can/sja1000: add driver for EMS PCMCIA card

This patch adds the driver for the SJA1000 based PCMCIA card 'CPC-Card' from
EMS Dr. Thomas Wuensche (http://www.ems-wuensche.de).

Signed-off-by: Oliver Hartkopp <[e-mail]>
Acked-by: Markus Plessing <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/can/sja1000/Kconfig

···
 	  OpenFirmware bindings, e.g. if you have a PowerPC based system
 	  you may want to enable this option.
 
+config CAN_EMS_PCMCIA
+	tristate "EMS CPC-CARD Card"
+	depends on PCMCIA
+	---help---
+	  This driver is for the one or two channel CPC-CARD cards from
+	  EMS Dr. Thomas Wuensche (http://www.ems-wuensche.de).
+
 config CAN_EMS_PCI
 	tristate "EMS CPC-PCI, CPC-PCIe and CPC-104P Card"
 	depends on PCI

drivers/net/can/sja1000/Makefile

···
 obj-$(CONFIG_CAN_SJA1000_ISA) += sja1000_isa.o
 obj-$(CONFIG_CAN_SJA1000_PLATFORM) += sja1000_platform.o
 obj-$(CONFIG_CAN_SJA1000_OF_PLATFORM) += sja1000_of_platform.o
+obj-$(CONFIG_CAN_EMS_PCMCIA) += ems_pcmcia.o
 obj-$(CONFIG_CAN_EMS_PCI) += ems_pci.o
 obj-$(CONFIG_CAN_KVASER_PCI) += kvaser_pci.o
 obj-$(CONFIG_CAN_PEAK_PCI) += peak_pci.o

