[PATCHv2 0/5] serial: 8250: 8250_dw changes and dynamic capabilities

[PATCHv2 0/5] serial: 8250: 8250_dw changes and dynamic capabilities

[Heikki Krogerus]

Changes since v1:
- rebased on top of Greg's tty-next

These are mainly small 8250_dw.c changes. The interesting patch is
probable the first one that changes 8250.c so the drivers are able to
deliver their UART's capabilities when they are registering ports.


Heikki Krogerus (5):
  serial: 8250: Allow drivers to deliver capabilities
  serial: 8250_dw: Don't use UPF_FIXED_TYPE
  serial: 8250_dw: Map IO memory
  serial: 8250_dw: Move device tree code to separate function
  serial: 8250_dw: Set FIFO size dynamically

 drivers/tty/serial/8250/8250.c    |   22 ++++--
 drivers/tty/serial/8250/8250_dw.c |  140 +++++++++++++++++++++++++++----------
 2 files changed, 120 insertions(+), 42 deletions(-)

-- 
1.7.10.4

[PATCHv2 1/5] serial: 8250: Allow drivers to deliver capabilities

[Heikki Krogerus]

Modern UARTs are able to provide information about their
capabilities such as FIFO size. This allows the drivers to
deliver this information to 8250.c when they are registering
ports.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/tty/serial/8250/8250.c |   22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/serial/8250/8250.c b/drivers/tty/serial/8250/8250.c
index d085e3a..da3f828 100644
--- a/drivers/tty/serial/8250/8250.c
+++ b/drivers/tty/serial/8250/8250.c
@@ -1980,9 +1980,12 @@ static int serial8250_startup(struct uart_port *port)
 	if (port->type == PORT_8250_CIR)
 		return -ENODEV;
 
-	port->fifosize = uart_config[up->port.type].fifo_size;
-	up->tx_loadsz = uart_config[up->port.type].tx_loadsz;
-	up->capabilities = uart_config[up->port.type].flags;
+	if (!port->fifosize)
+		port->fifosize = uart_config[port->type].fifo_size;
+	if (!up->tx_loadsz)
+		up->tx_loadsz = uart_config[port->type].tx_loadsz;
+	if (!up->capabilities)
+		up->capabilities = uart_config[port->type].flags;
 	up->mcr = 0;
 
 	if (port->iotype != up->cur_iotype)
@@ -2815,9 +2818,12 @@ static void
 serial8250_init_fixed_type_port(struct uart_8250_port *up, unsigned int type)
 {
 	up->port.type = type;
-	up->port.fifosize = uart_config[type].fifo_size;
-	up->capabilities = uart_config[type].flags;
-	up->tx_loadsz = uart_config[type].tx_loadsz;
+	if (!up->port.fifosize)
+		up->port.fifosize = uart_config[type].fifo_size;
+	if (!up->tx_loadsz)
+		up->tx_loadsz = uart_config[type].tx_loadsz;
+	if (!up->capabilities)
+		up->capabilities = uart_config[type].flags;
 }
 
 static void __init
@@ -3251,6 +3257,10 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
 		uart->bugs		= up->bugs;
 		uart->port.mapbase      = up->port.mapbase;
 		uart->port.private_data = up->port.private_data;
+		uart->port.fifosize	= up->port.fifosize;
+		uart->tx_loadsz		= up->tx_loadsz;
+		uart->capabilities	= up->capabilities;
+
 		if (up->port.dev)
 			uart->port.dev = up->port.dev;
 
-- 
1.7.10.4

[PATCHv2 2/5] serial: 8250_dw: Don't use UPF_FIXED_TYPE

[Heikki Krogerus]

Allow 8250.c to determine the port type for us. This allows
the driver take advantage of FIFO on Designware UARTs that
have it.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/tty/serial/8250/8250_dw.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 1d0dba2..ff83ea5 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -112,7 +112,7 @@ static int dw8250_probe(struct platform_device *pdev)
 	uart.port.handle_irq = dw8250_handle_irq;
 	uart.port.type = PORT_8250;
 	uart.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP |
-		UPF_FIXED_PORT | UPF_FIXED_TYPE;
+		UPF_FIXED_PORT;
 	uart.port.dev = &pdev->dev;
 
 	uart.port.iotype = UPIO_MEM;
-- 
1.7.10.4

[PATCHv2 3/5] serial: 8250_dw: Map IO memory

[Heikki Krogerus]

