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Subject[LINUX PATCHv3 8/9] serial-uartlite: Remove ULITE_NR_PORTS macro
Date
From: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>

This patch is removing ULITE_NR_PORTS macro which limits number of
ports which can be used. Every instance is registering own struct
uart_driver with minor number which corresponds to alias ID (or 0 now).
and with 1 uart port. The same alias ID is saved to
tty_driver->name_base which is key field for creating ttyULX name.

Because name_base and minor number are setup already there is no need to
setup any port->line number because 0 is the right value.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
---
v2:
Remove the stray unrelated changes
v3:
Fix a compile error

drivers/tty/serial/uartlite.c | 249 ++++++++++++++++++++++++++++++------------
1 file changed, 179 insertions(+), 70 deletions(-)

diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
index 20fe11f..a118b8e 100644
--- a/drivers/tty/serial/uartlite.c
+++ b/drivers/tty/serial/uartlite.c
@@ -27,7 +27,6 @@
#define ULITE_NAME "ttyUL"
#define ULITE_MAJOR 204
#define ULITE_MINOR 187
-#define ULITE_NR_UARTS CONFIG_SERIAL_UARTLITE_NR_UARTS

/* ---------------------------------------------------------------------
* Register definitions
@@ -65,6 +64,7 @@ static struct uart_port *console_port;
struct uartlite_data {
const struct uartlite_reg_ops *reg_ops;
struct clk *clk;
+ int id;
struct uart_driver *ulite_uart_driver;
};

@@ -117,7 +117,6 @@ static inline void uart_out32(u32 val, u32 offset, struct uart_port *port)
pdata->reg_ops->out(val, port->membase + offset);
}

-static struct uart_port ulite_ports[ULITE_NR_UARTS];

/* ---------------------------------------------------------------------
* Core UART driver operations
@@ -535,18 +534,6 @@ static int ulite_console_setup(struct console *co, char *options)
return uart_set_options(port, co, baud, parity, bits, flow);
}

-static struct uart_driver ulite_uart_driver;
-
-static struct console ulite_console = {
- .name = ULITE_NAME,
- .write = ulite_console_write,
- .device = uart_console_device,
- .setup = ulite_console_setup,
- .flags = CON_PRINTBUFFER,
- .index = -1, /* Specified on the cmdline (e.g. console=ttyUL0 ) */
- .data = &ulite_uart_driver,
-};
-
static void early_uartlite_putc(struct uart_port *port, int c)
{
/*
@@ -590,18 +577,6 @@ OF_EARLYCON_DECLARE(uartlite_a, "xlnx,xps-uartlite-1.00.a", early_uartlite_setup

#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */

-static struct uart_driver ulite_uart_driver = {
- .owner = THIS_MODULE,
- .driver_name = "uartlite",
- .dev_name = ULITE_NAME,
- .major = ULITE_MAJOR,
- .minor = ULITE_MINOR,
- .nr = ULITE_NR_UARTS,
-#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
- .cons = &ulite_console,
-#endif
-};
-
/* ---------------------------------------------------------------------
* Port assignment functions (mapping devices to uart_port structures)
*/
@@ -622,24 +597,9 @@ static int ulite_assign(struct device *dev, int id, u32 base, int irq,
struct uart_port *port;
int rc;

- /* if id = -1; then scan for a free id and use that */
- if (id < 0) {
- for (id = 0; id < ULITE_NR_UARTS; id++)
- if (ulite_ports[id].mapbase == 0)
- break;
- }
- if (id < 0 || id >= ULITE_NR_UARTS) {
- dev_err(dev, "%s%i too large\n", ULITE_NAME, id);
- return -EINVAL;
- }
-
- if ((ulite_ports[id].mapbase) && (ulite_ports[id].mapbase != base)) {
- dev_err(dev, "cannot assign to %s%i; it is already in use\n",
- ULITE_NAME, id);
- return -EBUSY;
- }
-
- port = &ulite_ports[id];
+ port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
+ if (!port)
+ return -ENOMEM;

