Linux-Serial Archive on lore.kernel.org
 help / color / Atom feed
* [PATCH] serial: 8250_tegra: Create Tegra specific 8250 driver
@ 2020-01-20 16:01 Jon Hunter
  2020-01-21 15:41 ` Greg Kroah-Hartman
  2020-01-21 16:31 ` Dmitry Osipenko
  0 siblings, 2 replies; 7+ messages in thread
From: Jon Hunter @ 2020-01-20 16:01 UTC (permalink / raw)
  To: Greg Kroah-Hartman, Jiri Slaby, Thierry Reding
  Cc: linux-serial, linux-kernel, linux-tegra, Jeff Brasen, Jon Hunter

From: Jeff Brasen <jbrasen@nvidia.com>

To support booting NVIDIA Tegra platforms with either Device-Tree or
ACPI, create a Tegra specific 8250 serial driver that supports both
firmware types. Another benefit from doing this, is that the Tegra
specific codec in the generic Open Firmware 8250 driver can now be
removed.

Signed-off-by: Jeff Brasen <jbrasen@nvidia.com>
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
---
 drivers/tty/serial/8250/8250_of.c    |  28 ----
 drivers/tty/serial/8250/8250_tegra.c | 197 +++++++++++++++++++++++++++
 drivers/tty/serial/8250/Kconfig      |   9 ++
 drivers/tty/serial/8250/Makefile     |   1 +
 4 files changed, 207 insertions(+), 28 deletions(-)
 create mode 100644 drivers/tty/serial/8250/8250_tegra.c

diff --git a/drivers/tty/serial/8250/8250_of.c b/drivers/tty/serial/8250/8250_of.c
index 531ad67395e0..5e45cf8dbc6e 100644
--- a/drivers/tty/serial/8250/8250_of.c
+++ b/drivers/tty/serial/8250/8250_of.c
@@ -7,7 +7,6 @@
 #include <linux/console.h>
 #include <linux/module.h>
 #include <linux/slab.h>
-#include <linux/delay.h>
 #include <linux/serial_core.h>
 #include <linux/serial_reg.h>
 #include <linux/of_address.h>
@@ -26,28 +25,6 @@ struct of_serial_info {
 	int line;
 };
 
-#ifdef CONFIG_ARCH_TEGRA
-static void tegra_serial_handle_break(struct uart_port *p)
-{
-	unsigned int status, tmout = 10000;
-
-	do {
-		status = p->serial_in(p, UART_LSR);
-		if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
-			status = p->serial_in(p, UART_RX);
-		else
-			break;
-		if (--tmout == 0)
-			break;
-		udelay(1);
-	} while (1);
-}
-#else
-static inline void tegra_serial_handle_break(struct uart_port *port)
-{
-}
-#endif
-
 static int of_8250_rs485_config(struct uart_port *port,
 				  struct serial_rs485 *rs485)
 {
@@ -211,10 +188,6 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
 	port->rs485_config = of_8250_rs485_config;
 
