diff options
Diffstat (limited to 'drivers/input/serio/olpc_apsp.c')
| -rw-r--r-- | drivers/input/serio/olpc_apsp.c | 272 |
1 files changed, 272 insertions, 0 deletions
diff --git a/drivers/input/serio/olpc_apsp.c b/drivers/input/serio/olpc_apsp.c new file mode 100644 index 000000000..04d2db982 --- /dev/null +++ b/drivers/input/serio/olpc_apsp.c @@ -0,0 +1,272 @@ +// 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; + struct resource *res; + int error; + + priv = devm_kzalloc(&pdev->dev, sizeof(struct olpc_apsp), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->dev = &pdev->dev; + + 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; + + /* 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; + 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(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; + 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 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); |