| Message ID | 20240226142514.1485246-4-andriy.shevchenko@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | serial: Add a helper to parse device properties and more | expand |
On Mon, Feb 26, 2024 at 04:19:19PM +0200, Andy Shevchenko wrote: > Several serial drivers want to read the same or similar set of > the port properties. Make a common helper for them. > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > --- > drivers/tty/serial/serial_port.c | 134 +++++++++++++++++++++++++++++++ > include/linux/serial_core.h | 1 + > 2 files changed, 135 insertions(+) > > diff --git a/drivers/tty/serial/serial_port.c b/drivers/tty/serial/serial_port.c > index 88975a4df306..ecc980e9dba6 100644 > --- a/drivers/tty/serial/serial_port.c > +++ b/drivers/tty/serial/serial_port.c > @@ -8,7 +8,10 @@ > > #include <linux/device.h> > #include <linux/module.h> > +#include <linux/of.h> > +#include <linux/platform_device.h> > #include <linux/pm_runtime.h> > +#include <linux/property.h> > #include <linux/serial_core.h> > #include <linux/spinlock.h> > > @@ -82,6 +85,137 @@ void uart_remove_one_port(struct uart_driver *drv, struct uart_port *port) > } > EXPORT_SYMBOL(uart_remove_one_port); > > +/** > + * uart_read_port_properties - read firmware properties of the given UART port I like, but: > + * @port: corresponding port > + * @use_defaults: apply defaults (when %true) or validate the values (when %false) Using random booleans in a function is horrid. Every time you see the function call, or want to call it, you need to go and look up what the boolean is and means. Make 2 public functions here, one that does it with use_defaults=true and one =false and then have them both call this one static function, that way the function names themselves are easy to read and understand and maintain over time. thanks, greg k-h > + * > + * The following device properties are supported: > + * - clock-frequency (optional) > + * - fifo-size (optional) > + * - no-loopback-test (optional) > + * - reg-shift (defaults may apply) > + * - reg-offset (value may be validated) > + * - reg-io-width (defaults may apply or value may be validated) > + * - interrupts (OF only) > + * - serial [alias ID] (OF only) > + * > + * If the port->dev is of struct platform_device type the interrupt line > + * will be retrieved via platform_get_irq() call against that device. > + * Otherwise it will be assigned by fwnode_irq_get() call. In both cases > + * the index 0 of the resource is used. > + * > + * The caller is responsible to initialize the following fields of the @port > + * ->dev (must be valid) > + * ->flags > + * ->mapbase > + * ->mapsize > + * ->regshift (if @use_defaults is false) > + * before calling this function. Alternatively the above mentioned fields > + * may be zeroed, in such case the only ones, that have associated properties > + * found, will be set to the respective values. > + * > + * If no error happened, the ->irq, ->mapbase, ->mapsize will be altered. > + * The ->iotype is always altered. > + * > + * When @use_defaults is true and the respective property is not found > + * the following values will be applied: > + * ->regshift = 0 > + * In this case IRQ must be provided, otherwise an error will be returned. > + * > + * When @use_defaults is false and the respective property is found > + * the following values will be validated: > + * - reg-io-width (->iotype) > + * - reg-offset (->mapsize against ->mapbase) > + * > + * Returns: 0 on success or negative errno on failure > + */ > +int uart_read_port_properties(struct uart_port *port, bool use_defaults) > +{ > + struct device *dev = port->dev; > + u32 value; > + int ret; > + > + /* Read optional UART functional clock frequency */ > + device_property_read_u32(dev, "clock-frequency", &port->uartclk); > + > + /* Read the registers alignment (default: 8-bit) */ > + ret = device_property_read_u32(dev, "reg-shift", &value); > + if (ret) > + port->regshift = use_defaults ? 