[PATCH] serial: 8250_of: Add IO space support

From: John Garry
Date: Thu Apr 19 2018 - 11:43:06 EST


Currently the 8250_of driver only supports MEM IO type
accesses.

Some development boards (Huawei D03, specifically) require
IO space access for 8250-compatible OF driver support, so
add it.

The modification is quite simple: just set the port iotype
and associated flags depending on the device address
resource type.

Signed-off-by: John Garry <john.garry@xxxxxxxxxx>

diff --git a/drivers/tty/serial/8250/8250_of.c b/drivers/tty/serial/8250/8250_of.c
index 9835b1c..a7ffaf6 100644
--- a/drivers/tty/serial/8250/8250_of.c
+++ b/drivers/tty/serial/8250/8250_of.c
@@ -92,13 +92,43 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
goto err_unprepare;
}

+ port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT |
+ UPF_FIXED_TYPE;
spin_lock_init(&port->lock);
- port->mapbase = resource.start;
- port->mapsize = resource_size(&resource);

- /* Check for shifted address mapping */
- if (of_property_read_u32(np, "reg-offset", &prop) == 0)
- port->mapbase += prop;
+ if ((resource.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_IO) {
+ port->iotype = UPIO_PORT;
+ port->iobase = resource.start;
+ } else {
+ port->mapbase = resource.start;
+ port->mapsize = resource_size(&resource);
+
+ /* Check for shifted address mapping */
+ if (of_property_read_u32(np, "reg-offset", &prop) == 0)
+ port->mapbase += prop;
+
+ port->iotype = UPIO_MEM;
+ if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
+ switch (prop) {
+ case 1:
+ port->iotype = UPIO_MEM;
+ break;
+ case 2:
+ port->iotype = UPIO_MEM16;
+ break;
+ case 4:
+ port->iotype = of_device_is_big_endian(np) ?
+ UPIO_MEM32BE : UPIO_MEM32;
+ break;
+ default:
+ dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
+ prop);
+ ret = -EINVAL;
+ goto err_dispose;
+ }
+ }
+ port->flags |= UPF_IOREMAP;
+ }

/* Check for registers offset within the devices address range */
if (of_property_read_u32(np, "reg-shift", &prop) == 0)
@@ -114,26 +144,6 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
port->line = ret;

port->irq = irq_of_parse_and_map(np, 0);
- port->iotype = UPIO_MEM;
- if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
- switch (prop) {
- case 1:
- port->iotype = UPIO_MEM;
- break;
- case 2:
- port->iotype = UPIO_MEM16;
- break;
- case 4:
- port->iotype = of_device_is_big_endian(np) ?
- UPIO_MEM32BE : UPIO_MEM32;
- break;
- default:
- dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
- prop);
- ret = -EINVAL;
- goto err_dispose;
- }
- }

info->rst = devm_reset_control_get_optional_shared(&ofdev->dev, NULL);
if (IS_ERR(info->rst)) {
@@ -147,8 +157,6 @@ static int of_platform_serial_setup(struct platform_device *ofdev,

port->type = type;
port->uartclk = clk;
- port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
- | UPF_FIXED_PORT | UPF_FIXED_TYPE;

if (of_property_read_bool(np, "no-loopback-test"))
port->flags |= UPF_SKIP_TEST;
--
1.9.1