mfd: ioc3: Add driver for SGI IOC3 chip

SGI IOC3 chip has integrated ethernet, keyboard and mouse interface.
It also supports connecting a SuperIO chip for serial and parallel
interfaces. IOC3 is used inside various SGI systemboards and add-on
cards with different equipped external interfaces.

Support for ethernet and serial interfaces were implemented inside
the network driver. This patchset moves out the not network related
parts to a new MFD driver, which takes care of card detection,
setup of platform devices and interrupt distribution for the subdevices.

Serial portion: Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>
Network part: Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Network part: Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>

Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-serial@vger.kernel.org

3 files changed, 110 insertions, 0 deletions

diff --git a/drivers/tty/serial/8250/8250_ioc3.c b/drivers/tty/serial/8250/8250_ioc3.c
new file mode 100644
index 000000000000..4c405f1b9c67
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_ioc3.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SGI IOC3 8250 UART driver
+ *
+ * Copyright (C) 2019 Thomas Bogendoerfer <tbogendoerfer@suse.de>
+ *
+ * based on code Copyright (C) 2005 Stanislaw Skowronek <skylark@unaligned.org>
+ *               Copyright (C) 2014 Joshua Kinard <kumba@gentoo.org>
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+
+#include "8250.h"
+
+#define IOC3_UARTCLK (22000000 / 3)
+
+struct ioc3_8250_data {
+	int line;
+};
+
+static unsigned int ioc3_serial_in(struct uart_port *p, int offset)
+{
+	return readb(p->membase + (offset ^ 3));
+}
+
+static void ioc3_serial_out(struct uart_port *p, int offset, int value)
+{
+	writeb(value, p->membase + (offset ^ 3));
+}
+
+static int serial8250_ioc3_probe(struct platform_device *pdev)
+{
+	struct ioc3_8250_data *data;
+	struct uart_8250_port up;
+	struct resource *r;
+	void __iomem *membase;
+	int irq, line;
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!r)
+		return -ENODEV;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	membase = devm_ioremap_nocache(&pdev->dev, r->start, resource_size(r));
+	if (!membase)
+		return -ENOMEM;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		irq = 0; /* no interrupt -> use polling */
+
+	/* Register serial ports with 8250.c */
+	memset(&up, 0, sizeof(struct uart_8250_port));
+	up.port.iotype = UPIO_MEM;
+	up.port.uartclk = IOC3_UARTCLK;
+	up.port.type = PORT_16550A;
+	up.port.irq = irq;
+	up.port.flags = (UPF_BOOT_AUTOCONF | UPF_SHARE_IRQ);
+	up.port.dev = &pdev->dev;
+	up.port.membase = membase;
+	up.port.mapbase = r->start;
+	up.port.serial_in = ioc3_serial_in;
+	up.port.serial_out = ioc3_serial_out;
+	line = serial8250_register_8250_port(&up);
+	if (line < 0)
+		return line;
+
+	platform_set_drvdata(pdev, data);
+	return 0;
+}
+
+static int serial8250_ioc3_remove(struct platform_device *pdev)
+{
+	struct ioc3_8250_data *data = platform_get_drvdata(pdev);
+
+	serial8250_unregister_port(data->line);
+	return 0;
+}
+
+static struct platform_driver serial8250_ioc3_driver = {
+	.probe  = serial8250_ioc3_probe,
+	.remove = serial8250_ioc3_remove,
+	.driver = {
+		.name = "ioc3-serial8250",
+	}
+};
+
+module_platform_driver(serial8250_ioc3_driver);
+
+MODULE_AUTHOR("Thomas Bogendoerfer <tbogendoerfer@suse.de>");
+MODULE_DESCRIPTION("SGI IOC3 8250 UART driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index fab3d4f20667..af69a5d4ba48 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -371,6 +371,17 @@ config SERIAL_8250_EM
 	  port hardware found on the Emma Mobile line of processors.
 	  If unsure, say N.
 
+config SERIAL_8250_IOC3
+	tristate "SGI IOC3 8250 UART support"
+	depends on SGI_MFD_IOC3 && SERIAL_8250
+	select SERIAL_8250_EXTENDED
+	select SERIAL_8250_SHARE_IRQ
+	help
+	  Enable this if you have a SGI Origin or Octane machine. This module
+	  provides basic serial support by directly driving the UART chip
+	  behind the IOC3 device on those systems.  Maximum baud speed is
+	  38400bps using this driver.
+
 config SERIAL_8250_RT288X
 	bool "Ralink RT288x/RT305x/RT3662/RT3883 serial port support"
 	depends on SERIAL_8250
diff --git a/drivers/tty/serial/8250/Makefile b/drivers/tty/serial/8250/Makefile
index 08c1d8117506..51a6079d3f1f 100644
--- a/drivers/tty/serial/8250/Makefile
+++ b/drivers/tty/serial/8250/Makefile
@@ -28,6 +28,7 @@ obj-$(CONFIG_SERIAL_8250_FSL)		+= 8250_fsl.o
 obj-$(CONFIG_SERIAL_8250_MEN_MCB)	+= 8250_men_mcb.o
 obj-$(CONFIG_SERIAL_8250_DW)		+= 8250_dw.o
 obj-$(CONFIG_SERIAL_8250_EM)		+= 8250_em.o
+obj-$(CONFIG_SERIAL_8250_IOC3)		+= 8250_ioc3.o
 obj-$(CONFIG_SERIAL_8250_OMAP)		+= 8250_omap.o
 obj-$(CONFIG_SERIAL_8250_LPC18XX)	+= 8250_lpc18xx.o
 obj-$(CONFIG_SERIAL_8250_MT6577)	+= 8250_mtk.o