lkml.org 
[lkml]   [2020]   [Apr]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 5/7] Revert "serial: uartps: Change uart ID port allocation"
Date
This reverts commit ae1cca3fa3478be92948dbbcd722390272032ade.

With setting up NR_PORTS to 16 to be able to use serial2 and higher
aliases and don't loose functionality which was intended by these changes.

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

drivers/tty/serial/xilinx_uartps.c | 111 ++++-------------------------
1 file changed, 13 insertions(+), 98 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 9db3cd120057..58f0fa07ecdb 100644
--- 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_NR_PORTS 16
#define CDNS_UART_FIFO_SIZE 64 /* FIFO size */
#define CDNS_UART_REGISTER_SPACE 0x1000
#define TX_TIMEOUT 500000
@@ -1403,90 +1404,6 @@ static const struct of_device_id cdns_uart_of_match[] = {
};
MODULE_DEVICE_TABLE(of, cdns_uart_of_match);

-/*
- * Maximum number of instances without alias IDs but if there is alias
- * which target "< MAX_UART_INSTANCES" range this ID can't be used.
- */
-#define MAX_UART_INSTANCES 32
-
-/* Stores static aliases list */
-static DECLARE_BITMAP(alias_bitmap, MAX_UART_INSTANCES);
-static int alias_bitmap_initialized;
-
-/* Stores actual bitmap of allocated IDs with alias IDs together */
-static DECLARE_BITMAP(bitmap, MAX_UART_INSTANCES);
-/* Protect bitmap operations to have unique IDs */
-static DEFINE_MUTEX(bitmap_lock);
-
-static int cdns_get_id(struct platform_device *pdev)
-{
- int id, ret;
-
- mutex_lock(&bitmap_lock);
-
- /* Alias list is stable that's why get alias bitmap only once */
- if (!alias_bitmap_initialized) {
- ret = of_alias_get_alias_list(cdns_uart_of_match, "serial",
- alias_bitmap, MAX_UART_INSTANCES);
- if (ret && ret != -EOVERFLOW) {
- mutex_unlock(&bitmap_lock);
- return ret;
- }
-
- alias_bitmap_initialized++;
- }
-
- /* Make sure that alias ID is not taken by instance without alias */
- bitmap_or(bitmap, bitmap, alias_bitmap, MAX_UART_INSTANCES);
-
- dev_dbg(&pdev->dev, "Alias bitmap: %*pb\n",
- MAX_UART_INSTANCES, bitmap);
-
- /* Look for a serialN alias */
- id = of_alias_get_id(pdev->dev.of_node, "serial");
- if (id < 0) {
- dev_warn(&pdev->dev,
- "No serial alias passed. Using the first free id\n");
-
- /*
- * Start with id 0 and check if there is no serial0 alias
- * which points to device which is compatible with this driver.
- * If alias exists then try next free position.
- */
- id = 0;
-
- for (;;) {
- dev_info(&pdev->dev, "Checking id %d\n", id);
- id = find_next_zero_bit(bitmap, MAX_UART_INSTANCES, id);
-
- /* No free empty instance */
- if (id == MAX_UART_INSTANCES) {
- dev_err(&pdev->dev, "No free ID\n");
- mutex_unlock(&bitmap_lock);
- return -EINVAL;
- }
-
- dev_dbg(&pdev->dev, "The empty id is %d\n", id);
- /* Check if ID is empty */
- if (!test_and_set_bit(id, bitmap)) {
- /* Break the loop if bit is taken */
- dev_dbg(&pdev->dev,
- "Selected ID %d allocation passed\n",
- id);
- break;
- }
- dev_dbg(&pdev->dev,
- "Selected ID %d allocation failed\n", id);
- /* if taking bit fails then try next one */
- id++;
- }
- }
-
- mutex_unlock(&bitmap_lock);
-
- return id;
-}
-
/**
* cdns_uart_probe - Platform driver probe
* @pdev: Pointer to the platform device structure
@@ -1520,17 +1437,21 @@ static int cdns_uart_probe(struct platform_device *pdev)
if (!cdns_uart_uart_driver)
return -ENOMEM;

- cdns_uart_data->id = cdns_get_id(pdev);
+ /* Look for a serialN alias */
+ cdns_uart_data->id = of_alias_get_id(pdev->dev.of_node, "serial");
if (cdns_uart_data->id < 0)
- return cdns_uart_data->id;
+ cdns_uart_data->id = 0;
+
+ if (cdns_uart_data->id >= CDNS_UART_NR_PORTS) {
+ dev_err(&pdev->dev, "Cannot get uart_port structure\n");
+ return -ENODEV;
+ }

/* There is a need to use unique driver name */
driver_name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s%d",
CDNS_UART_NAME, cdns_uart_data->id);
- if (!driver_name) {
- rc = -ENOMEM;
- goto err_out_id;
- }
+ if (!driver_name)
+ return -ENOMEM;

cdns_uart_uart_driver->owner = THIS_MODULE;
cdns_uart_uart_driver->driver_name = driver_name;
@@ -1559,7 +1480,7 @@ static int cdns_uart_probe(struct platform_device *pdev)
rc = uart_register_driver(cdns_uart_uart_driver);
if (rc < 0) {
dev_err(&pdev->dev, "Failed to register driver\n");
- goto err_out_id;
+ return rc;
}

cdns_uart_data->cdns_uart_driver = cdns_uart_uart_driver;
@@ -1710,10 +1631,7 @@ static int cdns_uart_probe(struct platform_device *pdev)
clk_disable_unprepare(cdns_uart_data->pclk);
err_out_unregister_driver:
uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
-err_out_id:
- mutex_lock(&bitmap_lock);
- clear_bit(cdns_uart_data->id, bitmap);
- mutex_unlock(&bitmap_lock);
+
return rc;
}

@@ -1736,9 +1654,6 @@ static int cdns_uart_remove(struct platform_device *pdev)
#endif
rc = uart_remove_one_port(cdns_uart_data->cdns_uart_driver, port);
port->mapbase = 0;
- mutex_lock(&bitmap_lock);
- clear_bit(cdns_uart_data->id, bitmap);
- mutex_unlock(&bitmap_lock);
clk_disable_unprepare(cdns_uart_data->uartclk);
clk_disable_unprepare(cdns_uart_data->pclk);
pm_runtime_disable(&pdev->dev);
--
2.26.0
\
 
 \ /
  Last update: 2020-04-03 11:25    [W:0.091 / U:2.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site