Subject: Re: [PATCH] [V3] powerpc: Xilinx: PS2: Added new XPS PS2 driver

From: Grant Likely <[email-masked]>
Date: Wed, 9 Jul 2008 10:04:07 -0600

On Mon, Jul 07, 2008 at 08:38:45AM -0700, John Linn wrote:
> Added a new driver for Xilinx XPS PS2 IP. This driver is
> a flat driver to better match the Linux driver pattern.
> 
> Signed-off-by: Sadanand <[email-masked]>
> Signed-off-by: John Linn <[email-masked]>

I know there are a couple of minor comments floating around; but as far
as I'm concerned....

Acked-by: Grant Likely <[email-masked]>

> ---
> V2
> 	Updated the driver based on feedback from Dmitry, Peter, and Grant.
> 	We believe Montavista copyright is still valid.
> V3
> 	Incorporated Dmitry and Grant's 2nd set of comments which were some
> 	minor cleanup and removal of the mutex which was not needed.
>  
>  drivers/input/serio/Kconfig      |    5 +
>  drivers/input/serio/Makefile     |    1 +
>  drivers/input/serio/xilinx_ps2.c |  384 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 390 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/input/serio/xilinx_ps2.c
> 
> diff --git a/drivers/input/serio/Kconfig b/drivers/input/serio/Kconfig
> index ec4b661..0e62b39 100644
> --- a/drivers/input/serio/Kconfig
> +++ b/drivers/input/serio/Kconfig
> @@ -190,4 +190,9 @@ config SERIO_RAW
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called serio_raw.
>  
> +config SERIO_XILINX_XPS_PS2
> +	tristate "Xilinx XPS PS/2 Controller Support"
> +	help
> +	  This driver supports XPS PS/2 IP from Xilinx EDK.
> +
>  endif
> diff --git a/drivers/input/serio/Makefile b/drivers/input/serio/Makefile
> index 38b8868..9b6c813 100644
> --- a/drivers/input/serio/Makefile
> +++ b/drivers/input/serio/Makefile
> @@ -21,3 +21,4 @@ obj-$(CONFIG_SERIO_PCIPS2)	+= pcips2.o
>  obj-$(CONFIG_SERIO_MACEPS2)	+= maceps2.o
>  obj-$(CONFIG_SERIO_LIBPS2)	+= libps2.o
>  obj-$(CONFIG_SERIO_RAW)		+= serio_raw.o
> +obj-$(CONFIG_SERIO_XILINX_XPS_PS2)	+= xilinx_ps2.o
> diff --git a/drivers/input/serio/xilinx_ps2.c b/drivers/input/serio/xilinx_ps2.c
> new file mode 100644
> index 0000000..e86f11b
> --- /dev/null
> +++ b/drivers/input/serio/xilinx_ps2.c
> @@ -0,0 +1,384 @@
> +/*
> + * Xilinx XPS PS/2 device driver
> + *
> + * (c) 2005 MontaVista Software, Inc.
> + * (c) 2008 Xilinx, Inc.
> + *
> + * 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.
> + *
> + * You should have received a copy of the GNU General Public License along
> + * with this program; if not, write to the Free Software Foundation, Inc.,
> + * 675 Mass Ave, Cambridge, MA 02139, USA.
> + */
> +
> +
> +#include <linux/module.h>
> +#include <linux/serio.h>
> +#include <linux/interrupt.h>
> +#include <linux/errno.h>
> +#include <linux/init.h>
> +#include <linux/list.h>
> +#include <linux/io.h>
> +
> +#include <linux/of_device.h>
> +#include <linux/of_platform.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;
> +	u32 phys_addr;
> +	u32 remap_size;
> +	spinlock_t lock;
> +	u8 rxb;				/* Rx buffer */
> +	void __iomem *base_address;	/* virt. address of control registers */
> +	unsigned int dfl;
> +	struct serio serio;		/* serio */
> +};
> +
> +/************************************/
> +/* XPS PS/2 data transmission calls */
