[RFC PATCH 1/2] serial: 8250_dw: add IO space support

John Garry
2018-02-22T17:50:08Z

The current 8250_dw driver only supports MEM iotype. It is desired
to have a platform device-based 8250 UART driver for ACPI FW
with IO port iotype, so update the driver to support this.

Note: a solution needs to be found for autconfig
using MEM accessors only.

Signed-off-by: John Garry <john.garry@huawei.com>
---
drivers/tty/serial/8250/8250_dw.c | 25 +++++++++++++++++--------
1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index cd1b94a..28fbc8f 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -405,7 +405,7 @@ static void dw8250_setup_port(struct uart_port *p)
static int dw8250_probe(struct platform_device *pdev)
{
struct uart_8250_port uart = {};
- struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ struct resource *regs;
int irq = platform_get_irq(pdev, 0);
struct uart_port *p = &uart.port;
struct device *dev = &pdev->dev;
@@ -413,6 +413,9 @@ static int dw8250_probe(struct platform_device *pdev)
int err;
u32 val;

+ regs = platform_get_resource(pdev, IORESOURCE_MEM, 0) ?:
+ platform_get_resource(pdev, IORESOURCE_IO, 0);
+
if (!regs) {
dev_err(dev, "no registers defined\n");
return -EINVAL;
@@ -425,22 +428,28 @@ static int dw8250_probe(struct platform_device *pdev)
}

spin_lock_init(&p->lock);
- p->mapbase = regs->start;
p->irq = irq;
p->handle_irq = dw8250_handle_irq;
p->pm = dw8250_do_pm;
p->type = PORT_8250;
p->flags = UPF_SHARE_IRQ | UPF_FIXED_PORT;
p->dev = dev;
- p->iotype = UPIO_MEM;
- p->serial_in = dw8250_serial_in;
- p->serial_out = dw8250_serial_out;
p->set_ldisc = dw8250_set_ldisc;
p->set_termios = dw8250_set_termios;

- p->membase = devm_ioremap(dev, regs->start, resource_size(regs));
- if (!p->membase)
- return -ENOMEM;
+ if ((regs->flags & IORESOURCE_TYPE_BITS) == IORESOURCE_MEM) {
+ p->mapbase = regs->start;
+ p->membase = devm_ioremap(dev, regs->start,
+ resource_size(regs));
+ if (!p->membase)
+ return -ENOMEM;
+ p->iotype = UPIO_MEM;
+ p->serial_in = dw8250_serial_in;
+ p->serial_out = dw8250_serial_out;
+ } else {
+ p->iobase = regs->start;
+ p->iotype = UPIO_PORT;
+ }

data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
--
1.9.1