diff options
| -rw-r--r-- | drivers/tty/serial/xilinx_uartps.c | 109 |
1 files changed, 96 insertions, 13 deletions
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index 71c032744dae..f77200a0f461 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_NR_PORTS 2 #define CDNS_UART_FIFO_SIZE 64 /* FIFO size */ #define CDNS_UART_REGISTER_SPACE 0x1000 @@ -1370,6 +1369,88 @@ 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) + 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 @@ -1403,21 +1484,17 @@ static int cdns_uart_probe(struct platform_device *pdev) if (!cdns_uart_uart_driver) return -ENOMEM; - /* Look for a serialN alias */ - cdns_uart_data->id = of_alias_get_id(pdev->dev.of_node, "serial"); + cdns_uart_data->id = cdns_get_id(pdev); if (cdns_uart_data->id < 0) - 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; - } + return cdns_uart_data->id; /* 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) - return -ENOMEM; + if (!driver_name) { + rc = -ENOMEM; + goto err_out_id; + } cdns_uart_uart_driver->owner = THIS_MODULE; cdns_uart_uart_driver->driver_name = driver_name; @@ -1446,7 +1523,7 @@ 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"); - return rc; + goto err_out_id; } cdns_uart_data->cdns_uart_driver = cdns_uart_uart_driver; @@ -1587,7 +1664,10 @@ 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; } @@ -1610,6 +1690,9 @@ 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); |