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Revert "serial: uartps: Change uart ID port allocation"

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This reverts commit ae1cca3fa3.

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>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/a94931b65ce0089f76fb1fe6b446a08731bff754.1585905873.git.michal.simek@xilinx.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Michal Simek 2020-04-03 11:24:34 +02:00 committed by Greg Kroah-Hartman
parent 91c9dfa25c
commit 72d6819728
1 changed files with 13 additions and 98 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

111
drivers/tty/serial/xilinx_uartps.c
View File

@ -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 @@ 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);
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);