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272 lines
7.0 KiB
272 lines
7.0 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* OLPC serio driver for multiplexed input from Marvell MMP security processor |
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* |
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* Copyright (C) 2011-2013 One Laptop Per Child |
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*/ |
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#include <linux/module.h> |
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#include <linux/interrupt.h> |
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#include <linux/serio.h> |
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#include <linux/err.h> |
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#include <linux/platform_device.h> |
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#include <linux/io.h> |
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#include <linux/of.h> |
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#include <linux/slab.h> |
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#include <linux/delay.h> |
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/* |
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* The OLPC XO-1.75 and XO-4 laptops do not have a hardware PS/2 controller. |
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* Instead, the OLPC firmware runs a bit-banging PS/2 implementation on an |
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* otherwise-unused slow processor which is included in the Marvell MMP2/MMP3 |
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* SoC, known as the "Security Processor" (SP) or "Wireless Trusted Module" |
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* (WTM). This firmware then reports its results via the WTM registers, |
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* which we read from the Application Processor (AP, i.e. main CPU) in this |
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* driver. |
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* |
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* On the hardware side we have a PS/2 mouse and an AT keyboard, the data |
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* is multiplexed through this system. We create a serio port for each one, |
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* and demultiplex the data accordingly. |
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*/ |
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/* WTM register offsets */ |
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#define SECURE_PROCESSOR_COMMAND 0x40 |
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#define COMMAND_RETURN_STATUS 0x80 |
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#define COMMAND_FIFO_STATUS 0xc4 |
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#define PJ_RST_INTERRUPT 0xc8 |
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#define PJ_INTERRUPT_MASK 0xcc |
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/* |
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* The upper byte of SECURE_PROCESSOR_COMMAND and COMMAND_RETURN_STATUS is |
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* used to identify which port (device) is being talked to. The lower byte |
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* is the data being sent/received. |
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*/ |
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#define PORT_MASK 0xff00 |
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#define DATA_MASK 0x00ff |
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#define PORT_SHIFT 8 |
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#define KEYBOARD_PORT 0 |
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#define TOUCHPAD_PORT 1 |
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/* COMMAND_FIFO_STATUS */ |
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#define CMD_CNTR_MASK 0x7 /* Number of pending/unprocessed commands */ |
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#define MAX_PENDING_CMDS 4 /* from device specs */ |
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/* PJ_RST_INTERRUPT */ |
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#define SP_COMMAND_COMPLETE_RESET 0x1 |
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/* PJ_INTERRUPT_MASK */ |
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#define INT_0 (1 << 0) |
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/* COMMAND_FIFO_STATUS */ |
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#define CMD_STS_MASK 0x100 |
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struct olpc_apsp { |
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struct device *dev; |
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struct serio *kbio; |
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struct serio *padio; |
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void __iomem *base; |
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int open_count; |
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int irq; |
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}; |
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static int olpc_apsp_write(struct serio *port, unsigned char val) |
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{ |
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struct olpc_apsp *priv = port->port_data; |
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unsigned int i; |
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u32 which = 0; |
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if (port == priv->padio) |
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which = TOUCHPAD_PORT << PORT_SHIFT; |
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else |
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which = KEYBOARD_PORT << PORT_SHIFT; |
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dev_dbg(priv->dev, "olpc_apsp_write which=%x val=%x\n", which, val); |
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for (i = 0; i < 50; i++) { |
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u32 sts = readl(priv->base + COMMAND_FIFO_STATUS); |
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if ((sts & CMD_CNTR_MASK) < MAX_PENDING_CMDS) { |
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writel(which | val, |
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priv->base + SECURE_PROCESSOR_COMMAND); |
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return 0; |
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} |
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/* SP busy. This has not been seen in practice. */ |
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mdelay(1); |
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} |
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dev_dbg(priv->dev, "olpc_apsp_write timeout, status=%x\n", |
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readl(priv->base + COMMAND_FIFO_STATUS)); |
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return -ETIMEDOUT; |
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} |
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static irqreturn_t olpc_apsp_rx(int irq, void *dev_id) |
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{ |
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struct olpc_apsp *priv = dev_id; |
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unsigned int w, tmp; |
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struct serio *serio; |
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/* |
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* Write 1 to PJ_RST_INTERRUPT to acknowledge and clear the interrupt |
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* Write 0xff00 to SECURE_PROCESSOR_COMMAND. |
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*/ |
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tmp = readl(priv->base + PJ_RST_INTERRUPT); |
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if (!(tmp & SP_COMMAND_COMPLETE_RESET)) { |
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dev_warn(priv->dev, "spurious interrupt?\n"); |
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return IRQ_NONE; |
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} |
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w = readl(priv->base + COMMAND_RETURN_STATUS); |
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dev_dbg(priv->dev, "olpc_apsp_rx %x\n", w); |
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if (w >> PORT_SHIFT == KEYBOARD_PORT) |
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serio = priv->kbio; |
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else |
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serio = priv->padio; |
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serio_interrupt(serio, w & DATA_MASK, 0); |
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/* Ack and clear interrupt */ |
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writel(tmp | SP_COMMAND_COMPLETE_RESET, priv->base + PJ_RST_INTERRUPT); |
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writel(PORT_MASK, priv->base + SECURE_PROCESSOR_COMMAND); |
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pm_wakeup_event(priv->dev, 1000); |
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return IRQ_HANDLED; |