spin_lock_init(&port->lock);
port->fifosize = 16;
@@ -653,7 +613,6 @@ static int ulite_assign(struct device *dev, int id, u32 base, int irq,
port->flags = UPF_BOOT_AUTOCONF;
port->dev = dev;
port->type = PORT_UNKNOWN;
- port->line = id;
port->private_data = pdata;

dev_set_drvdata(dev, port);
@@ -778,11 +737,24 @@ static const struct of_device_id ulite_of_match[] = {
MODULE_DEVICE_TABLE(of, ulite_of_match);
#endif /* CONFIG_OF */

-static int ulite_probe(struct platform_device *pdev)
+/*
+ * 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 256
+
+/* 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 ulite_get_id(struct platform_device *pdev)
{
- struct resource *res;
- struct uartlite_data *pdata;
- int irq, ret;
+ int ret;
int id = pdev->id;
#ifdef CONFIG_OF
const __be32 *prop;
@@ -790,40 +762,158 @@ static int ulite_probe(struct platform_device *pdev)
prop = of_get_property(pdev->dev.of_node, "port-number", NULL);
if (prop)
id = be32_to_cpup(prop);
+
+ /* Alias list is stable that's why get alias bitmap only once */
+ if (!alias_bitmap_initialized) {
+ ret = of_alias_get_alias_list(ulite_of_match, "serial",
+ alias_bitmap, MAX_UART_INSTANCES);
+ if (ret)
+ return ret;
+
+ alias_bitmap_initialized++;
+ }
+
#endif
- if (id < 0) {
- /* Look for a serialN alias */
+
+ mutex_lock(&bitmap_lock);
+
+ /* 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 */
+ if (id < 0)
id = of_alias_get_id(pdev->dev.of_node, "serial");
- if (id < 0)
- id = 0;
- }

- if (!ulite_uart_driver.state) {
- dev_dbg(&pdev->dev, "uartlite: calling uart_register_driver()\n");
- ret = uart_register_driver(&ulite_uart_driver);
- if (ret < 0) {
- dev_err(&pdev->dev, "Failed to register driver\n");
- return ret;
+ 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;
+}
+
+static int ulite_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+ struct uartlite_data *pdata;
+ int irq, ret;
+ struct uart_driver *ulite_uart_driver;
+ char *driver_name;
+#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
+ struct console *ulite_console;
+#endif
+
pdata = devm_kzalloc(&pdev->dev, sizeof(struct uartlite_data),
GFP_KERNEL);
if (!pdata)
return -ENOMEM;

+ ulite_uart_driver = devm_kzalloc(&pdev->dev,
+ sizeof(*ulite_uart_driver),
+ GFP_KERNEL);
+ if (!ulite_uart_driver)
+ return -ENOMEM;
+
+ pdata->id = ulite_get_id(pdev);
+ if (pdata->id < 0)
+ return pdata->id;
+
+ /* There is a need to use unique driver name */
+ driver_name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s%d",
+ ULITE_NAME, pdata->id);
+ if (!driver_name) {
+ ret = -ENOMEM;
+ goto err_out_id;
+ }
+
+ ulite_uart_driver->owner = THIS_MODULE;
+ ulite_uart_driver->driver_name = driver_name;
+ ulite_uart_driver->dev_name = ULITE_NAME;
+ ulite_uart_driver->major = ULITE_MAJOR;
+ ulite_uart_driver->minor = pdata->id;
+ ulite_uart_driver->nr = 1;
+#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
+ ulite_console = devm_kzalloc(&pdev->dev, sizeof(*ulite_console),
+ GFP_KERNEL);
+ if (!ulite_console) {
+ ret = -ENOMEM;
+ goto err_out_id;
+ }
+
+ strncpy(ulite_console->name, ULITE_NAME,
+ sizeof(ulite_console->name));
+ ulite_console->index = pdata->id;
+ ulite_console->write = ulite_console_write;
+ ulite_console->device = uart_console_device;
+ ulite_console->setup = ulite_console_setup;
+ ulite_console->flags = CON_PRINTBUFFER;
+ ulite_uart_driver->cons = ulite_console;
+ ulite_console->data = ulite_uart_driver;
+#endif
+
+ dev_dbg(&pdev->dev, "uartlite: calling uart_register_driver()\n");
+ ret = uart_register_driver(ulite_uart_driver);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to register driver\n");
+ goto err_out_id;
+ }
+
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (!res)
- return -ENODEV;
+ if (!res) {
+ ret = -ENODEV;
+ goto err_out_unregister_driver;
+ }

