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Subject[PATCH resend] serial: 8250: Add support for using platform_device resources
Date
Allow getting memory resource (mapbase or iobase) as well as irq from
platform_device resources.

The UPF_DEV_RESOURCES flag must be set for devices where platform_device
resources are to be used. When not set, driver behaves as before.

This allows use of the serial8250 driver together with devices with
resources added by platform_device_add_resources(), such as mfd child
devices added with mfd_add_devices().

When UPF_DEV_RESOURCES flag is set, the following platform_data fields should
not be used: mapbase, iobase, mapsize, and irq. They are superseded by the
resources attached to the device.

Signed-off-by: Esben Haabendal <esben@geanix.com>
---
drivers/tty/serial/8250/8250_core.c | 56 +++++++++++++++++++++++++++++++++----
drivers/tty/serial/8250/8250_port.c | 15 ++++++----
include/linux/serial_core.h | 1 +
3 files changed, 62 insertions(+), 10 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index e441221..9df6a98 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -788,6 +788,48 @@ void serial8250_resume_port(int line)
}
EXPORT_SYMBOL(serial8250_resume_port);

+static int serial8250_probe_resources(struct platform_device *pdev,
+ unsigned int num,
+ struct plat_serial8250_port *p,
+ struct uart_8250_port *uart)
+{
+ struct resource *r;
+ int irq;
+
+ switch (p->iotype) {
+ case UPIO_AU:
+ case UPIO_TSI:
+ case UPIO_MEM32:
+ case UPIO_MEM32BE:
+ case UPIO_MEM16:
+ case UPIO_MEM:
+ r = platform_get_resource(pdev, IORESOURCE_MEM, num);
+ if (!r)
+ return -ENODEV;
+ uart->port.mapbase = r->start;
+ uart->port.mapsize = resource_size(r);
+ uart->port.flags |= UPF_IOREMAP;
+ break;
+ case UPIO_HUB6:
+ case UPIO_PORT:
+ r = platform_get_resource(pdev, IORESOURCE_IO, num);
+ if (!r)
+ return -ENODEV;
+ uart->port.iobase = r->start;
+ uart->port.mapsize = resource_size(r);
+ break;
+ }
+
+ irq = platform_get_irq(pdev, num);
+ if (irq == -ENXIO)
+ uart->port.irq = 0; /* no interrupt -> use polling */
+ else if (irq < 0)
+ return irq;
+ uart->port.irq = irq;
+
+ return 0;
+}
+
/*
* Register a set of serial devices attached to a platform device. The
* list is terminated with a zero flags entry, which means we expect
@@ -805,15 +847,19 @@ static int serial8250_probe(struct platform_device *dev)
irqflag = IRQF_SHARED;

for (i = 0; p && p->flags != 0; p++, i++) {
- uart.port.iobase = p->iobase;
- uart.port.membase = p->membase;
- uart.port.irq = p->irq;
+ uart.port.flags = p->flags;
+ if (p->flags & UPF_DEV_RESOURCES) {
+ serial8250_probe_resources(dev, i, p, &uart);
+ } else {
+ uart.port.iobase = p->iobase;
+ uart.port.mapbase = p->mapbase;
+ uart.port.membase = p->membase;
+ uart.port.irq = p->irq;
+ }
uart.port.irqflags = p->irqflags;
uart.port.uartclk = p->uartclk;
uart.port.regshift = p->regshift;
uart.port.iotype = p->iotype;
- uart.port.flags = p->flags;
- uart.port.mapbase = p->mapbase;
uart.port.hub6 = p->hub6;
uart.port.private_data = p->private_data;
uart.port.type = p->type;
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index d2f3310..7fa1e49 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -2863,7 +2863,8 @@ static int serial8250_request_std_resource(struct uart_8250_port *up)
if (!port->mapbase)
break;

- if (!request_mem_region(port->mapbase, size, "serial")) {
+ if (!(port->flags & UPF_DEV_RESOURCES) &&
+ !request_mem_region(port->mapbase, size, "serial")) {
ret = -EBUSY;
break;
}
@@ -2871,7 +2872,8 @@ static int serial8250_request_std_resource(struct uart_8250_port *up)
if (port->flags & UPF_IOREMAP) {
port->membase = ioremap_nocache(port->mapbase, size);
if (!port->membase) {
- release_mem_region(port->mapbase, size);
+ if (!(port->flags & UPF_DEV_RESOURCES))
+ release_mem_region(port->mapbase, size);
ret = -ENOMEM;
}
}
@@ -2879,7 +2881,8 @@ static int serial8250_request_std_resource(struct uart_8250_port *up)

case UPIO_HUB6:
case UPIO_PORT:
- if (!request_region(port->iobase, size, "serial"))
+ if (!(port->flags & UPF_DEV_RESOURCES) &&
+ !request_region(port->iobase, size, "serial"))
ret = -EBUSY;
break;
}
@@ -2906,12 +2909,14 @@ static void serial8250_release_std_resource(struct uart_8250_port *up)
port->membase = NULL;
}

- release_mem_region(port->mapbase, size);
+ if (!(port->flags & UPF_DEV_RESOURCES))
+ release_mem_region(port->mapbase, size);
break;

case UPIO_HUB6:
case UPIO_PORT:
- release_region(port->iobase, size);
+ if (!(port->flags & UPF_DEV_RESOURCES))
+ release_region(port->iobase, size);
break;
}
}
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 5fe2b03..87b4ed3 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -207,6 +207,7 @@ struct uart_port {
#define UPF_BUGGY_UART ((__force upf_t) ASYNC_BUGGY_UART /* 14 */ )
#define UPF_MAGIC_MULTIPLIER ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )

+#define UPF_DEV_RESOURCES ((__force upf_t) (1 << 18))
#define UPF_NO_THRE_TEST ((__force upf_t) (1 << 19))
/* Port has hardware-assisted h/w flow control */
#define UPF_AUTO_CTS ((__force upf_t) (1 << 20))
--
2.4.11
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