		goto err_free_rxirq;
-	}
+		if (ret) {
+			dev_err(port->dev, "failed to register combinedirq (%d)\n", ret);
+			return ret;
+		}
+	} else {
+		ret = request_irq(port->irq, mps2_uart_oerrirq, IRQF_SHARED,
+				  MAKE_NAME(-overrun), mps_port);
+
+		if (ret) {
+			dev_err(port->dev, "failed to register oerrirq (%d)\n", ret);
+			return ret;
+		}
 
-	ret = request_irq(port->irq, mps2_uart_oerrirq, IRQF_SHARED,
-			  MAKE_NAME(-overrun), mps_port);
+		ret = request_irq(mps_port->rx_irq, mps2_uart_rxirq, 0,
+				  MAKE_NAME(-rx), mps_port);
+		if (ret) {
+			dev_err(port->dev, "failed to register rxirq (%d)\n", ret);
+			goto err_free_oerrirq;
+		}
+
+		ret = request_irq(mps_port->tx_irq, mps2_uart_txirq, 0,
+				  MAKE_NAME(-tx), mps_port);
+		if (ret) {
+			dev_err(port->dev, "failed to register txirq (%d)\n", ret);
+			goto err_free_rxirq;
+		}
 
-	if (ret) {
-		dev_err(port->dev, "failed to register oerrirq (%d)\n", ret);
-		goto err_free_txirq;
 	}
 
 	control |= UARTn_CTRL_RX_GRP | UARTn_CTRL_TX_GRP;
@@ -303,10 +331,10 @@ static int mps2_uart_startup(struct uart_port *port)
 
 	return 0;
 
-err_free_txirq:
-	free_irq(mps_port->tx_irq, mps_port);
 err_free_rxirq:
 	free_irq(mps_port->rx_irq, mps_port);
+err_free_oerrirq:
+	free_irq(port->irq, mps_port);
 
 	return ret;
 }
@@ -320,8 +348,11 @@ static void mps2_uart_shutdown(struct uart_port *port)
 
 	mps2_uart_write8(port, control, UARTn_CTRL);
 
-	free_irq(mps_port->rx_irq, mps_port);
-	free_irq(mps_port->tx_irq, mps_port);
+	if (!mps_port->flags & UART_PORT_COMBINED_IRQ) {
+		free_irq(mps_port->rx_irq, mps_port);
+		free_irq(mps_port->tx_irq, mps_port);
+	}
+
 	free_irq(port->irq, mps_port);
 }
 
@@ -511,6 +542,10 @@ static int mps2_of_get_port(struct platform_device *pdev,
 	if (id < 0)
 		return id;
 
+	/* Only combined irq is presesnt */
+	if (platform_irq_count(pdev) == 1)
+		mps_port->flags |= UART_PORT_COMBINED_IRQ;
+
 	mps_port->port.line = id;
 
 	return 0;
@@ -529,11 +564,6 @@ static int mps2_init_port(struct platform_device *pdev,
 
 	mps_port->port.mapbase = res->start;
 	mps_port->port.mapsize = resource_size(res);
-
-	mps_port->rx_irq = platform_get_irq(pdev, 0);
-	mps_port->tx_irq = platform_get_irq(pdev, 1);
-	mps_port->port.irq = platform_get_irq(pdev, 2);
-
 	mps_port->port.iotype = UPIO_MEM;
 	mps_port->port.flags = UPF_BOOT_AUTOCONF;
 	mps_port->port.fifosize = 1;
@@ -552,6 +582,15 @@ static int mps2_init_port(struct platform_device *pdev,
 
 	clk_disable_unprepare(mps_port->clk);
 
+
+	if (mps_port->flags & UART_PORT_COMBINED_IRQ) {
+		mps_port->port.irq = platform_get_irq(pdev, 0);
+	} else {
+		mps_port->rx_irq = platform_get_irq(pdev, 0);
+		mps_port->tx_irq = platform_get_irq(pdev, 1);
+		mps_port->port.irq = platform_get_irq(pdev, 2);
+	}
+
 	return ret;
 }
 
-- 
2.7.4


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