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} |
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static int olpc_apsp_open(struct serio *port) |
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{ |
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struct olpc_apsp *priv = port->port_data; |
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unsigned int tmp; |
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unsigned long l; |
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if (priv->open_count++ == 0) { |
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l = readl(priv->base + COMMAND_FIFO_STATUS); |
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if (!(l & CMD_STS_MASK)) { |
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dev_err(priv->dev, "SP cannot accept commands.\n"); |
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return -EIO; |
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} |
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/* Enable interrupt 0 by clearing its bit */ |
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tmp = readl(priv->base + PJ_INTERRUPT_MASK); |
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writel(tmp & ~INT_0, priv->base + PJ_INTERRUPT_MASK); |
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} |
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return 0; |
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} |
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static void olpc_apsp_close(struct serio *port) |
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{ |
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struct olpc_apsp *priv = port->port_data; |
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unsigned int tmp; |
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if (--priv->open_count == 0) { |
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/* Disable interrupt 0 */ |
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tmp = readl(priv->base + PJ_INTERRUPT_MASK); |
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writel(tmp | INT_0, priv->base + PJ_INTERRUPT_MASK); |
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} |
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} |
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static int olpc_apsp_probe(struct platform_device *pdev) |
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{ |
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struct serio *kb_serio, *pad_serio; |
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struct olpc_apsp *priv; |
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struct resource *res; |
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int error; |
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priv = devm_kzalloc(&pdev->dev, sizeof(struct olpc_apsp), GFP_KERNEL); |
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if (!priv) |
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return -ENOMEM; |
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priv->dev = &pdev->dev; |
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
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priv->base = devm_ioremap_resource(&pdev->dev, res); |
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if (IS_ERR(priv->base)) { |
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dev_err(&pdev->dev, "Failed to map WTM registers\n"); |
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return PTR_ERR(priv->base); |
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} |
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priv->irq = platform_get_irq(pdev, 0); |
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if (priv->irq < 0) |
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return priv->irq; |
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/* KEYBOARD */ |
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kb_serio = kzalloc(sizeof(struct serio), GFP_KERNEL); |
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if (!kb_serio) |
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return -ENOMEM; |
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kb_serio->id.type = SERIO_8042_XL; |
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kb_serio->write = olpc_apsp_write; |
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kb_serio->open = olpc_apsp_open; |
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kb_serio->close = olpc_apsp_close; |
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kb_serio->port_data = priv; |
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kb_serio->dev.parent = &pdev->dev; |
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strlcpy(kb_serio->name, "sp keyboard", sizeof(kb_serio->name)); |
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strlcpy(kb_serio->phys, "sp/serio0", sizeof(kb_serio->phys)); |
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priv->kbio = kb_serio; |
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serio_register_port(kb_serio); |
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/* TOUCHPAD */ |
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pad_serio = kzalloc(sizeof(struct serio), GFP_KERNEL); |
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if (!pad_serio) { |
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error = -ENOMEM; |
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goto err_pad; |
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} |
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pad_serio->id.type = SERIO_8042; |
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pad_serio->write = olpc_apsp_write; |
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pad_serio->open = olpc_apsp_open; |
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pad_serio->close = olpc_apsp_close; |
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pad_serio->port_data = priv; |
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pad_serio->dev.parent = &pdev->dev; |
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strlcpy(pad_serio->name, "sp touchpad", sizeof(pad_serio->name)); |
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strlcpy(pad_serio->phys, "sp/serio1", sizeof(pad_serio->phys)); |
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priv->padio = pad_serio; |
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serio_register_port(pad_serio); |
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error = request_irq(priv->irq, olpc_apsp_rx, 0, "olpc-apsp", priv); |
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if (error) { |
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dev_err(&pdev->dev, "Failed to request IRQ\n"); |
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goto err_irq; |
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} |
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device_init_wakeup(priv->dev, 1); |
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platform_set_drvdata(pdev, priv); |
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dev_dbg(&pdev->dev, "probed successfully.\n"); |
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return 0; |
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err_irq: |
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serio_unregister_port(pad_serio); |
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err_pad: |
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serio_unregister_port(kb_serio); |
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return error; |
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} |
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static int olpc_apsp_remove(struct platform_device *pdev) |
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{ |
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struct olpc_apsp *priv = platform_get_drvdata(pdev); |
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free_irq(priv->irq, priv); |
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serio_unregister_port(priv->kbio); |
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serio_unregister_port(priv->padio); |
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return 0; |
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} |
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static const struct of_device_id olpc_apsp_dt_ids[] = { |
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{ .compatible = "olpc,ap-sp", }, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(of, olpc_apsp_dt_ids); |
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static struct platform_driver olpc_apsp_driver = { |
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.probe = olpc_apsp_probe, |
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.remove = olpc_apsp_remove, |
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.driver = { |
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.name = "olpc-apsp", |
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.of_match_table = olpc_apsp_dt_ids, |
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}, |
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}; |
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MODULE_DESCRIPTION("OLPC AP-SP serio driver"); |
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MODULE_LICENSE("GPL"); |
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module_platform_driver(olpc_apsp_driver);
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