irq = platform_get_irq(pdev, 0);
- if (irq <= 0)
- return -ENXIO;
+ if (irq <= 0) {
+ ret = -ENXIO;
+ goto err_out_unregister_driver;
+ }

pdata->clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
if (IS_ERR(pdata->clk)) {
- if (PTR_ERR(pdata->clk) != -ENOENT)
- return PTR_ERR(pdata->clk);
+ if (PTR_ERR(pdata->clk) != -ENOENT) {
+ ret = PTR_ERR(pdata->clk);
+ goto err_out_unregister_driver;
+ }

/*
* Clock framework support is optional, continue on
@@ -832,11 +922,10 @@ static int ulite_probe(struct platform_device *pdev)
pdata->clk = NULL;
}

- pdata->ulite_uart_driver = &ulite_uart_driver;
ret = clk_prepare_enable(pdata->clk);
if (ret) {
dev_err(&pdev->dev, "Failed to prepare clock\n");
- return ret;
+ goto err_out_unregister_driver;
}

pm_runtime_use_autosuspend(&pdev->dev);
@@ -844,11 +933,27 @@ static int ulite_probe(struct platform_device *pdev)
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);

- ret = ulite_assign(&pdev->dev, id, res->start, irq, pdata);
+ ulite_uart_driver->tty_driver->name_base = pdata->id;
+ pdata->ulite_uart_driver = ulite_uart_driver;
+ ret = ulite_assign(&pdev->dev, pdata->id, res->start, irq, pdata);
+ if (ret < 0)
+ goto err_out_clk_disable;

pm_runtime_mark_last_busy(&pdev->dev);
pm_runtime_put_autosuspend(&pdev->dev);
+ return 0;

+err_out_clk_disable:
+ clk_disable_unprepare(pdata->clk);
+ pm_runtime_disable(&pdev->dev);
+ pm_runtime_set_suspended(&pdev->dev);
+ pm_runtime_dont_use_autosuspend(&pdev->dev);
+err_out_unregister_driver:
+ uart_unregister_driver(pdata->ulite_uart_driver);
+err_out_id:
+ mutex_lock(&bitmap_lock);
+ clear_bit(pdata->id, bitmap);
+ mutex_unlock(&bitmap_lock);
return ret;
}

@@ -860,11 +965,16 @@ static int ulite_remove(struct platform_device *pdev)

clk_unprepare(pdata->clk);
rc = ulite_release(&pdev->dev);
+ mutex_lock(&bitmap_lock);
+ clear_bit(pdata->id, bitmap);
+ mutex_unlock(&bitmap_lock);
+
#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
if (console_port == port)
console_port = NULL;
#endif

+ uart_unregister_driver(pdata->ulite_uart_driver);
pm_runtime_disable(&pdev->dev);
pm_runtime_set_suspended(&pdev->dev);
pm_runtime_dont_use_autosuspend(&pdev->dev);
@@ -898,7 +1008,6 @@ static int __init ulite_init(void)
static void __exit ulite_exit(void)
{
platform_driver_unregister(&ulite_platform_driver);
- uart_unregister_driver(&ulite_uart_driver);
}

module_init(ulite_init);
--
2.1.1
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