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Subject[PATCH v3 09/10] serial: uartps: Register own uart console and driver structures
Date
Every instance is registering own struct console and struct uart_driver
with minor number which corresponds to alias ID (or 0 now) and with 1 uart
port. The same alias ID is saved to tty_driver->name_base which is key
field for creating ttyPSX name.

Because name_base and minor number are setup already there is no need to
setup any port->line number because 0 is the right value.

Unfortunately this driver is setting up major number to 0 for using
dynamic assignment and kernel is allocating different major numbers for
every instance instead of using the same major and different minor
number.

~# ls -la /dev/ttyPS*
crw------- 1 root root 252, 0 Jan 1 03:36 /dev/ttyPS0
crw--w---- 1 root root 253, 1 Jan 1 00:00 /dev/ttyPS1

When major number is not 0. For example 252 then major/minor
combinations are in expected form

~# ls -la /dev/ttyPS*
crw------- 1 root root 252, 0 Jan 1 04:04 /dev/ttyPS0
crw--w---- 1 root root 252, 1 Jan 1 00:00 /dev/ttyPS1

Driver is not freeing struct cdns_uart_console in case that instance is
not used as console. The reason is that console is incorrectly unregistred
and "console [0] disabled" message will be shown.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
---

Changes in v3:
- Rebase on the top of previous broken patch
- Change patch subject ("was serial: uartps: Remove CDNS_UART_NR_PORTS
macro")
- Keep CDNS_UART_NR_PORTS in this patch and remove it in next one and
align commit message to reflect this
- Allocate struct console dynamically too to be unique for every
instance
- Cleanup error path

Changes in v2:
- Register one uart_driver with unique minor at probe time

---
drivers/tty/serial/xilinx_uartps.c | 93 ++++++++++++++++++++++----------------
1 file changed, 55 insertions(+), 38 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 0e578c0a8ce0..d838612eda6f 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -30,7 +30,6 @@
#define CDNS_UART_TTY_NAME "ttyPS"
#define CDNS_UART_NAME "xuartps"
#define CDNS_UART_MAJOR 0 /* use dynamic node allocation */
-#define CDNS_UART_MINOR 0 /* works best with devtmpfs */
#define CDNS_UART_NR_PORTS 2
#define CDNS_UART_FIFO_SIZE 64 /* FIFO size */
#define CDNS_UART_REGISTER_SPACE 0x1000
@@ -1099,8 +1098,6 @@ static void cdns_uart_pm(struct uart_port *port, unsigned int state,
#endif
};

-static struct uart_driver cdns_uart_uart_driver;
-
#ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
/**
* cdns_uart_console_putchar - write the character to the FIFO buffer
@@ -1240,16 +1237,6 @@ static int cdns_uart_console_setup(struct console *co, char *options)

return uart_set_options(port, co, baud, parity, bits, flow);
}
-
-static struct console cdns_uart_console = {
- .name = CDNS_UART_TTY_NAME,
- .write = cdns_uart_console_write,
- .device = uart_console_device,
- .setup = cdns_uart_console_setup,
- .flags = CON_PRINTBUFFER,
- .index = -1, /* Specified on the cmdline (e.g. console=ttyPS ) */
- .data = &cdns_uart_uart_driver,
-};
#endif /* CONFIG_SERIAL_XILINX_PS_UART_CONSOLE */

#ifdef CONFIG_PM_SLEEP
@@ -1381,9 +1368,6 @@ static int __maybe_unused cdns_runtime_resume(struct device *dev)
};
MODULE_DEVICE_TABLE(of, cdns_uart_of_match);

-/* Temporary variable for storing number of instances */
-static int instances;
-
/**
* cdns_uart_probe - Platform driver probe
* @pdev: Pointer to the platform device structure
@@ -1397,6 +1381,11 @@ static int cdns_uart_probe(struct platform_device *pdev)
struct resource *res;
struct cdns_uart *cdns_uart_data;
const struct of_device_id *match;
+ struct uart_driver *cdns_uart_uart_driver;
+ char *driver_name;
+#ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
+ struct console *cdns_uart_console;
+#endif

cdns_uart_data = devm_kzalloc(&pdev->dev, sizeof(*cdns_uart_data),
GFP_KERNEL);
@@ -1406,6 +1395,12 @@ static int cdns_uart_probe(struct platform_device *pdev)
if (!port)
return -ENOMEM;

+ cdns_uart_uart_driver = devm_kzalloc(&pdev->dev,
+ sizeof(*cdns_uart_uart_driver),
+ GFP_KERNEL);
+ if (!cdns_uart_uart_driver)
+ return -ENOMEM;
+
/* Look for a serialN alias */
id = of_alias_get_id(pdev->dev.of_node, "serial");
if (id < 0)
@@ -1416,25 +1411,50 @@ static int cdns_uart_probe(struct platform_device *pdev)
return -ENODEV;
}

