// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Xilinx XPS PS/2 device driver
*
* (c) 2005 MontaVista Software, Inc.
* (c) 2008 Xilinx, Inc.
*/
#include <linux/module.h>
#include <linux/serio.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/io.h>
#include <linux/mod_devicetable.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#define DRIVER_NAME "xilinx_ps2"
/* Register offsets for the xps2 device */
#define XPS2_SRST_OFFSET 0x00000000 /* Software Reset register */
#define XPS2_STATUS_OFFSET 0x00000004 /* Status register */
#define XPS2_RX_DATA_OFFSET 0x00000008 /* Receive Data register */
#define XPS2_TX_DATA_OFFSET 0x0000000C /* Transmit Data register */
#define XPS2_GIER_OFFSET 0x0000002C /* Global Interrupt Enable reg */
#define XPS2_IPISR_OFFSET 0x00000030 /* Interrupt Status register */
#define XPS2_IPIER_OFFSET 0x00000038 /* Interrupt Enable register */
/* Reset Register Bit Definitions */
#define XPS2_SRST_RESET 0x0000000A /* Software Reset */
/* Status Register Bit Positions */
#define XPS2_STATUS_RX_FULL 0x00000001 /* Receive Full */
#define XPS2_STATUS_TX_FULL 0x00000002 /* Transmit Full */
/*
* Bit definitions for ISR/IER registers. Both the registers have the same bit
* definitions and are only defined once.
*/
#define XPS2_IPIXR_WDT_TOUT 0x00000001 /* Watchdog Timeout Interrupt */
#define XPS2_IPIXR_TX_NOACK 0x00000002 /* Transmit No ACK Interrupt */
#define XPS2_IPIXR_TX_ACK 0x00000004 /* Transmit ACK (Data) Interrupt */
#define XPS2_IPIXR_RX_OVF 0x00000008 /* Receive Overflow Interrupt */
#define XPS2_IPIXR_RX_ERR 0x00000010 /* Receive Error Interrupt */
#define XPS2_IPIXR_RX_FULL 0x00000020 /* Receive Data Interrupt */
/* Mask for all the Transmit Interrupts */
#define XPS2_IPIXR_TX_ALL (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK)
/* Mask for all the Receive Interrupts */
#define XPS2_IPIXR_RX_ALL (XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR | \
XPS2_IPIXR_RX_FULL)
/* Mask for all the Interrupts */
#define XPS2_IPIXR_ALL (XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL | \
XPS2_IPIXR_WDT_TOUT)
/* Global Interrupt Enable mask */
#define XPS2_GIER_GIE_MASK 0x80000000
struct xps2data {
int irq;
spinlock_t lock;
void __iomem *base_address; /* virt. address of control registers */
unsigned int flags;
struct serio *serio; /* serio */
struct device *dev;
};
/************************************/
/* XPS PS/2 data transmission calls */
/************************************/
/**
* xps2_recv() - attempts to receive a byte from the PS/2 port.
* @drvdata: pointer to ps2 device private data structure
* @byte: address where the read data will be copied
*
* If there is any data available in the PS/2 receiver, this functions reads
* the data, otherwise it returns error.
*/
static int xps2_recv(struct xps2data *drvdata, u8 *byte)
{
u32 sr;
int status = -1;
/* If there is data available in the PS/2 receiver, read it */
sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
if (sr & XPS2_STATUS_RX_FULL) {
*byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
status = 0;
}
return status;
}
/*********************/
/* Interrupt handler */
/*********************/
static irqreturn_t xps2_interrupt(int irq, void *dev_id)
{
struct xps2data *drvdata = dev_id;
u32 intr_sr;
u8 c;
int status;
/* Get the PS/2 interrupts and clear them */
intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);
/* Check which interrupt is active */
if (intr_sr & XPS2_IPIXR_RX_OVF)
dev_warn(drvdata->dev, "receive overrun error\n");
if (intr_sr & XPS2_IPIXR_RX_ERR)
drvdata->flags |= SERIO_PARITY;
if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
drvdata->flags |= SERIO_TIMEOUT;
if (intr_sr & XPS2_IPIXR_RX_FULL) {
status = xps2_recv(drvdata, &c);
/* Error, if a byte is not received */
if (status) {
dev_err(drvdata->dev,
"wrong rcvd byte count (%d)\n", status);
} else {
serio_interrupt(drvdata->serio, c, drvdata->flags);
drvdata->flags = 0;
}
}
return IRQ_HANDLED;
}
/*******************/
/* serio callbacks */
/*******************/
/**
* sxps2_write() - sends a byte out through the PS/2 port.
* @pserio: pointer to the serio structure of the PS/2 port
* @c: data that needs to be written to the PS/2 port
*
* This function checks if the PS/2 transmitter is empty and sends a byte.
* Otherwise it returns error. Transmission fails only when nothing is connected
* to the PS/2 port. Thats why, we do not try to resend the data in case of a
* failure.
*/
static int sxps2_write(struct serio *pserio, unsigned char c)
{
struct xps2data *drvdata = pserio->port_data;
unsigned long flags;
u32 sr;
int status = -1;
spin_lock_irqsave(&drvdata->lock, flags);
/* If the PS/2 transmitter is empty send a byte of data */
sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
if (!(sr & XPS2_STATUS_TX_FULL)) {
out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
status = 0;
}
spin_unlock_irqrestore(&drvdata->lock, flags);
return status;
}
/**
* sxps2_open() - called when a port is opened by the higher layer.