 	switch (type) {
-	case PORT_TEGRA:
-		port->handle_break = tegra_serial_handle_break;
-		break;
-
 	case PORT_RT2880:
 		port->iotype = UPIO_AU;
 		break;
@@ -359,7 +332,6 @@ static const struct of_device_id of_platform_serial_table[] = {
 	{ .compatible = "ns16550",  .data = (void *)PORT_16550, },
 	{ .compatible = "ns16750",  .data = (void *)PORT_16750, },
 	{ .compatible = "ns16850",  .data = (void *)PORT_16850, },
-	{ .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
 	{ .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
 	{ .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
 	{ .compatible = "intel,xscale-uart", .data = (void *)PORT_XSCALE, },
diff --git a/drivers/tty/serial/8250/8250_tegra.c b/drivers/tty/serial/8250/8250_tegra.c
new file mode 100644
index 000000000000..e639ce833132
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_tegra.c
@@ -0,0 +1,197 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  Serial Port driver for Tegra devices
+ *
+ *  Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved.
+ */
+
+#include <linux/acpi.h>
+#include <linux/clk.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+
+#include "8250.h"
+
+struct tegra_uart {
+	struct clk *clk;
+	struct reset_control *rst;
+	int line;
+};
+
+static void tegra_uart_handle_break(struct uart_port *p)
+{
+	unsigned int status, tmout = 10000;
+
+	do {
+		status = p->serial_in(p, UART_LSR);
+		if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
+			status = p->serial_in(p, UART_RX);
+		else
+			break;
+		if (--tmout == 0)
+			break;
+		udelay(1);
+	} while (1);
+}
+
+static int tegra_uart_probe(struct platform_device *pdev)
+{
+	struct uart_8250_port port8250;
+	struct tegra_uart *uart;
+	struct uart_port *port;
+	struct resource *res;
+	int ret;
+
+	uart = devm_kzalloc(&pdev->dev, sizeof(*uart), GFP_KERNEL);
+	if (!uart)
+		return -ENOMEM;
+
+	memset(&port8250, 0, sizeof(port8250));
+
+	port = &port8250.port;
+	spin_lock_init(&port->lock);
+
+	port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT |
+		      UPF_FIXED_TYPE;
+	port->iotype = UPIO_MEM32;
+	port->regshift = 2;
+	port->type = PORT_TEGRA;
+	port->irqflags |= IRQF_SHARED;
+	port->dev = &pdev->dev;
+	port->handle_break = tegra_uart_handle_break;
+
+	ret = of_alias_get_id(pdev->dev.of_node, "serial");
+	if (ret >= 0)
+		port->line = ret;
+
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0)
+		return ret;
+
+	port->irq = ret;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	port->membase = devm_ioremap(&pdev->dev, res->start,
+				     resource_size(res));
+	if (!port->membase)
+		return -ENOMEM;
+
+	port->mapbase = res->start;
+	port->mapsize = resource_size(res);
+
+	uart->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
+	if (IS_ERR(uart->rst))
+		return PTR_ERR(uart->rst);
+
+	if (device_property_read_u32(&pdev->dev, "clock-frequency",
+				     &port->uartclk)) {
+		uart->clk = devm_clk_get(&pdev->dev, NULL);
+		if (IS_ERR(uart->clk)) {
+			dev_err(&pdev->dev, "failed to get clock!\n");
+			return -ENODEV;
+		}
+
+		ret = clk_prepare_enable(uart->clk);
+		if (ret < 0)
+			return ret;
+
+		port->uartclk = clk_get_rate(uart->clk);
+	}
+
+	ret = reset_control_deassert(uart->rst);
+	if (ret)
+		goto err_clkdisable;
+
+	ret = serial8250_register_8250_port(&port8250);
+	if (ret < 0)
+		goto err_clkdisable;
+
+	platform_set_drvdata(pdev, uart);
+	uart->line = ret;
+
+	return 0;
+
+err_clkdisable:
+	clk_disable_unprepare(uart->clk);
+
+	return ret;
+}
+
+static int tegra_uart_remove(struct platform_device *pdev)
+{
+	struct tegra_uart *uart = platform_get_drvdata(pdev);
+
+	serial8250_unregister_port(uart->line);
+	reset_control_assert(uart->rst);
+	clk_disable_unprepare(uart->clk);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int tegra_uart_suspend(struct device *dev)
+{
+	struct tegra_uart *uart = dev_get_drvdata(dev);
+	struct uart_8250_port *port8250 = serial8250_get_port(uart->line);
+	struct uart_port *port = &port8250->port;
+
+	serial8250_suspend_port(uart->line);
+
+	if (!uart_console(port) || console_suspend_enabled)
+		clk_disable_unprepare(uart->clk);
+
+	return 0;
+}
+
+static int tegra_uart_resume(struct device *dev)
+{
+	struct tegra_uart *uart = dev_get_drvdata(dev);
+	struct uart_8250_port *port8250 = serial8250_get_port(uart->line);
+	struct uart_port *port = &port8250->port;
+
+	if (!uart_console(port) || console_suspend_enabled)
+		clk_prepare_enable(uart->clk);
+
+	serial8250_resume_port(uart->line);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(tegra_uart_pm_ops, tegra_uart_suspend,
+			 tegra_uart_resume);
+
+static const struct of_device_id tegra_uart_of_match[] = {
+	{ .compatible = "nvidia,tegra20-uart", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, tegra_uart_of_match);
+
+static const struct acpi_device_id tegra_uart_acpi_match[] = {
+	{ "NVDA0100", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, tegra_uart_acpi_match);
+
+static struct platform_driver tegra_uart_driver = {
+	.driver = {
+		.name = "tegra-uart",
+		.pm = &tegra_uart_pm_ops,
+		.of_match_table = tegra_uart_of_match,
+		.acpi_match_table = ACPI_PTR(tegra_uart_acpi_match),
+	},
+	.probe = tegra_uart_probe,
+	.remove = tegra_uart_remove,
+};
+
+module_platform_driver(tegra_uart_driver);
+
+MODULE_AUTHOR("Jeff Brasen <jbrasen@nvidia.com>");
+MODULE_DESCRIPTION("NVIDIA Tegra 8250 Driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index f16824bbb573..432b47647677 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -500,6 +500,15 @@ config SERIAL_8250_PXA
 	  applicable to both devicetree and legacy boards, and early console is
 	  part of its support.
 