- if (!cdns_uart_uart_driver.state) {
- cdns_uart_uart_driver.owner = THIS_MODULE;
- cdns_uart_uart_driver.driver_name = CDNS_UART_NAME;
- cdns_uart_uart_driver.dev_name = CDNS_UART_TTY_NAME;
- cdns_uart_uart_driver.major = CDNS_UART_MAJOR;
- cdns_uart_uart_driver.minor = CDNS_UART_MINOR;
- cdns_uart_uart_driver.nr = CDNS_UART_NR_PORTS;
+ /* There is a need to use unique driver name */
+ driver_name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s%d",
+ CDNS_UART_NAME, id);
+ if (!driver_name)
+ return -ENOMEM;
+
+ cdns_uart_uart_driver->owner = THIS_MODULE;
+ cdns_uart_uart_driver->driver_name = driver_name;
+ cdns_uart_uart_driver->dev_name = CDNS_UART_TTY_NAME;
+ cdns_uart_uart_driver->major = CDNS_UART_MAJOR;
+ cdns_uart_uart_driver->minor = id;
+ cdns_uart_uart_driver->nr = 1;
+
#ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
- cdns_uart_uart_driver.cons = &cdns_uart_console;
+ cdns_uart_console = devm_kzalloc(&pdev->dev, sizeof(*cdns_uart_console),
+ GFP_KERNEL);
+ if (!cdns_uart_console)
+ return -ENOMEM;
+
+ strncpy(cdns_uart_console->name, CDNS_UART_TTY_NAME,
+ sizeof(cdns_uart_console->name));
+ cdns_uart_console->index = id;
+ cdns_uart_console->write = cdns_uart_console_write;
+ cdns_uart_console->device = uart_console_device;
+ cdns_uart_console->setup = cdns_uart_console_setup;
+ cdns_uart_console->flags = CON_PRINTBUFFER;
+ cdns_uart_console->data = cdns_uart_uart_driver;
+ cdns_uart_uart_driver->cons = cdns_uart_console;
#endif

- rc = uart_register_driver(&cdns_uart_uart_driver);
- if (rc < 0) {
- dev_err(&pdev->dev, "Failed to register driver\n");
- return rc;
- }
+ rc = uart_register_driver(cdns_uart_uart_driver);
+ if (rc < 0) {
+ dev_err(&pdev->dev, "Failed to register driver\n");
+ return rc;
}

- cdns_uart_data->cdns_uart_driver = &cdns_uart_uart_driver;
+ cdns_uart_data->cdns_uart_driver = cdns_uart_uart_driver;
+
+ /*
+ * Setting up proper name_base needs to be done after uart
+ * registration because tty_driver structure is not filled.
+ * name_base is 0 by default.
+ */
+ cdns_uart_uart_driver->tty_driver->name_base = id;

match = of_match_node(cdns_uart_of_match, pdev->dev.of_node);
if (match && match->data) {
@@ -1505,7 +1525,6 @@ static int cdns_uart_probe(struct platform_device *pdev)
port->flags = UPF_BOOT_AUTOCONF;
port->ops = &cdns_uart_ops;
port->fifosize = CDNS_UART_FIFO_SIZE;
- port->line = id;

/*
* Register the port.
@@ -1536,7 +1555,7 @@ static int cdns_uart_probe(struct platform_device *pdev)
console_port = port;
#endif

- rc = uart_add_one_port(&cdns_uart_uart_driver, port);
+ rc = uart_add_one_port(cdns_uart_uart_driver, port);
if (rc) {
dev_err(&pdev->dev,
"uart_add_one_port() failed; err=%i\n", rc);
@@ -1546,11 +1565,10 @@ static int cdns_uart_probe(struct platform_device *pdev)
#ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
/* This is not port which is used for console that's why clean it up */
if (console_port == port &&
- !(cdns_uart_uart_driver.cons->flags & CON_ENABLED))
+ !(cdns_uart_uart_driver->cons->flags & CON_ENABLED))
console_port = NULL;
#endif

- instances++;
return 0;

err_out_pm_disable:
@@ -1566,8 +1584,8 @@ static int cdns_uart_probe(struct platform_device *pdev)
err_out_clk_dis_pclk:
clk_disable_unprepare(cdns_uart_data->pclk);
err_out_unregister_driver:
- if (!instances)
- uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
+ uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
+
return rc;
}

@@ -1601,8 +1619,7 @@ static int cdns_uart_remove(struct platform_device *pdev)
console_port = NULL;
#endif

- if (!--instances)
- uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
+ uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
return rc;
}

--
1.9.1
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