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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* OLPC serio driver for multiplexed input from Marvell MMP security processor
*
* Copyright (C) 2011-2013 One Laptop Per Child
*/
#include <linux/module.h>
#include <linux/interrupt.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;
unsigned long l;
if (priv->open_count++ == 0) {
l = readl(priv->base + COMMAND_FIFO_STATUS);
if (!(l & CMD_STS_MASK)) {
dev_err(priv->dev, "SP cannot accept commands.\n");
return -EIO;
}
/* 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;
int error;
priv = devm_kzalloc(&pdev->dev, sizeof(struct olpc_apsp), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->dev = &pdev->dev;
priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
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;
/* KEYBOARD */
kb_serio = kzalloc(sizeof(*kb_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;
strscpy(kb_serio->name, "sp keyboard", sizeof(kb_serio->name));
strscpy(kb_serio->phys, "sp/serio0", sizeof(kb_serio->phys));
priv->kbio = kb_serio;
serio_register_port(kb_serio);
/* TOUCHPAD */
pad_serio = kzalloc(sizeof(*pad_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;
strscpy(pad_serio->name, "sp touchpad", sizeof(pad_serio->name));
strscpy(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;
}
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 void 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);
}
static const 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",
.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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