--- /dev/null
+/*
+ * 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/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);
+ 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 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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