+config SERIAL_8250_TEGRA
+	tristate "8250 support for Tegra serial ports"
+	default SERIAL_8250
+	depends on SERIAL_8250
+	depends on ARCH_TEGRA
+	help
+	  Select this option if you have machine with an NVIDIA Tegra SoC and
+	  wish to enable 8250 serial driver for the Tegra serial interfaces.
+
 config SERIAL_OF_PLATFORM
 	tristate "Devicetree based probing for 8250 ports"
 	depends on SERIAL_8250 && OF
diff --git a/drivers/tty/serial/8250/Makefile b/drivers/tty/serial/8250/Makefile
index 51a6079d3f1f..a8bfb654d490 100644
--- a/drivers/tty/serial/8250/Makefile
+++ b/drivers/tty/serial/8250/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_SERIAL_8250_INGENIC)	+= 8250_ingenic.o
 obj-$(CONFIG_SERIAL_8250_LPSS)		+= 8250_lpss.o
 obj-$(CONFIG_SERIAL_8250_MID)		+= 8250_mid.o
 obj-$(CONFIG_SERIAL_8250_PXA)		+= 8250_pxa.o
+obj-$(CONFIG_SERIAL_8250_TEGRA)		+= 8250_tegra.o
 obj-$(CONFIG_SERIAL_OF_PLATFORM)	+= 8250_of.o
 
 CFLAGS_8250_ingenic.o += -I$(srctree)/scripts/dtc/libfdt
-- 
2.17.1


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH] serial: 8250_tegra: Create Tegra specific 8250 driver
  2020-01-20 16:01 [PATCH] serial: 8250_tegra: Create Tegra specific 8250 driver Jon Hunter
@ 2020-01-21 15:41 ` Greg Kroah-Hartman
  2020-01-21 15:46   ` Jon Hunter
  2020-01-21 16:31 ` Dmitry Osipenko
  1 sibling, 1 reply; 7+ messages in thread
From: Greg Kroah-Hartman @ 2020-01-21 15:41 UTC (permalink / raw)
  To: Jon Hunter
  Cc: Jiri Slaby, Thierry Reding, linux-serial, linux-kernel,
	linux-tegra, Jeff Brasen