This needs to be done in order to later access the
Designware specific registers.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/tty/serial/8250/8250_dw.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index ff83ea5..300bbed 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -111,10 +111,13 @@ static int dw8250_probe(struct platform_device *pdev)
 	uart.port.irq = irq->start;
 	uart.port.handle_irq = dw8250_handle_irq;
 	uart.port.type = PORT_8250;
-	uart.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP |
-		UPF_FIXED_PORT;
+	uart.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT;
 	uart.port.dev = &pdev->dev;
 
+	uart.port.membase = ioremap(regs->start, regs->end - regs->start);
+	if (!uart.port.membase)
+		return -ENOMEM;
+
 	uart.port.iotype = UPIO_MEM;
 	uart.port.serial_in = dw8250_serial_in;
 	uart.port.serial_out = dw8250_serial_out;
-- 
1.7.10.4

Re: [PATCHv2 3/5] serial: 8250_dw: Map IO memory

[Alan Cox]

On Mon,  3 Dec 2012 13:17:57 +0200
Heikki Krogerus <heikki.krogerus@linux.intel.com> wrote:

> This needs to be done in order to later access the
> Designware specific registers.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

Series Acked-by: Alan Cox <alan@linux.intel.com>

Re: [PATCHv2 3/5] serial: 8250_dw: Map IO memory

[Jamie Iles]

Hi Heikki,

On Mon, Dec 03, 2012 at 01:17:57PM +0200, Heikki Krogerus wrote:
> This needs to be done in order to later access the
> Designware specific registers.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
>  drivers/tty/serial/8250/8250_dw.c |    7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
> index ff83ea5..300bbed 100644
> --- a/drivers/tty/serial/8250/8250_dw.c
> +++ b/drivers/tty/serial/8250/8250_dw.c
> @@ -111,10 +111,13 @@ static int dw8250_probe(struct platform_device *pdev)
>  	uart.port.irq = irq->start;
>  	uart.port.handle_irq = dw8250_handle_irq;
>  	uart.port.type = PORT_8250;
> -	uart.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP |
> -		UPF_FIXED_PORT;
> +	uart.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT;
>  	uart.port.dev = &pdev->dev;
>  
> +	uart.port.membase = ioremap(regs->start, regs->end - regs->start);

Doesn't this have an off-by-one error?  Perhaps:

+	uart.port.membase = ioremap(regs->start, resource_size(regs));

instead?

Jamie

Re: [PATCHv2 3/5] serial: 8250_dw: Map IO memory

[Heikki Krogerus]

Hi Jamie,

On Mon, Dec 03, 2012 at 03:40:14PM +0000, Jamie Iles wrote:
> > +	uart.port.membase = ioremap(regs->start, regs->end - regs->start);
> 
> Doesn't this have an off-by-one error?

True.

> +	uart.port.membase = ioremap(regs->start, resource_size(regs));
> 
> instead?

Yes, I'll fix this. Thanks!

-- 
heikki

[PATCHv3 3/5] serial: 8250_dw: Map IO memory

[Heikki Krogerus]

This needs to be done in order to later access the
Designware specific registers.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/tty/serial/8250/8250_dw.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index ff83ea5..e174901 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -111,10 +111,13 @@ static int dw8250_probe(struct platform_device *pdev)
 	uart.port.irq = irq->start;
 	uart.port.handle_irq = dw8250_handle_irq;
 	uart.port.type = PORT_8250;
-	uart.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP |
-		UPF_FIXED_PORT;
+	uart.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT;
 	uart.port.dev = &pdev->dev;
 
+	uart.port.membase = ioremap(regs->start, resource_size(regs));
+	if (!uart.port.membase)
+		return -ENOMEM;
+
 	uart.port.iotype = UPIO_MEM;
 	uart.port.serial_in = dw8250_serial_in;
 	uart.port.serial_out = dw8250_serial_out;
-- 
1.7.10.4

Re: [PATCHv3 3/5] serial: 8250_dw: Map IO memory

[Jamie Iles]

Looks good to me!

On Tue, Dec 04, 2012 at 05:21:52PM +0200, Heikki Krogerus wrote:
> This needs to be done in order to later access the
> Designware specific registers.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

Reviewed-by: Jamie Iles <jamie@jamieiles.com>

[PATCHv2 4/5] serial: 8250_dw: Move device tree code to separate function

[Heikki Krogerus]

Trivial cleanup. This makes it easier to add different
methods to enumerate the device, for example ACPI 5.0
enumeration.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/tty/serial/8250/8250_dw.c |   76 ++++++++++++++++++++++---------------
 1 file changed, 46 insertions(+), 30 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 300bbed..c4e28df 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -87,25 +87,51 @@ static int dw8250_handle_irq(struct uart_port *p)
 	return 0;
 }
 
