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: Daniel Drake <d...@laptop.org> --- .../devicetree/bindings/serio/olpc,ap-sp.txt | 13 + drivers/input/serio/Kconfig | 10 + drivers/input/serio/Makefile | 1 + drivers/input/serio/olpc_apsp.c | 264 +++++++++++++++++++++ 4 files changed, 288 insertions(+) create mode 100644 Documentation/devicetree/bindings/serio/olpc,ap-sp.txt create mode 100644 drivers/input/serio/olpc_apsp.c diff --git a/Documentation/devicetree/bindings/serio/olpc,ap-sp.txt b/Documentation/devicetree/bindings/serio/olpc,ap-sp.txt new file mode 100644 index 0000000..0e72183 --- /dev/null +++ b/Documentation/devicetree/bindings/serio/olpc,ap-sp.txt @@ -0,0 +1,13 @@ +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>; + } diff --git a/drivers/input/serio/Kconfig b/drivers/input/serio/Kconfig index 1bda828..94c17c2 100644 --- a/drivers/input/serio/Kconfig +++ b/drivers/input/serio/Kconfig @@ -256,4 +256,14 @@ 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 diff --git a/drivers/input/serio/Makefile b/drivers/input/serio/Makefile index 8edb36c..12298b1 100644 --- a/drivers/input/serio/Makefile +++ b/drivers/input/serio/Makefile @@ -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 diff --git a/drivers/input/serio/olpc_apsp.c b/drivers/input/serio/olpc_apsp.c new file mode 100644 index 0000000..068195c --- /dev/null +++ b/drivers/input/serio/olpc_apsp.c @@ -0,0 +1,264 @@ +/* + * 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 <asm/irq.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. + */ + +static bool apsp_debug; +module_param_named(debug, apsp_debug, bool, 0600); +MODULE_PARM_DESC(debug, "Turn debugging mode on and off"); + +#define dbg(format, arg...) \ + do { \ + if (apsp_debug) \ + pr_info(KBUILD_MODNAME ": " format, ##arg); \ + } while (0) + + +/* 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; +}; + +static int olpc_apsp_pad_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; + + dbg("olpc_apsp_pad_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; + } + msleep(1); + } + + dbg("olpc_apsp_pad_write timeout, status=%x\n", + readl(priv->base + COMMAND_FIFO_STATUS)); + return -ETIMEDOUT; +} + +static irqreturn_t olpc_input_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); + dbg("olpc_input_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_pad_open(struct serio *port) +{ + unsigned int tmp; + struct olpc_apsp *priv = port->port_data; + + /* 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 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 ret; + int irq; + + 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 (WARN_ON(!res)) + return -ENOENT; + + priv->base = devm_ioremap_resource(&pdev->dev, res); + if (WARN_ON(!priv->base)) + return -EIO; + + irq = platform_get_irq(pdev, 0); + if (WARN_ON(irq < 0)) + return irq; + + l = readl(priv->base + COMMAND_FIFO_STATUS); + if (!(l & CMD_STS_MASK)) { + dev_err(&pdev->dev, "SP cannot accept commands.\n"); + return -ENODEV; + } + + ret = devm_request_irq(&pdev->dev, irq, olpc_input_rx, 0, "olpc-apsp", + priv); + if (WARN_ON(ret)) + return ret; + + /* KEYBOARD */ + kb_serio = devm_kzalloc(&pdev->dev, sizeof(struct serio), GFP_KERNEL); + if (!kb_serio) + return -ENOMEM; + kb_serio->id.type = SERIO_8042_XL; + kb_serio->write = olpc_apsp_pad_write; + kb_serio->open = olpc_apsp_pad_open; + 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 = devm_kzalloc(&pdev->dev, sizeof(struct serio), GFP_KERNEL); + if (!pad_serio) { + serio_unregister_port(kb_serio); + return -ENOMEM; + } + pad_serio->id.type = SERIO_PS_PSTHRU; + pad_serio->write = olpc_apsp_pad_write; + pad_serio->open = olpc_apsp_pad_open; + 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); + + priv->dev = &pdev->dev; + device_init_wakeup(priv->dev, 1); + platform_set_drvdata(pdev, priv); + dev_info(&pdev->dev, "probed successfully.\n"); + return 0; +} + +static int olpc_apsp_remove(struct platform_device *pdev) +{ + struct olpc_apsp *priv = platform_get_drvdata(pdev); + 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_driver_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); -- 1.8.1.4 _______________________________________________ devicetree-discuss mailing list devicetree-discuss@lists.ozlabs.org https://lists.ozlabs.org/listinfo/devicetree-discuss