On Mon, Jan 20, 2020 at 04:01:49PM +0000, Jon Hunter wrote:
> diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
> index f16824bbb573..432b47647677 100644
> --- a/drivers/tty/serial/8250/Kconfig
> +++ b/drivers/tty/serial/8250/Kconfig
> @@ -500,6 +500,15 @@ config SERIAL_8250_PXA
>  	  applicable to both devicetree and legacy boards, and early console is
>  	  part of its support.
>  
> +config SERIAL_8250_TEGRA
> +	tristate "8250 support for Tegra serial ports"
> +	default SERIAL_8250
> +	depends on SERIAL_8250
> +	depends on ARCH_TEGRA

No COMPILE_TEST support so we can make sure we don't break the thing
somehow?

thanks,

greg k-h

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH] serial: 8250_tegra: Create Tegra specific 8250 driver
  2020-01-21 15:41 ` Greg Kroah-Hartman
@ 2020-01-21 15:46   ` Jon Hunter
  0 siblings, 0 replies; 7+ messages in thread
From: Jon Hunter @ 2020-01-21 15:46 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Jiri Slaby, Thierry Reding, linux-serial, linux-kernel,
	linux-tegra, Jeff Brasen


On 21/01/2020 15:41, Greg Kroah-Hartman wrote:
> On Mon, Jan 20, 2020 at 04:01:49PM +0000, Jon Hunter wrote:
>> diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
>> index f16824bbb573..432b47647677 100644
>> --- a/drivers/tty/serial/8250/Kconfig
>> +++ b/drivers/tty/serial/8250/Kconfig
>> @@ -500,6 +500,15 @@ config SERIAL_8250_PXA
>>  	  applicable to both devicetree and legacy boards, and early console is
>>  	  part of its support.
>>  
>> +config SERIAL_8250_TEGRA
>> +	tristate "8250 support for Tegra serial ports"
>> +	default SERIAL_8250
>> +	depends on SERIAL_8250
>> +	depends on ARCH_TEGRA
> 
> No COMPILE_TEST support so we can make sure we don't break the thing
> somehow?

Good point. Will add.

Thanks
Jon

-- 
nvpublic

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH] serial: 8250_tegra: Create Tegra specific 8250 driver
  2020-01-20 16:01 [PATCH] serial: 8250_tegra: Create Tegra specific 8250 driver Jon Hunter
  2020-01-21 15:41 ` Greg Kroah-Hartman
@ 2020-01-21 16:31 ` Dmitry Osipenko
  2020-01-21 16:37   ` Dmitry Osipenko
  2020-01-21 18:34   ` Jon Hunter
  1 sibling, 2 replies; 7+ messages in thread
From: Dmitry Osipenko @ 2020-01-21 16:31 UTC (permalink / raw)
  To: Jon Hunter, Greg Kroah-Hartman, Jiri Slaby, Thierry Reding
  Cc: linux-serial, linux-kernel, linux-tegra, Jeff Brasen

Hello Jon,

20.01.2020 19:01, Jon Hunter пишет:

[snip]

> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res)
> +		return -ENODEV;
> +
> +	port->membase = devm_ioremap(&pdev->dev, res->start,
> +				     resource_size(res));

devm_platform_ioremap_resource()

> +	if (!port->membase)
> +		return -ENOMEM;
> +
> +	port->mapbase = res->start;
> +	port->mapsize = resource_size(res);
> +
> +	uart->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);

Why reset is shared? It shall not be shared at least on T20/30/124/210..