> +/************************************/
> +
> +/*
> + * xps2_recv() will attempt to receive a byte of data from the PS/2 port.
> + */
> +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 = (struct xps2data *)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) {
> +		printk(KERN_ERR "%s: receive overrun error\n",
> +			drvdata->serio.name);
> +	}
> +
> +	if (intr_sr & XPS2_IPIXR_RX_ERR)
> +		drvdata->dfl |= SERIO_PARITY;
> +
> +	if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
> +		drvdata->dfl |= SERIO_TIMEOUT;
> +
> +	if (intr_sr & XPS2_IPIXR_RX_FULL) {
> +		status = xps2_recv(drvdata, &drvdata->rxb);
> +
> +		/* Error, if a byte is not received */
> +		if (status) {
> +			printk(KERN_ERR
> +				"%s: wrong rcvd byte count (%d)\n",
> +				drvdata->serio.name, status);
> +		} else {
> +			c = drvdata->rxb;
> +			serio_interrupt(&drvdata->serio, c, drvdata->dfl);
> +			drvdata->dfl = 0;
> +		}
> +	}
> +
> +	if (intr_sr & XPS2_IPIXR_TX_ACK)
> +		drvdata->dfl = 0;
> +
> +	return IRQ_HANDLED;
> +}
> +
> +/*******************/
> +/* serio callbacks */
> +/*******************/
> +
> +/*
> + * sxps2_write() sends a byte out through the PS/2 interface.
> + */
> +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) == 0) {
> +		out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
> +		status = 0;
> +	}
> +	spin_unlock_irqrestore(&drvdata->lock, flags);
> +
> +	return status;
> +}
> +
> +/*
> + * sxps2_open() is called when a port is open by the higher layer.
> + */
> +static int sxps2_open(struct serio *pserio)
> +{
> +	struct xps2data *drvdata = pserio->port_data;
> +	int retval;
> +
> +	retval = request_irq(drvdata->irq, &xps2_interrupt, 0,
> +				DRIVER_NAME, drvdata);
> +	if (retval) {
> +		printk(KERN_ERR
> +			"%s: Couldn't allocate interrupt %d\n",
> +			drvdata->serio.name, drvdata->irq);
> +		return retval;
> +	}
> +
> +	/* 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, &drvdata->rxb);
> +
> +	return 0;		/* success */
> +}
> +
> +/*
> + * sxps2_close() frees the interrupt.
> + */
> +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);
> +}
> +
> +/*********************/
> +/* Device setup code */
> +/*********************/
> +
> +static int xps2_setup(struct device *dev, struct resource *regs_res,
> +		      struct resource *irq_res)
> +{
> +	struct xps2data *drvdata;
> +	struct serio *serio;
> +	unsigned long remap_size;
> +	int retval;
> +
> +	if (!dev)
> +		return -EINVAL;
> +
> +	drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
> +	if (!drvdata) {
> +		dev_err(dev, "Couldn't allocate device private record\n");
> +		return -ENOMEM;
> +	}
> +	spin_lock_init(&drvdata->lock);
> +	dev_set_drvdata(dev, drvdata);
> +
> +	if (!regs_res || !irq_res) {
> +		dev_err(dev, "IO resource(s) not found\n");
> +		retval = -EFAULT;
> +		goto failed1;
> +	}
> +
> +	drvdata->irq = irq_res->start;
> +	remap_size = regs_res->end - regs_res->start + 1;
> +	if (!request_mem_region(regs_res->start, remap_size, DRIVER_NAME)) {
> +
> +		dev_err(dev, "Couldn't lock memory region at 0x%08X\n",
> +			(unsigned int)regs_res->start);
> +		retval = -EBUSY;
> +		goto failed1;
> +	}
> +
> +	/* Fill in configuration data and add them to the list */