+static int dw8250_probe_of(struct uart_port *p)
+{
+	struct device_node	*np = p->dev->of_node;
+	u32			val;
+
+	if (!of_property_read_u32(np, "reg-io-width", &val)) {
+		switch (val) {
+		case 1:
+			break;
+		case 4:
+			p->iotype = UPIO_MEM32;
+			p->serial_in = dw8250_serial_in32;
+			p->serial_out = dw8250_serial_out32;
+			break;
+		default:
+			dev_err(p->dev, "unsupported reg-io-width (%u)\n", val);
+			return -EINVAL;
+		}
+	}
+
+	if (!of_property_read_u32(np, "reg-shift", &val))
+		p->regshift = val;
+
+	if (of_property_read_u32(np, "clock-frequency", &val)) {
+		dev_err(p->dev, "no clock-frequency property set\n");
+		return -EINVAL;
+	}
+	p->uartclk = val;
+
+	return 0;
+}
+
 static int dw8250_probe(struct platform_device *pdev)
 {
 	struct uart_8250_port uart = {};
 	struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
-	struct device_node *np = pdev->dev.of_node;
-	u32 val;
 	struct dw8250_data *data;
+	int err;
 
 	if (!regs || !irq) {
 		dev_err(&pdev->dev, "no registers/irq defined\n");
 		return -EINVAL;
 	}
 
-	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
-	if (!data)
-		return -ENOMEM;
-	uart.port.private_data = data;
-
 	spin_lock_init(&uart.port.lock);
 	uart.port.mapbase = regs->start;
 	uart.port.irq = irq->start;
@@ -121,30 +147,20 @@ static int dw8250_probe(struct platform_device *pdev)
 	uart.port.iotype = UPIO_MEM;
 	uart.port.serial_in = dw8250_serial_in;
 	uart.port.serial_out = dw8250_serial_out;
-	if (!of_property_read_u32(np, "reg-io-width", &val)) {
-		switch (val) {
-		case 1:
-			break;
-		case 4:
-			uart.port.iotype = UPIO_MEM32;
-			uart.port.serial_in = dw8250_serial_in32;
-			uart.port.serial_out = dw8250_serial_out32;
-			break;
-		default:
-			dev_err(&pdev->dev, "unsupported reg-io-width (%u)\n",
-				val);
-			return -EINVAL;
-		}
+
+	if (pdev->dev.of_node) {
+		err = dw8250_probe_of(&uart.port);
+		if (err)
+			return err;
+	} else {
+		return -ENODEV;
 	}
 
-	if (!of_property_read_u32(np, "reg-shift", &val))
-		uart.port.regshift = val;
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
 
-	if (of_property_read_u32(np, "clock-frequency", &val)) {
-		dev_err(&pdev->dev, "no clock-frequency property set\n");
-		return -EINVAL;
-	}
-	uart.port.uartclk = val;
+	uart.port.private_data = data;
 
 	data->line = serial8250_register_8250_port(&uart);
 	if (data->line < 0)
@@ -187,7 +203,7 @@ static int dw8250_resume(struct platform_device *pdev)
 #define dw8250_resume NULL
 #endif /* CONFIG_PM */
 
-static const struct of_device_id dw8250_match[] = {
+static const struct of_device_id dw8250_of_match[] = {
 	{ .compatible = "snps,dw-apb-uart" },
 	{ /* Sentinel */ }
 };
@@ -197,7 +213,7 @@ static struct platform_driver dw8250_platform_driver = {
 	.driver = {
 		.name		= "dw-apb-uart",
 		.owner		= THIS_MODULE,
-		.of_match_table	= dw8250_match,
+		.of_match_table	= dw8250_of_match,
 	},
 	.probe			= dw8250_probe,
 	.remove			= dw8250_remove,
-- 
1.7.10.4

[PATCHv2 5/5] serial: 8250_dw: Set FIFO size dynamically

[Heikki Krogerus]