0 : port->regshift; > + else > + port->regshift = value; > + > + /* Read the registers I/O access type (default: MMIO 8-bit) */ > + ret = device_property_read_u32(dev, "reg-io-width", &value); > + if (ret) { > + port->iotype = UPIO_MEM; > + } else { > + switch (value) { > + case 1: > + port->iotype = UPIO_MEM; > + break; > + case 2: > + port->iotype = UPIO_MEM16; > + break; > + case 4: > + port->iotype = device_is_big_endian(dev) ? UPIO_MEM32BE : UPIO_MEM32; > + break; > + default: > + if (!use_defaults) { > + dev_err(dev, "Unsupported reg-io-width (%u)\n", value); > + return -EINVAL; > + } > + port->iotype = UPIO_UNKNOWN; > + break; > + } > + } > + > + /* Read the address mapping base offset (default: no offset) */ > + ret = device_property_read_u32(dev, "reg-offset", &value); > + if (ret) > + value = 0; > + > + /* Check for shifted address mapping overflow */ > + if (!use_defaults && port->mapsize < value) { > + dev_err(dev, "reg-offset %u exceeds region size %pa\n", value, &port->mapsize); > + return -EINVAL; > + } > + > + port->mapbase += value; > + port->mapsize -= value; > + > + /* Read optional FIFO size */ > + device_property_read_u32(dev, "fifo-size", &port->fifosize); > + > + if (device_property_read_bool(dev, "no-loopback-test")) > + port->flags |= UPF_SKIP_TEST; > + > + /* Get index of serial line, if found in DT aliases */ > + ret = of_alias_get_id(dev_of_node(dev), "serial"); > + if (ret >= 0) > + port->line = ret; > + > + if (dev_is_platform(dev)) > + ret = platform_get_irq(to_platform_device(dev), 0); > + else > + ret = fwnode_irq_get(dev_fwnode(dev), 0); > + if (ret == -EPROBE_DEFER) > + return ret; > + if (ret > 0) > + port->irq = ret; > + else if (use_defaults) > + /* By default IRQ support is mandatory */ > + return ret; > + else > + port->irq = 0; > + > + port->flags |= UPF_SHARE_IRQ; > + > + return 0; > +} > +EXPORT_SYMBOL(uart_read_port_properties); EXPORT_SYMBOL_GPL()? I have to ask :) thanks, greg k-h
On Sat, Mar 02, 2024 at 09:58:53PM +0100, Greg Kroah-Hartman wrote: > On Mon, Feb 26, 2024 at 04:19:19PM +0200, Andy Shevchenko wrote: ... > > + * uart_read_port_properties - read firmware properties of the given UART port > > I like, but: > > > + * @port: corresponding port > > + * @use_defaults: apply defaults (when %true) or validate the values (when %false) > > Using random booleans in a function is horrid. Every time you see the > function call, or want to call it, you need to go and look up what the > boolean is and means. > > Make 2 public functions here, one that does it with use_defaults=true > and one =false and then have them both call this one static function, > that way the function names themselves are easy to read and understand > and maintain over time. Okay! I'll redo that. ... > > +EXPORT_SYMBOL(uart_read_port_properties); > > EXPORT_SYMBOL_GPL()? I have to ask :) No clue, the rest in this file is EXPORT_SYMBOL, but I admit I followed the cargo cult. I'll check the modified code and see if I may use _GPL version. Thank you for review!
diff --git a/drivers/tty/serial/serial_port.c b/drivers/tty/serial/serial_port.c index 88975a4df306..ecc980e9dba6 100644 --- a/drivers/tty/serial/serial_port.c +++ b/drivers/tty/serial/serial_port.c @@ -8,7 +8,10 @@ #include <linux/device.h> #include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> #include <linux/pm_runtime.h> +#include <linux/property.h> #include <linux/serial_core.h> #include <linux/spinlock.h> @@ -82,6 +85,137 @@ void uart_remove_one_port(struct uart_driver *drv, struct uart_port *port) } EXPORT_SYMBOL(uart_remove_one_port); +/** + * uart_read_port_properties - read firmware properties of the given UART port + * @port: corresponding port + * @use_defaults: apply defaults (when %true) or validate the values (when %false) + * + * The following device properties are supported: + * - clock-frequency (optional) + * - fifo-size (optional) + * - no-loopback-test (optional) + * - reg-shift (defaults may apply) + * - reg-offset (value may be validated) + * - reg-io-width (defaults may apply or value may be validated) + * - interrupts (OF only) + * - serial [alias ID] (OF only) + * + * If the port->dev is of struct platform_device type the interrupt line + * will be retrieved via platform_get_irq() call against that device. + * Otherwise it will be assigned by fwnode_irq_get() call. In both cases + * the index 0 of