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From:   Esben Haabendal <esben@geanix.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-serial@vger.kernel.org
Cc:     Lee Jones <lee.jones@linaro.org>, Enrico Weigelt <lkml@metux.net>,
        Jiri Slaby <jslaby@suse.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Darwin Dingel <darwin.dingel@alliedtelesis.co.nz>,
        Jisheng Zhang <Jisheng.Zhang@synaptics.com>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        He Zhe <zhe.he@windriver.com>, Marek Vasut <marex@denx.de>,
        Douglas Anderson <dianders@chromium.org>,
        Paul Burton <paul.burton@mips.com>,
        linux-kernel@vger.kernel.org
Subject: [PATCH resend] serial: 8250: Add support for using platform_device resources
Date:   Tue, 21 May 2019 13:34:26 +0200
Message-Id: <20190521113426.16790-1-esben@geanix.com>
In-Reply-To: <20190430140416.4707-1-esben@geanix.com>
References: <20190430140416.4707-1-esben@geanix.com>
MIME-Version: 1.0
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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  They are superseded by the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