[PATCH 5.6 163/167] Revert "serial: uartps: Register own uart console and driver structures"

From: Greg Kroah-Hartman
Date: Tue Apr 28 2020 - 14:49:04 EST


From: Michal Simek <michal.simek@xxxxxxxxxx>

commit 18cc7ac8a28e28cd005c2475f52576cfe10cabfb upstream.

This reverts commit 024ca329bfb9a948f76eaff3243e21b7e70182f2.

As Johan says, this driver needs a lot more work and these changes are
only going in the wrong direction:
https://lkml.kernel.org/r/20190523091839.GC568@localhost

Reported-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/1ee35667e36a8efddee381df5fe495ad65f4d15c.1585905873.git.michal.simek@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/tty/serial/xilinx_uartps.c | 95 +++++++++++++++----------------------
1 file changed, 40 insertions(+), 55 deletions(-)

--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -27,6 +27,7 @@
#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 16
#define CDNS_UART_FIFO_SIZE 64 /* FIFO size */
#define CDNS_UART_REGISTER_SPACE 0x1000
@@ -1144,6 +1145,8 @@ static const struct uart_ops cdns_uart_o
#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
@@ -1283,6 +1286,16 @@ static int cdns_uart_console_setup(struc

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
@@ -1414,6 +1427,9 @@ static const struct of_device_id cdns_ua
};
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
@@ -1427,11 +1443,6 @@ static int cdns_uart_probe(struct platfo
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);
@@ -1441,12 +1452,6 @@ static int cdns_uart_probe(struct platfo
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)
@@ -1457,50 +1462,25 @@ static int cdns_uart_probe(struct platfo
return -ENODEV;
}

- /* 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;
-
+ 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;
#ifdef CONFIG_SERIAL_XILINX_PS_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;
+ 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;
-
- /*
- * 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;
+ cdns_uart_data->cdns_uart_driver = &cdns_uart_uart_driver;

match = of_match_node(cdns_uart_of_match, pdev->dev.of_node);
if (match && match->data) {
@@ -1578,6 +1558,7 @@ static int cdns_uart_probe(struct platfo
port->ops = &cdns_uart_ops;
port->fifosize = CDNS_UART_FIFO_SIZE;
port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_XILINX_PS_UART_CONSOLE);
+ port->line = id;

/*
* Register the port.
@@ -1609,7 +1590,7 @@ static int cdns_uart_probe(struct platfo
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);
@@ -1619,12 +1600,15 @@ static int cdns_uart_probe(struct platfo
#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

cdns_uart_data->cts_override = of_property_read_bool(pdev->dev.of_node,
"cts-override");
+
+ instances++;
+
return 0;

err_out_pm_disable:
@@ -1640,8 +1624,8 @@ err_out_clk_disable:
err_out_clk_dis_pclk:
clk_disable_unprepare(cdns_uart_data->pclk);
err_out_unregister_driver:
- uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
-
+ if (!instances)
+ uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
return rc;
}

@@ -1676,7 +1660,8 @@ static int cdns_uart_remove(struct platf
console_port = NULL;
#endif

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