the resource is used. + * + * The caller is responsible to initialize the following fields of the @port + * ->dev (must be valid) + * ->flags + * ->mapbase + * ->mapsize + * ->regshift (if @use_defaults is false) + * before calling this function. Alternatively the above mentioned fields + * may be zeroed, in such case the only ones, that have associated properties + * found, will be set to the respective values. + * + * If no error happened, the ->irq, ->mapbase, ->mapsize will be altered. + * The ->iotype is always altered. + * + * When @use_defaults is true and the respective property is not found + * the following values will be applied: + * ->regshift = 0 + * In this case IRQ must be provided, otherwise an error will be returned. + * + * When @use_defaults is false and the respective property is found + * the following values will be validated: + * - reg-io-width (->iotype) + * - reg-offset (->mapsize against ->mapbase) + * + * Returns: 0 on success or negative errno on failure + */ +int uart_read_port_properties(struct uart_port *port, bool use_defaults) +{ + struct device *dev = port->dev; + u32 value; + int ret; + + /* Read optional UART functional clock frequency */ + device_property_read_u32(dev, "clock-frequency", &port->uartclk); + + /* Read the registers alignment (default: 8-bit) */ + ret = device_property_read_u32(dev, "reg-shift", &value); + if (ret) + port->regshift = use_defaults ? 0 : port->regshift; + else + port->regshift = value; + + /* Read the registers I/O access type (default: MMIO 8-bit) */ + ret = device_property_read_u32(dev, "reg-io-width", &value); + if (ret) { + port->iotype = UPIO_MEM; + } else { + switch (value) { + case 1: + port->iotype = UPIO_MEM; + break; + case 2: + port->iotype = UPIO_MEM16; + break; + case 4: + port->iotype = device_is_big_endian(dev) ? UPIO_MEM32BE : UPIO_MEM32; + break; + default: + if (!use_defaults) { + dev_err(dev, "Unsupported reg-io-width (%u)\n", value); + return -EINVAL; + } + port->iotype = UPIO_UNKNOWN; + break; + } + } + + /* Read the address mapping base offset (default: no offset) */ + ret = device_property_read_u32(dev, "reg-offset", &value); + if (ret) + value = 0; + + /* Check for shifted address mapping overflow */ + if (!use_defaults && port->mapsize < value) { + dev_err(dev, "reg-offset %u exceeds region size %pa\n", value, &port->mapsize); + return -EINVAL; + } + + port->mapbase += value; + port->mapsize -= value; + + /* Read optional FIFO size */ + device_property_read_u32(dev, "fifo-size", &port->fifosize); + + if (device_property_read_bool(dev, "no-loopback-test")) + port->flags |= UPF_SKIP_TEST; + + /* Get index of serial line, if found in DT aliases */ + ret = of_alias_get_id(dev_of_node(dev), "serial"); + if (ret >= 0) + port->line = ret; + + if (dev_is_platform(dev)) + ret = platform_get_irq(to_platform_device(dev), 0); + else + ret = fwnode_irq_get(dev_fwnode(dev), 0); + if (ret == -EPROBE_DEFER) + return ret; + if (ret > 0) + port->irq = ret; + else if (use_defaults) + /* By default IRQ support is mandatory */ + return ret; + else + port->irq = 0; + + port->flags |= UPF_SHARE_IRQ; + + return 0; +} +EXPORT_SYMBOL(uart_read_port_properties); + static struct device_driver serial_port_driver = { .name = "port", .suppress_bind_attrs = true, diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index c2cf9484014c..3fc8683e7b53 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -962,6 +962,7 @@ int uart_register_driver(struct uart_driver *uart); void uart_unregister_driver(struct uart_driver *uart); int uart_add_one_port(struct uart_driver *reg, struct uart_port *port); void uart_remove_one_port(struct uart_driver *reg, struct uart_port *port); +int uart_read_port_properties(struct uart_port *port, bool use_defaults); bool uart_match_port(const struct uart_port *port1, const struct uart_port *port2);
Several serial drivers want to read the same or similar set of the port properties. Make a common helper for them. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> --- drivers/tty/serial/serial_port.c | 134 +++++++++++++++++++++++++++++++ include/linux/serial_core.h | 1 + 2 files changed, 135 insertions(+)