This is a note to let you know that I've just added the patch titled
Revert "serial: uartps: Change uart ID port allocation"
to my tty git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git in the tty-linus branch.
The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.
If you have any questions about this process, please let me know.
From 72d68197281e2ad313960504d10b0c41ff87fd55 Mon Sep 17 00:00:00 2001
From: Michal Simek michal.simek@xilinx.com Date: Fri, 3 Apr 2020 11:24:34 +0200 Subject: Revert "serial: uartps: Change uart ID port allocation"
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 Cc: stable stable@vger.kernel.org Link: https://lore.kernel.org/r/a94931b65ce0089f76fb1fe6b446a08731bff754.158590587... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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);