[snip]

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH] serial: 8250_tegra: Create Tegra specific 8250 driver
  2020-01-21 16:31 ` Dmitry Osipenko
@ 2020-01-21 16:37   ` Dmitry Osipenko
  2020-01-21 18:34   ` Jon Hunter
  1 sibling, 0 replies; 7+ messages in thread
From: Dmitry Osipenko @ 2020-01-21 16:37 UTC (permalink / raw)
  To: Jon Hunter, Greg Kroah-Hartman, Jiri Slaby, Thierry Reding
  Cc: linux-serial, linux-kernel, linux-tegra, Jeff Brasen

21.01.2020 19:31, Dmitry Osipenko пишет:
> Hello Jon,
> 
> 20.01.2020 19:01, Jon Hunter пишет:
> 
> [snip]
> 
>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +	if (!res)
>> +		return -ENODEV;
>> +
>> +	port->membase = devm_ioremap(&pdev->dev, res->start,
>> +				     resource_size(res));
> 
> devm_platform_ioremap_resource()
> 
>> +	if (!port->membase)
>> +		return -ENOMEM;
>> +
>> +	port->mapbase = res->start;
>> +	port->mapsize = resource_size(res);
>> +
>> +	uart->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
> 
> Why reset is shared? It shall not be shared at least on T20/30/124/210..
> 
> [snip]
> 

Actually, looks like use of a shared reset for a not-really-shared reset
should be fine.

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH] serial: 8250_tegra: Create Tegra specific 8250 driver
  2020-01-21 16:31 ` Dmitry Osipenko
  2020-01-21 16:37   ` Dmitry Osipenko
@ 2020-01-21 18:34   ` Jon Hunter
  2020-01-21 18:46     ` Dmitry Osipenko
  1 sibling, 1 reply; 7+ messages in thread
From: Jon Hunter @ 2020-01-21 18:34 UTC (permalink / raw)
  To: Dmitry Osipenko, Greg Kroah-Hartman, Jiri Slaby, Thierry Reding
  Cc: linux-serial, linux-kernel, linux-tegra, Jeff Brasen


On 21/01/2020 16:31, Dmitry Osipenko wrote:
> Hello Jon,
> 
> 20.01.2020 19:01, Jon Hunter пишет:
> 
> [snip]
> 
>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +	if (!res)
>> +		return -ENODEV;
>> +
>> +	port->membase = devm_ioremap(&pdev->dev, res->start,
>> +				     resource_size(res));
> 
> devm_platform_ioremap_resource()

That would be ideal, but we cannot. The driver needs the res structure
as well later on.

Jon

-- 
nvpublic

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH] serial: 8250_tegra: Create Tegra specific 8250 driver
  2020-01-21 18:34   ` Jon Hunter
@ 2020-01-21 18:46     ` Dmitry Osipenko
  0 siblings, 0 replies; 7+ messages in thread
From: Dmitry Osipenko @ 2020-01-21 18:46 UTC (permalink / raw)
  To: Jon Hunter, Greg Kroah-Hartman, Jiri Slaby, Thierry Reding
  Cc: linux-serial, linux-kernel, linux-tegra, Jeff Brasen

21.01.2020 21:34, Jon Hunter пишет:
> 
> On 21/01/2020 16:31, Dmitry Osipenko wrote:
>> Hello Jon,
>>
>> 20.01.2020 19:01, Jon Hunter пишет:
>>
>> [snip]
>>
>>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>> +	if (!res)
>>> +		return -ENODEV;
>>> +
>>> +	port->membase = devm_ioremap(&pdev->dev, res->start,
>>> +				     resource_size(res));
>>
>> devm_platform_ioremap_resource()
> 
> That would be ideal, but we cannot. The driver needs the res structure
> as well later on.

Oh, indeed.

^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, back to index

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-01-20 16:01 [PATCH] serial: 8250_tegra: Create Tegra specific 8250 driver Jon Hunter
2020-01-21 15:41 ` Greg Kroah-Hartman
2020-01-21 15:46   ` Jon Hunter
2020-01-21 16:31 ` Dmitry Osipenko
2020-01-21 16:37   ` Dmitry Osipenko
2020-01-21 18:34   ` Jon Hunter
2020-01-21 18:46     ` Dmitry Osipenko

Linux-Serial Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-serial/0 linux-serial/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-serial linux-serial/ https://lore.kernel.org/linux-serial \
		linux-serial@vger.kernel.org
	public-inbox-index linux-serial

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-serial


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git