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

[PATCH 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 TX/RX irq

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

 drivers/tty/serial/mps2-uart.c | 136 ++++++++++++++++++++++++++++-------------
 1 file changed, 95 insertions(+), 41 deletions(-)

-- 
2.7.4


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[PATCH 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.

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
---
 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 2/2] serial: mps2-uart: support combined tx and rx irq

[Vladimir Murzin]

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

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
---
 drivers/tty/serial/mps2-uart.c | 89 ++++++++++++++++++++++++++++++------------
 1 file changed, 64 insertions(+), 25 deletions(-)

diff --git a/drivers/tty/serial/mps2-uart.c b/drivers/tty/serial/mps2-uart.c
index 6da0633..e5fe764 100644
--- a/drivers/tty/serial/mps2-uart.c
+++ b/drivers/tty/serial/mps2-uart.c
@@ -66,11 +66,17 @@
 
 #define MPS2_MAX_PORTS		3
 
+#define UART_PORT_COMBINED_IRQS	BIT(0)
+
 struct mps2_uart_port {
 	struct uart_port port;
 	struct clk *clk;
-	unsigned int tx_irq;
+	union {
+		unsigned int combined_irq;
+		unsigned int tx_irq;
+	};
 	unsigned int rx_irq;
+	unsigned int flags;
 };
 
 static inline struct mps2_uart_port *to_mps2_port(struct uart_port *port)
@@ -232,6 +238,17 @@ static irqreturn_t mps2_uart_txirq(int irq, void *data)
 	return IRQ_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;
+
+	return IRQ_NONE;
+}
+
 static irqreturn_t mps2_uart_oerrirq(int irq, void *data)
 {
 	irqreturn_t handled = IRQ_NONE;
@@ -275,26 +292,35 @@ 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;
-	}
-
-	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;
-	}
-
 	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);
-		goto err_free_txirq;
+		return ret;
+	}
+
+	if (mps_port->flags & UART_PORT_COMBINED_IRQS) {
+		ret = request_irq(mps_port->combined_irq, mps2_uart_combinedirq, 0,
+				  MAKE_NAME(-combined), mps_port);
+		if (ret) {
+			dev_err(port->dev, "failed to register combinedirq (%d)\n", ret);
+			goto err_free_oerrirq;
+		}
+	} else {
+		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;
+		}
 	}
 
 	control |= UARTn_CTRL_RX_GRP | UARTn_CTRL_TX_GRP;
@@ -303,10 +329,10 @@ 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 +346,13 @@ 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_IRQS) {
+		free_irq(mps_port->combined_irq, mps_port);
+	} else {
+		free_irq(mps_port->rx_irq, mps_port);
+		free_irq(mps_port->tx_irq, mps_port);
+	}
+
 	free_irq(port->irq, mps_port);
 }
 
@@ -511,6 +542,9 @@ static int mps2_of_get_port(struct platform_device *pdev,
 	if (id < 0)
 		return id;
 
+	if (of_property_read_bool(np, "arm,mps2-combined-irq-only"))
+		mps_port->flags |= UART_PORT_COMBINED_IRQS;
+
 	mps_port->port.line = id;
 
 	return 0;
@@ -529,11 +563,6 @@ 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 +581,16 @@ static int mps2_init_port(struct platform_device *pdev,
 
 	clk_disable_unprepare(mps_port->clk);
 
+
+	if (mps_port->flags & UART_PORT_COMBINED_IRQS) {
+		mps_port->combined_irq = platform_get_irq(pdev, 0);
+		mps_port->port.irq = platform_get_irq(pdev, 1);
+	} 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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Re: [PATCH 1/2] serial: mps2-uart: move to dynamic port allocation

[Greg KH]

On Fri, Jan 25, 2019 at 02:13:16PM +0000, Vladimir Murzin wrote:
> 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.
> 
> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
> ---
>  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);

You forgot to call idr_destroy() when your code unloads :(

Yeah, it's not an obvious design pattern, I think someone will fix it up
someday...

thanks,

greg k-h

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

[Vladimir Murzin]

On 1/30/19 8:27 AM, Greg KH wrote:
> On Fri, Jan 25, 2019 at 02:13:16PM +0000, Vladimir Murzin wrote:
>> 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.
>>
>> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
>> ---
>>  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);
> 
> You forgot to call idr_destroy() when your code unloads :(

Hmm, but code doesn't unload since ce87122911f8 ("serial: mps2-uart: make driver explicitly non-modular")
or I'm missing something?

Cheers
Vladimir

> 
> Yeah, it's not an obvious design pattern, I think someone will fix it up
> someday...
> 
> thanks,
> 
> greg k-h
> 


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Re: [PATCH 2/2] serial: mps2-uart: support combined tx and rx irq

[Vladimir Murzin]

On 1/25/19 2:13 PM, Vladimir Murzin wrote:
> It turns out that some designs went for implementing only combined tx
> and rx interrupt, which is currently not supported by the driver.
> Support of combined irq is built on top of existent irq handlers and
> activated by the hint form device tree.
> 

It seems that folks combine rx, tx and overrun interrupts, so I'll send v2

Cheers
Vladimir

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

[Greg KH]

On Wed, Jan 30, 2019 at 08:58:53AM +0000, Vladimir Murzin wrote:
> On 1/30/19 8:27 AM, Greg KH wrote:
> > On Fri, Jan 25, 2019 at 02:13:16PM +0000, Vladimir Murzin wrote:
> >> 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.
> >>
> >> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
> >> ---
> >>  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);
> > 
> > You forgot to call idr_destroy() when your code unloads :(
> 
> Hmm, but code doesn't unload since ce87122911f8 ("serial: mps2-uart: make driver explicitly non-modular")
> or I'm missing something?

Ugh, ok, nevermind, I missed that, sorry.

greg k-h

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

[Vladimir Murzin]

On 1/30/19 9:24 AM, Greg KH wrote:
> On Wed, Jan 30, 2019 at 08:58:53AM +0000, Vladimir Murzin wrote:
>> On 1/30/19 8:27 AM, Greg KH wrote:
>>> On Fri, Jan 25, 2019 at 02:13:16PM +0000, Vladimir Murzin wrote:
>>>> 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.
>>>>
>>>> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
>>>> ---
>>>>  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);
>>>
>>> You forgot to call idr_destroy() when your code unloads :(
>>
>> Hmm, but code doesn't unload since ce87122911f8 ("serial: mps2-uart: make driver explicitly non-modular")
>> or I'm missing something?
> 
> Ugh, ok, nevermind, I missed that, sorry.

No problem, I'll add a note about that in commit message ;)

Thanks
Vladimir

> 
> greg k-h
> 
> _______________________________________________
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> 


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