Designware UART provides optional Component Parameter
Register that lists most of the capabilities of the UART,
including FIFO size. This uses that register to set FIFO
size for the port before registering it.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/tty/serial/8250/8250_dw.c |   57 ++++++++++++++++++++++++++++++++++---
 1 file changed, 53 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index c4e28df..e834d41 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -25,6 +25,28 @@
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 
+/* Offsets for the DesignWare specific registers */
+#define DW_UART_USR	0x1f /* UART Status Register */
+#define DW_UART_CPR	0xf4 /* Component Parameter Register */
+#define DW_UART_UCV	0xf8 /* UART Component Version */
+
+/* Component Parameter Register bits */
+#define DW_UART_CPR_ABP_DATA_WIDTH	(3 << 0)
+#define DW_UART_CPR_AFCE_MODE		(1 << 4)
+#define DW_UART_CPR_THRE_MODE		(1 << 5)
+#define DW_UART_CPR_SIR_MODE		(1 << 6)
+#define DW_UART_CPR_SIR_LP_MODE		(1 << 7)
+#define DW_UART_CPR_ADDITIONAL_FEATURES	(1 << 8)
+#define DW_UART_CPR_FIFO_ACCESS		(1 << 9)
+#define DW_UART_CPR_FIFO_STAT		(1 << 10)
+#define DW_UART_CPR_SHADOW		(1 << 11)
+#define DW_UART_CPR_ENCODED_PARMS	(1 << 12)
+#define DW_UART_CPR_DMA_EXTRA		(1 << 13)
+#define DW_UART_CPR_FIFO_MODE		(0xff << 16)
+/* Helper for fifo size calculation */
+#define DW_UART_CPR_FIFO_SIZE(a)	(((a >> 16) & 0xff) * 16)
+
+
 struct dw8250_data {
 	int	last_lcr;
 	int	line;
@@ -66,9 +88,6 @@ static unsigned int dw8250_serial_in32(struct uart_port *p, int offset)
 	return readl(p->membase + offset);
 }
 
-/* Offset for the DesignWare's UART Status Register. */
-#define UART_USR	0x1f
-
 static int dw8250_handle_irq(struct uart_port *p)
 {
 	struct dw8250_data *d = p->private_data;
@@ -78,7 +97,7 @@ static int dw8250_handle_irq(struct uart_port *p)
 		return 1;
 	} else if ((iir & UART_IIR_BUSY) == UART_IIR_BUSY) {
 		/* Clear the USR and write the LCR again. */
-		(void)p->serial_in(p, UART_USR);
+		(void)p->serial_in(p, DW_UART_USR);
 		p->serial_out(p, d->last_lcr, UART_LCR);
 
 		return 1;
@@ -119,6 +138,34 @@ static int dw8250_probe_of(struct uart_port *p)
 	return 0;
 }
 
+static void dw8250_setup_port(struct uart_8250_port *up)
+{
+	struct uart_port	*p = &up->port;
+	u32			reg = readl(p->membase + DW_UART_UCV);
+
+	/*
+	 * If the Component Version Register returns zero, we know that
+	 * ADDITIONAL_FEATURES are not enabled. No need to go any further.
+	 */
+	if (!reg)
+		return;
+
+	dev_dbg_ratelimited(p->dev, "Designware UART version %c.%c%c\n",
+		(reg >> 24) & 0xff, (reg >> 16) & 0xff, (reg >> 8) & 0xff);
+
+	reg = readl(p->membase + DW_UART_CPR);
+	if (!reg)
+		return;
+
+	/* Select the type based on fifo */
+	if (reg & DW_UART_CPR_FIFO_MODE) {
+		p->type = PORT_16550A;
+		p->flags |= UPF_FIXED_TYPE;
+		p->fifosize = DW_UART_CPR_FIFO_SIZE(reg);
+		up->tx_loadsz = p->fifosize;
+	}
+}
+
 static int dw8250_probe(struct platform_device *pdev)
 {
 	struct uart_8250_port uart = {};
@@ -156,6 +203,8 @@ static int dw8250_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
+	dw8250_setup_port(&uart);
+
 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
-- 
1.7.10.4

Re: [PATCHv2 0/5] serial: 8250: 8250_dw changes and dynamic capabilities

[Jamie Iles]

Hi Heikki,

On Mon, Dec 03, 2012 at 01:17:54PM +0200, Heikki Krogerus wrote:
> 
> Changes since v1:
> - rebased on top of Greg's tty-next
> 
> These are mainly small 8250_dw.c changes. The interesting patch is
> probable the first one that changes 8250.c so the drivers are able to
> deliver their UART's capabilities when they are registering ports.

Other than my comment on 3/5 it looks great.

Reviewed-by: Jamie Iles <jamie@jamieiles.com>

Jamie

Re: [PATCHv2 0/5] serial: 8250: 8250_dw changes and dynamic capabilities

[Heikki Krogerus]

Hi,

On Mon, Dec 03, 2012 at 01:17:54PM +0200, Heikki Krogerus wrote:
> Changes since v1:
> - rebased on top of Greg's tty-next
> 
> These are mainly small 8250_dw.c changes. The interesting patch is
> probable the first one that changes 8250.c so the drivers are able to
> deliver their UART's capabilities when they are registering ports.

I will make one more version of this set. I'll add ACPI support for
8250_dw.c, and also introduce dmaengine support for 8250.c.

-- 
heikki