> +	drvdata->phys_addr = regs_res->start;
> +	drvdata->remap_size = remap_size;
> +	drvdata->base_address = ioremap(regs_res->start, remap_size);
> +	if (drvdata->base_address == NULL) {
> +
> +		dev_err(dev, "Couldn't ioremap memory at 0x%08X\n",
> +			(unsigned int)regs_res->start);
> +		retval = -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%08X mapped to 0x%08X, irq=%d\n",
> +		drvdata->phys_addr, (u32)drvdata->base_address, drvdata->irq);
> +
> +	serio = &drvdata->serio;
> +	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(drvdata->serio.name, sizeof(serio->name),
> +		 "Xilinx XPS PS/2 at %08X", drvdata->phys_addr);
> +	snprintf(drvdata->serio.phys, sizeof(serio->phys),
> +		 "xilinxps2/serio at %08X", drvdata->phys_addr);
> +	serio_register_port(serio);
> +
> +	return 0;		/* success */
> +
> +failed2:
> +	release_mem_region(regs_res->start, remap_size);
> +
> +failed1:
> +	kfree(drvdata);
> +	dev_set_drvdata(dev, NULL);
> +
> +	return retval;
> +}
> +
> +/***************************/
> +/* OF Platform Bus Support */
> +/***************************/
> +
> +static int __devinit xps2_of_probe(struct of_device *ofdev, const struct
> +				   of_device_id * match)
> +{
> +	struct resource r_irq; /* Interrupt resources */
> +	struct resource r_mem; /* IO mem resources */
> +	int rc = 0;
> +
> +	printk(KERN_INFO "Device Tree Probing \'%s\'\n",
> +			ofdev->node->name);
> +
> +	/* Get iospace for the device */
> +	rc = of_address_to_resource(ofdev->node, 0, &r_mem);
> +	if (rc) {
> +		dev_err(&ofdev->dev, "invalid address\n");
> +		return rc;
> +	}
> +
> +	/* Get IRQ for the device */
> +	rc = of_irq_to_resource(ofdev->node, 0, &r_irq);
> +	if (rc == NO_IRQ) {
> +		dev_err(&ofdev->dev, "no IRQ found\n");
> +		return rc;
> +	}
> +
> +	return xps2_setup(&ofdev->dev, &r_mem, &r_irq);
> +}
> +
> +static int __devexit xps2_of_remove(struct of_device *of_dev)
> +{
> +	struct xps2data *drvdata;
> +	struct device *dev;
> +
> +	dev = &of_dev->dev;
> +	if (!dev)
> +		return -EINVAL;
> +
> +	drvdata = (struct xps2data *)dev_get_drvdata(dev);
> +
> +	serio_unregister_port(&drvdata->serio);
> +
> +	iounmap(drvdata->base_address);
> +
> +	release_mem_region(drvdata->phys_addr, drvdata->remap_size);
> +
> +	kfree(drvdata);
> +	dev_set_drvdata(dev, NULL);
> +
> +	return 0;		/* success */
> +}
> +
> +/* Match table for of_platform binding */
> +static struct of_device_id xps2_of_match[] __devinitdata = {
> +	{ .compatible = "xlnx,xps-ps2-1.00.a", },
> +	{ /* end of list */ },
> +};
> +MODULE_DEVICE_TABLE(of, xps2_of_match);
> +
> +static struct of_platform_driver xps2_of_driver = {
> +	.name		= DRIVER_NAME,
> +	.match_table	= xps2_of_match,
> +	.probe		= xps2_of_probe,
> +	.remove		= __devexit_p(xps2_of_remove),
> +};
> +
> +static int __init xps2_init(void)
> +{
> +	return of_register_platform_driver(&xps2_of_driver);
> +}
> +
> +static void __exit xps2_cleanup(void)
> +{
> +	of_unregister_platform_driver(&xps2_of_driver);
> +}
> +
> +module_init(xps2_init);
> +module_exit(xps2_cleanup);
> +
> +MODULE_AUTHOR("Xilinx, Inc.");
> +MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
> +MODULE_LICENSE("GPL");
> +
> -- 
> 1.5.2.1
> 
> 
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