Commit b56ece9a authored by Daniel Drake's avatar Daniel Drake Committed by Dmitry Torokhov
Browse files

Input: add OLPC AP-SP driver 



The OLPC XO-1.75 and XO-4 laptops include a PS/2 touchpad and an AT
keyboard, yet they do not have a hardware PS/2 controller. Instead, a
firmware runs on a dedicated core ("Security Processor", part of the SoC)
that acts as a PS/2 controller through bit-banging.

Communication between the main cpu (Application Processor) and the
Security Processor happens via a standard command mechanism implemented
by the SoC. Add a driver for this interface to enable keyboard/mouse
input on this platform.

Original author: Saadia Baloch
Signed-off-by: default avatarDaniel Drake <dsd@laptop.org>
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent 20c3da9f

Documentation/devicetree/bindings/serio/olpc,ap-sp.txt

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OLPC AP-SP serio interface



Required properties:

- compatible : "olpc,ap-sp"

- reg : base address and length of SoC's WTM registers

- interrupts : SP-AP interrupt



Example:

	ap-sp@d4290000 {

		compatible = "olpc,ap-sp";

		reg = <0xd4290000 0x1000>;

		interrupts = <40>;

	}

drivers/input/serio/Kconfig

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@@ -255,4 +255,14 @@ config SERIO_APBPS2 
	  To compile this driver as a module, choose M here: the module will

	  be called apbps2.



config SERIO_OLPC_APSP

	tristate "OLPC AP-SP input support"

	depends on OF

	help

	  Say Y here if you want support for the keyboard and touchpad included

	  in the OLPC XO-1.75 and XO-4 laptops.



	  To compile this driver as a module, choose M here: the module will

	  be called olpc_apsp.



endif

drivers/input/serio/Makefile

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@@ -27,3 +27,4 @@ obj-$(CONFIG_SERIO_XILINX_XPS_PS2) += xilinx_ps2.o 
obj-$(CONFIG_SERIO_ALTERA_PS2)	+= altera_ps2.o

obj-$(CONFIG_SERIO_ARC_PS2)	+= arc_ps2.o

obj-$(CONFIG_SERIO_APBPS2)	+= apbps2.o

obj-$(CONFIG_SERIO_OLPC_APSP)	+= olpc_apsp.o

drivers/input/serio/olpc_apsp.c

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/*

 * OLPC serio driver for multiplexed input from Marvell MMP security processor

 *

 * Copyright (C) 2011-2013 One Laptop Per Child

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */



#include <linux/module.h>

#include <linux/interrupt.h>

#include <linux/init.h>

#include <linux/serio.h>

#include <linux/err.h>

#include <linux/platform_device.h>

#include <linux/io.h>

#include <linux/of.h>

#include <linux/slab.h>

#include <linux/delay.h>



/*

 * The OLPC XO-1.75 and XO-4 laptops do not have a hardware PS/2 controller.

 * Instead, the OLPC firmware runs a bit-banging PS/2 implementation on an

 * otherwise-unused slow processor which is included in the Marvell MMP2/MMP3

 * SoC, known as the "Security Processor" (SP) or "Wireless Trusted Module"

 * (WTM). This firmware then reports its results via the WTM registers,

 * which we read from the Application Processor (AP, i.e. main CPU) in this

 * driver.

 *

 * On the hardware side we have a PS/2 mouse and an AT keyboard, the data

 * is multiplexed through this system. We create a serio port for each one,

 * and demultiplex the data accordingly.

 */



/* WTM register offsets */

#define SECURE_PROCESSOR_COMMAND	0x40

#define COMMAND_RETURN_STATUS		0x80

#define COMMAND_FIFO_STATUS		0xc4

#define PJ_RST_INTERRUPT		0xc8

#define PJ_INTERRUPT_MASK		0xcc



/*

 * The upper byte of SECURE_PROCESSOR_COMMAND and COMMAND_RETURN_STATUS is

 * used to identify which port (device) is being talked to. The lower byte

 * is the data being sent/received.