drivers/net/can/sja1000/ems_pcmcia.c

···
+/*
+ * Copyright (C) 2008 Sebastian Haas (initial chardev implementation)
+ * Copyright (C) 2010 Markus Plessing <[e-mail]>
+ * Rework for mainline by Oliver Hartkopp <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the version 2 of the GNU General Public License
+ * as published by the Free Software Foundation
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/netdevice.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <pcmcia/cistpl.h>
+#include <pcmcia/ds.h>
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include "sja1000.h"
+
+#define DRV_NAME "ems_pcmcia"
+
+MODULE_AUTHOR("Markus Plessing <[e-mail]>");
+MODULE_DESCRIPTION("Socket-CAN driver for EMS CPC-CARD cards");
+MODULE_SUPPORTED_DEVICE("EMS CPC-CARD CAN card");
+MODULE_LICENSE("GPL v2");
+
+#define EMS_PCMCIA_MAX_CHAN 2
+
+struct ems_pcmcia_card {
+	int channels;
+	struct pcmcia_device *pcmcia_dev;
+	struct net_device *net_dev[EMS_PCMCIA_MAX_CHAN];
+	void __iomem *base_addr;
+};
+
+#define EMS_PCMCIA_CAN_CLOCK (16000000 / 2)
+
+/*
+ * The board configuration is probably following:
+ * RX1 is connected to ground.
+ * TX1 is not connected.
+ * CLKO is not connected.
+ * Setting the OCR register to 0xDA is a good idea.
+ * This means  normal output mode , push-pull and the correct polarity.
+ */
+#define EMS_PCMCIA_OCR (OCR_TX0_PUSHPULL | OCR_TX1_PUSHPULL)
+
+/*
+ * In the CDR register, you should set CBP to 1.
+ * You will probably also want to set the clock divider value to 7
+ * (meaning direct oscillator output) because the second SJA1000 chip
+ * is driven by the first one CLKOUT output.
+ */
+#define EMS_PCMCIA_CDR (CDR_CBP | CDR_CLKOUT_MASK)
+#define EMS_PCMCIA_MEM_SIZE 4096 /* Size of the remapped io-memory */
+#define EMS_PCMCIA_CAN_BASE_OFFSET 0x100 /* Offset where controllers starts */
+#define EMS_PCMCIA_CAN_CTRL_SIZE 0x80 /* Memory size for each controller */
+
+#define EMS_CMD_RESET 0x00 /* Perform a reset of the card */
+#define EMS_CMD_MAP   0x03 /* Map CAN controllers into card' memory */
+#define EMS_CMD_UMAP  0x02 /* Unmap CAN controllers from card' memory */
+
+static struct pcmcia_device_id ems_pcmcia_tbl[] = {
+	PCMCIA_DEVICE_PROD_ID123("EMS_T_W", "CPC-Card", "V2.0", 0xeab1ea23,
+				 0xa338573f, 0xe4575800),
+	PCMCIA_DEVICE_NULL,
+};
+
+MODULE_DEVICE_TABLE(pcmcia, ems_pcmcia_tbl);
+
+static u8 ems_pcmcia_read_reg(const struct sja1000_priv *priv, int port)
+{
+	return readb(priv->reg_base + port);
+}
+
+static void ems_pcmcia_write_reg(const struct sja1000_priv *priv, int port,
+				 u8 val)
+{
+	writeb(val, priv->reg_base + port);
+}
+
+static irqreturn_t ems_pcmcia_interrupt(int irq, void *dev_id)
+{
+	struct ems_pcmcia_card *card = dev_id;
+	struct net_device *dev;
+	irqreturn_t retval = IRQ_NONE;
+	int i, again;
+
+	/* Card not present */
+	if (readw(card->base_addr) != 0xAA55)
+		return IRQ_HANDLED;
+
+	do {
+		again = 0;
+
+		/* Check interrupt for each channel */
+		for (i = 0; i < card->channels; i++) {
+			dev = card->net_dev[i];
+			if (!dev)
+				continue;
+
+			if (sja1000_interrupt(irq, dev) == IRQ_HANDLED)
+				again = 1;
+		}
+		/* At least one channel handled the interrupt */
+		if (again)
+			retval = IRQ_HANDLED;
+
+	} while (again);
+
+	return retval;
+}
+
+/*
+ * Check if a CAN controller is present at the specified location
+ * by trying to set 'em into the PeliCAN mode
+ */
+static inline int ems_pcmcia_check_chan(struct sja1000_priv *priv)
+{
+	/* Make sure SJA1000 is in reset mode */
+	ems_pcmcia_write_reg(priv, REG_MOD, 1);
+	ems_pcmcia_write_reg(priv, REG_CDR, CDR_PELICAN);
+
+	/* read reset-values */
+	if (ems_pcmcia_read_reg(priv, REG_CDR) == CDR_PELICAN)
+		return 1;
+
+	return 0;
+}
+
+static void ems_pcmcia_del_card(struct pcmcia_device *pdev)
+{
+	struct ems_pcmcia_card *card = pdev->priv;
+	struct net_device *dev;
+	int i;
+
+	free_irq(pdev->irq, card);
+
+	for (i = 0; i < card->channels; i++) {
+		dev = card->net_dev[i];
+		if (!dev)
+			continue;
+
+		printk(KERN_INFO "%s: removing %s on channel #%d\n",
+		       DRV_NAME, dev->name, i);
+		unregister_sja1000dev(dev);
+		free_sja1000dev(dev);
+	}
+
+	writeb(EMS_CMD_UMAP, card->base_addr);
+	iounmap(card->base_addr);