* @pserio: pointer to the serio structure of the PS/2 device
*
* This function requests irq and enables interrupts for the PS/2 device.
*/
static int sxps2_open(struct serio *pserio)
{
struct xps2data *drvdata = pserio->port_data;
int error;
u8 c;
error = request_irq(drvdata->irq, &xps2_interrupt, 0,
DRIVER_NAME, drvdata);
if (error) {
dev_err(drvdata->dev,
"Couldn't allocate interrupt %d\n", drvdata->irq);
return error;
}
/* start reception by enabling the interrupts */
out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
(void)xps2_recv(drvdata, &c);
return 0; /* success */
}
/**
* sxps2_close() - frees the interrupt.
* @pserio: pointer to the serio structure of the PS/2 device
*
* This function frees the irq and disables interrupts for the PS/2 device.
*/
static void sxps2_close(struct serio *pserio)
{
struct xps2data *drvdata = pserio->port_data;
/* Disable the PS2 interrupts */
out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
free_irq(drvdata->irq, drvdata);
}
/**
* xps2_of_probe - probe method for the PS/2 device.
* @ofdev: pointer to OF device structure
*
* This function probes the PS/2 device in the device tree.
* It initializes the driver data structure and the hardware.
* It returns 0, if the driver is bound to the PS/2 device, or a negative
* value if there is an error.
*/
static int xps2_of_probe(struct platform_device *ofdev)
{
struct resource r_mem; /* IO mem resources */
struct xps2data *drvdata;
struct serio *serio;
struct device *dev = &ofdev->dev;
resource_size_t remap_size, phys_addr;
unsigned int irq;
int error;
dev_info(dev, "Device Tree Probing \'%pOFn\'\n", dev->of_node);
/* Get iospace for the device */
error = of_address_to_resource(dev->of_node, 0, &r_mem);
if (error) {
dev_err(dev, "invalid address\n");
return error;
}
/* Get IRQ for the device */
irq = irq_of_parse_and_map(dev->of_node, 0);
if (!irq) {
dev_err(dev, "no IRQ found\n");
return -ENODEV;
}
drvdata = kzalloc(sizeof(*drvdata), GFP_KERNEL);
serio = kzalloc(sizeof(*serio), GFP_KERNEL);
if (!drvdata || !serio) {
error = -ENOMEM;
goto failed1;
}
spin_lock_init(&drvdata->lock);
drvdata->irq = irq;
drvdata->serio = serio;
drvdata->dev = dev;
phys_addr = r_mem.start;
remap_size = resource_size(&r_mem);
if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
(unsigned long long)phys_addr);
error = -EBUSY;
goto failed1;
}
/* Fill in configuration data and add them to the list */
drvdata->base_address = ioremap(phys_addr, remap_size);
if (drvdata->base_address == NULL) {
dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
(unsigned long long)phys_addr);
error = -EFAULT;
goto failed2;
}
/* Disable all the interrupts, just in case */
out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);
/*
* Reset the PS2 device and abort any current transaction,
* to make sure we have the PS2 in a good state.
*/
out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);
dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
(unsigned long long)phys_addr, drvdata->base_address,
drvdata->irq);
serio->id.type = SERIO_8042;
serio->write = sxps2_write;
serio->open = sxps2_open;
serio->close = sxps2_close;
serio->port_data = drvdata;
serio->dev.parent = dev;
snprintf(serio->name, sizeof(serio->name),
"Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
snprintf(serio->phys, sizeof(serio->phys),
"xilinxps2/serio at %08llX", (unsigned long long)phys_addr);
serio_register_port(serio);
platform_set_drvdata(ofdev, drvdata);
return 0; /* success */
failed2:
release_mem_region(phys_addr, remap_size);
failed1:
kfree(serio);
kfree(drvdata);
return error;
}
/**
* xps2_of_remove - unbinds the driver from the PS/2 device.
* @of_dev: pointer to OF device structure
*
* This function is called if a device is physically removed from the system or
* if the driver module is being unloaded. It frees any resources allocated to
* the device.
*/
static void xps2_of_remove(struct platform_device *of_dev)
{
struct xps2data *drvdata = platform_get_drvdata(of_dev);
struct resource r_mem; /* IO mem resources */
serio_unregister_port(drvdata->serio);
iounmap(drvdata->base_address);
/* Get iospace of the device */
if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem))
dev_err(drvdata->dev, "invalid address\n");
else
release_mem_region(r_mem.start, resource_size(&r_mem));
kfree(drvdata);
}
/* Match table for of_platform binding */
static const struct of_device_id xps2_of_match[] = {
{ .compatible = "xlnx,xps-ps2-1.00.a", },
{ /* end of list */ },
};
MODULE_DEVICE_TABLE(of, xps2_of_match);
static struct platform_driver xps2_of_driver = {
.driver = {
.name = DRIVER_NAME,
.of_match_table = xps2_of_match,
},
.probe = xps2_of_probe,
.remove_new = xps2_of_remove,
};
module_platform_driver(xps2_of_driver);
MODULE_AUTHOR("Xilinx, Inc.");
MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
MODULE_LICENSE("GPL");
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