 */

#define PORT_MASK	0xff00

#define DATA_MASK	0x00ff

#define PORT_SHIFT	8

#define KEYBOARD_PORT	0

#define TOUCHPAD_PORT	1



/* COMMAND_FIFO_STATUS */

#define CMD_CNTR_MASK		0x7 /* Number of pending/unprocessed commands */

#define MAX_PENDING_CMDS	4   /* from device specs */



/* PJ_RST_INTERRUPT */

#define SP_COMMAND_COMPLETE_RESET	0x1



/* PJ_INTERRUPT_MASK */

#define INT_0	(1 << 0)



/* COMMAND_FIFO_STATUS */

#define CMD_STS_MASK	0x100



struct olpc_apsp {

	struct device *dev;

	struct serio *kbio;

	struct serio *padio;

	void __iomem *base;

	int open_count;

	int irq;

};



static int olpc_apsp_write(struct serio *port, unsigned char val)

{

	struct olpc_apsp *priv = port->port_data;

	unsigned int i;

	u32 which = 0;



	if (port == priv->padio)

		which = TOUCHPAD_PORT << PORT_SHIFT;

	else

		which = KEYBOARD_PORT << PORT_SHIFT;



	dev_dbg(priv->dev, "olpc_apsp_write which=%x val=%x\n", which, val);

	for (i = 0; i < 50; i++) {

		u32 sts = readl(priv->base + COMMAND_FIFO_STATUS);

		if ((sts & CMD_CNTR_MASK) < MAX_PENDING_CMDS) {

			writel(which | val,

			       priv->base + SECURE_PROCESSOR_COMMAND);

			return 0;

		}

		/* SP busy. This has not been seen in practice. */

		mdelay(1);

	}



	dev_dbg(priv->dev, "olpc_apsp_write timeout, status=%x\n",

		readl(priv->base + COMMAND_FIFO_STATUS));



	return -ETIMEDOUT;

}



static irqreturn_t olpc_apsp_rx(int irq, void *dev_id)

{

	struct olpc_apsp *priv = dev_id;

	unsigned int w, tmp;

	struct serio *serio;



	/*

	 * Write 1 to PJ_RST_INTERRUPT to acknowledge and clear the interrupt

	 * Write 0xff00 to SECURE_PROCESSOR_COMMAND.

	 */

	tmp = readl(priv->base + PJ_RST_INTERRUPT);

	if (!(tmp & SP_COMMAND_COMPLETE_RESET)) {

		dev_warn(priv->dev, "spurious interrupt?\n");

		return IRQ_NONE;

	}



	w = readl(priv->base + COMMAND_RETURN_STATUS);

	dev_dbg(priv->dev, "olpc_apsp_rx %x\n", w);



	if (w >> PORT_SHIFT == KEYBOARD_PORT)

		serio = priv->kbio;

	else

		serio = priv->padio;



	serio_interrupt(serio, w & DATA_MASK, 0);



	/* Ack and clear interrupt */

	writel(tmp | SP_COMMAND_COMPLETE_RESET, priv->base + PJ_RST_INTERRUPT);

	writel(PORT_MASK, priv->base + SECURE_PROCESSOR_COMMAND);



	pm_wakeup_event(priv->dev, 1000);

	return IRQ_HANDLED;

}



static int olpc_apsp_open(struct serio *port)

{

	struct olpc_apsp *priv = port->port_data;

	unsigned int tmp;



	if (priv->open_count++ == 0) {

		/* Enable interrupt 0 by clearing its bit */

		tmp = readl(priv->base + PJ_INTERRUPT_MASK);

		writel(tmp & ~INT_0, priv->base + PJ_INTERRUPT_MASK);

	}



	return 0;

}



static void olpc_apsp_close(struct serio *port)

{

	struct olpc_apsp *priv = port->port_data;

	unsigned int tmp;



	if (--priv->open_count == 0) {

		/* Disable interrupt 0 */

		tmp = readl(priv->base + PJ_INTERRUPT_MASK);

		writel(tmp | INT_0, priv->base + PJ_INTERRUPT_MASK);