+	kfree(card);
+
+	pdev->priv = NULL;
+}
+
+/*
+ * Probe PCI device for EMS CAN signature and register each available
+ * CAN channel to SJA1000 Socket-CAN subsystem.
+ */
+static int __devinit ems_pcmcia_add_card(struct pcmcia_device *pdev,
+					 unsigned long base)
+{
+	struct sja1000_priv *priv;
+	struct net_device *dev;
+	struct ems_pcmcia_card *card;
+	int err, i;
+
+	/* Allocating card structures to hold addresses, ... */
+	card = kzalloc(sizeof(struct ems_pcmcia_card), GFP_KERNEL);
+	if (!card)
+		return -ENOMEM;
+
+	pdev->priv = card;
+	card->channels = 0;
+
+	card->base_addr = ioremap(base, EMS_PCMCIA_MEM_SIZE);
+	if (!card->base_addr) {
+		err = -ENOMEM;
+		goto failure_cleanup;
+	}
+
+	/* Check for unique EMS CAN signature */
+	if (readw(card->base_addr) != 0xAA55) {
+		err = -ENODEV;
+		goto failure_cleanup;
+	}
+
+	/* Request board reset */
+	writeb(EMS_CMD_RESET, card->base_addr);
+
+	/* Make sure CAN controllers are mapped into card's memory space */
+	writeb(EMS_CMD_MAP, card->base_addr);
+
+	/* Detect available channels */
+	for (i = 0; i < EMS_PCMCIA_MAX_CHAN; i++) {
+		dev = alloc_sja1000dev(0);
+		if (!dev) {
+			err = -ENOMEM;
+			goto failure_cleanup;
+		}
+
+		card->net_dev[i] = dev;
+		priv = netdev_priv(dev);
+		priv->priv = card;
+		SET_NETDEV_DEV(dev, &pdev->dev);
+
+		priv->irq_flags = IRQF_SHARED;
+		dev->irq = pdev->irq;
+		priv->reg_base = card->base_addr + EMS_PCMCIA_CAN_BASE_OFFSET +
+			(i * EMS_PCMCIA_CAN_CTRL_SIZE);
+
+		/* Check if channel is present */
+		if (ems_pcmcia_check_chan(priv)) {
+			priv->read_reg  = ems_pcmcia_read_reg;
+			priv->write_reg = ems_pcmcia_write_reg;
+			priv->can.clock.freq = EMS_PCMCIA_CAN_CLOCK;
+			priv->ocr = EMS_PCMCIA_OCR;
+			priv->cdr = EMS_PCMCIA_CDR;
+			priv->flags |= SJA1000_CUSTOM_IRQ_HANDLER;
+
+			/* Register SJA1000 device */
+			err = register_sja1000dev(dev);
+			if (err) {
+				free_sja1000dev(dev);
+				goto failure_cleanup;
+			}
+
+			card->channels++;
+
+			printk(KERN_INFO "%s: registered %s on channel "
+			       "#%d at 0x%p, irq %d\n", DRV_NAME, dev->name,
+			       i, priv->reg_base, dev->irq);
+		} else
+			free_sja1000dev(dev);
+	}
+
+	err = request_irq(dev->irq, &ems_pcmcia_interrupt, IRQF_SHARED,
+			  DRV_NAME, card);
+	if (!err)
+		return 0;
+
+failure_cleanup:
+	ems_pcmcia_del_card(pdev);
+	return err;
+}
+
+/*
+ * Setup PCMCIA socket and probe for EMS CPC-CARD
+ */
+static int __devinit ems_pcmcia_probe(struct pcmcia_device *dev)
+{
+	int csval;
+
+	/* General socket configuration */
+	dev->config_flags |= CONF_ENABLE_IRQ;
+	dev->config_index = 1;
+	dev->config_regs = PRESENT_OPTION;
+
+	/* The io structure describes IO port mapping */
+	dev->resource[0]->end = 16;
+	dev->resource[0]->flags |= IO_DATA_PATH_WIDTH_8;
+	dev->resource[1]->end = 16;
+	dev->resource[1]->flags |= IO_DATA_PATH_WIDTH_16;
+	dev->io_lines = 5;
+
+	/* Allocate a memory window */
+	dev->resource[2]->flags =
+		(WIN_DATA_WIDTH_8 | WIN_MEMORY_TYPE_CM | WIN_ENABLE);
+	dev->resource[2]->start = dev->resource[2]->end = 0;
+
+	csval = pcmcia_request_window(dev, dev->resource[2], 0);
+	if (csval) {
+		dev_err(&dev->dev, "pcmcia_request_window failed (err=%d)\n",
+			csval);
+		return 0;
+	}
+
+	csval = pcmcia_map_mem_page(dev, dev->resource[2], dev->config_base);
+	if (csval) {
+		dev_err(&dev->dev, "pcmcia_map_mem_page failed (err=%d)\n",
+			csval);
+		return 0;
+	}
+
+	csval = pcmcia_enable_device(dev);
+	if (csval) {
+		dev_err(&dev->dev, "pcmcia_enable_device failed (err=%d)\n",
+			csval);
+		return 0;
+	}
+
+	ems_pcmcia_add_card(dev, dev->resource[2]->start);
+	return 0;
+}
+
+/*
+ * Release claimed resources
+ */
+static void ems_pcmcia_remove(struct pcmcia_device *dev)
+{
+	ems_pcmcia_del_card(dev);
+	pcmcia_disable_device(dev);
+}
+
+static struct pcmcia_driver ems_pcmcia_driver = {
+	.name = DRV_NAME,
+	.probe = ems_pcmcia_probe,
+	.remove = ems_pcmcia_remove,
+	.id_table = ems_pcmcia_tbl,
+};
+
+static int __init ems_pcmcia_init(void)
+{
+	return pcmcia_register_driver(&ems_pcmcia_driver);
+}
+module_init(ems_pcmcia_init);
+
+static void __exit ems_pcmcia_exit(void)
+{
+	pcmcia_unregister_driver(&ems_pcmcia_driver);
+}
+module_exit(ems_pcmcia_exit);