	}

}



static int olpc_apsp_probe(struct platform_device *pdev)

{

	struct serio *kb_serio, *pad_serio;

	struct olpc_apsp *priv;

	struct resource *res;

	struct device_node *np;

	unsigned long l;

	int error;



	priv = devm_kzalloc(&pdev->dev, sizeof(struct olpc_apsp), GFP_KERNEL);

	if (!priv)

		return -ENOMEM;



	np = pdev->dev.of_node;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	if (!res)

		return -ENOENT;



	priv->base = devm_ioremap_resource(&pdev->dev, res);

	if (IS_ERR(priv->base)) {

		dev_err(&pdev->dev, "Failed to map WTM registers\n");

		return PTR_ERR(priv->base);

	}



	priv->irq = platform_get_irq(pdev, 0);

	if (priv->irq < 0)

		return priv->irq;



	l = readl(priv->base + COMMAND_FIFO_STATUS);

	if (!(l & CMD_STS_MASK)) {

		dev_err(&pdev->dev, "SP cannot accept commands.\n");

		return -EIO;

	}



	/* KEYBOARD */

	kb_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);

	if (!kb_serio)

		return -ENOMEM;

	kb_serio->id.type	= SERIO_8042_XL;

	kb_serio->write		= olpc_apsp_write;

	kb_serio->open		= olpc_apsp_open;

	kb_serio->close		= olpc_apsp_close;

	kb_serio->port_data	= priv;

	kb_serio->dev.parent	= &pdev->dev;

	strlcpy(kb_serio->name, "sp keyboard", sizeof(kb_serio->name));

	strlcpy(kb_serio->phys, "sp/serio0", sizeof(kb_serio->phys));

	priv->kbio		= kb_serio;

	serio_register_port(kb_serio);



	/* TOUCHPAD */

	pad_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);

	if (!pad_serio) {

		error = -ENOMEM;

		goto err_pad;

	}

	pad_serio->id.type	= SERIO_8042;

	pad_serio->write	= olpc_apsp_write;

	pad_serio->open		= olpc_apsp_open;

	pad_serio->close	= olpc_apsp_close;

	pad_serio->port_data	= priv;

	pad_serio->dev.parent	= &pdev->dev;

	strlcpy(pad_serio->name, "sp touchpad", sizeof(pad_serio->name));

	strlcpy(pad_serio->phys, "sp/serio1", sizeof(pad_serio->phys));

	priv->padio		= pad_serio;

	serio_register_port(pad_serio);



	error = request_irq(priv->irq, olpc_apsp_rx, 0, "olpc-apsp", priv);

	if (error) {

		dev_err(&pdev->dev, "Failed to request IRQ\n");

		goto err_irq;

	}



	priv->dev = &pdev->dev;

	device_init_wakeup(priv->dev, 1);

	platform_set_drvdata(pdev, priv);



	dev_dbg(&pdev->dev, "probed successfully.\n");

	return 0;



err_irq:

	serio_unregister_port(pad_serio);

err_pad:

	serio_unregister_port(kb_serio);

	return error;

}



static int olpc_apsp_remove(struct platform_device *pdev)

{

	struct olpc_apsp *priv = platform_get_drvdata(pdev);



	free_irq(priv->irq, priv);



	serio_unregister_port(priv->kbio);

	serio_unregister_port(priv->padio);



	return 0;

}



static struct of_device_id olpc_apsp_dt_ids[] = {

	{ .compatible = "olpc,ap-sp", },

	{}

};

MODULE_DEVICE_TABLE(of, olpc_apsp_dt_ids);



static struct platform_driver olpc_apsp_driver = {

	.probe		= olpc_apsp_probe,

	.remove		= olpc_apsp_remove,

	.driver		= {

		.name	= "olpc-apsp",

		.owner	= THIS_MODULE,

		.of_match_table = olpc_apsp_dt_ids,

	},

};



MODULE_DESCRIPTION("OLPC AP-SP serio driver");

MODULE_LICENSE("GPL");

module_platform_driver(olpc_apsp_driver);

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