net/can: add driver for mscan family & mpc52xx_mscan

Taken from socketcan-svn, fixed remaining todos, cleaned up, tested with a
phyCORE-MPC5200B-IO and a custom board.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/powerpc/dts-bindings/fsl/mpc5200.txt

@@ -178,3 +178,12 @@ External interrupts:
 	external irq3:	interrupts = <1 3 n>;
 'n' is sense (0: level high, 1: edge rising, 2: edge falling 3: level low)
 
+fsl,mpc5200-mscan nodes
+-----------------------
+In addition to the required compatible-, reg- and interrupt-properites, you can
+also specify which clock shall be used for the bus:
+
+- fsl,mscan-clk-src	- a string describing the clock source. Valid values
+			  are "ip" for IP_CLK and "sys" for SYS_XTAL.
+			  "sys" is the default in case the property is not
+			  present.

drivers/net/can/Kconfig

@@ -108,6 +108,25 @@ config CAN_MCP251X
 	---help---
 	  Driver for the Microchip MCP251x SPI CAN controllers.
 
+config CAN_MSCAN
+	depends on CAN_DEV && (PPC || M68K || M68KNOMMU)
+	tristate "Support for Freescale MSCAN based chips"
+	---help---
+	  The Motorola Scalable Controller Area Network (MSCAN) definition
+	  is based on the MSCAN12 definition which is the specific
+	  implementation of the Motorola Scalable CAN concept targeted for
+	  the Motorola MC68HC12 Microcontroller Family.
+
+config CAN_MPC52XX
+	tristate "Freescale MPC5xxx onboard CAN controller"
+	depends on CAN_MSCAN && PPC_MPC52xx
+	---help---
+	  If you say yes here you get support for Freescale's MPC52xx
+	  onboard dualCAN controller.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called mpc5xxx_can.
+
 config CAN_DEBUG_DEVICES
 	bool "CAN devices debugging messages"
 	depends on CAN

drivers/net/can/Makefile

@@ -10,6 +10,7 @@ can-dev-y			:= dev.o
 obj-y				+= usb/
 
 obj-$(CONFIG_CAN_SJA1000)	+= sja1000/
+obj-$(CONFIG_CAN_MSCAN)		+= mscan/
 obj-$(CONFIG_CAN_AT91)		+= at91_can.o
 obj-$(CONFIG_CAN_TI_HECC)	+= ti_hecc.o
 obj-$(CONFIG_CAN_MCP251X)	+= mcp251x.o

drivers/net/can/mscan/Makefile

@@ -0,0 +1,5 @@
+
+obj-$(CONFIG_CAN_MPC52XX)	+= mscan-mpc52xx.o
+mscan-mpc52xx-objs		:= mscan.o mpc52xx_can.o
+
+ccflags-$(CONFIG_CAN_DEBUG_DEVICES) := -DDEBUG

drivers/net/can/mscan/mpc52xx_can.c

@@ -0,0 +1,279 @@
+/*
+ * CAN bus driver for the Freescale MPC5xxx embedded CPU.
+ *
+ * Copyright (C) 2004-2005 Andrey Volkov <avolkov@varma-el.com>,
+ *                         Varma Electronics Oy
+ * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
+ * Copyright (C) 2009 Wolfram Sang, Pengutronix <w.sang@pengutronix.de>
+ *
+ * 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.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/netdevice.h>
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <linux/of_platform.h>
+#include <sysdev/fsl_soc.h>
+#include <linux/io.h>
+#include <asm/mpc52xx.h>
+
+#include "mscan.h"
+
+
+#define DRV_NAME "mpc5xxx_can"
+
+static struct of_device_id mpc52xx_cdm_ids[] __devinitdata = {
+	{ .compatible = "fsl,mpc5200-cdm", },
+	{ .compatible = "fsl,mpc5200b-cdm", },
+	{}
+};
+
+/*
+ * Get the frequency of the external oscillator clock connected
+ * to the SYS_XTAL_IN pin, or return 0 if it cannot be determined.
+ */
+static unsigned int  __devinit mpc52xx_can_xtal_freq(struct of_device *of)
+{
+	struct mpc52xx_cdm  __iomem *cdm;
+	struct device_node *np_cdm;
+	unsigned int freq;
+	u32 val;
+
+	freq = mpc5xxx_get_bus_frequency(of->node);
+	if (!freq)
+		return 0;
+
+	/*
+	 * Determine SYS_XTAL_IN frequency from the clock domain settings
+	 */
+	np_cdm = of_find_matching_node(NULL, mpc52xx_cdm_ids);
+	if (!np_cdm) {
+		dev_err(&of->dev, "can't get clock node!\n");
+		return 0;
+	}
+	cdm = of_iomap(np_cdm, 0);
+	of_node_put(np_cdm);
+
+	if (in_8(&cdm->ipb_clk_sel) & 0x1)
+		freq *= 2;
+	val  = in_be32(&cdm->rstcfg);
+	if (val & (1 << 5))
+		freq *= 8;
+	else
+		freq *= 4;
+	if (val & (1 << 6))
+		freq /= 12;
+	else
+		freq /= 16;
+
+	iounmap(cdm);
+
+	return freq;
+}
+
+/*
+ * Get frequency of the MSCAN clock source
+ *
+ * Either the oscillator clock (SYS_XTAL_IN) or the IP bus clock (IP_CLK)
+ * can be selected. According to the MPC5200 user's manual, the oscillator
+ * clock is the better choice as it has less jitter but due to a hardware
+ * bug, it can not be selected for the old MPC5200 Rev. A chips.
+ */
+
+static unsigned int  __devinit mpc52xx_can_clock_freq(struct of_device *of,
+						      int clock_src)
+{
+	unsigned int pvr;
+
+	pvr = mfspr(SPRN_PVR);
+
+	if (clock_src == MSCAN_CLKSRC_BUS || pvr == 0x80822011)
+		return mpc5xxx_get_bus_frequency(of->node);
+
+	return mpc52xx_can_xtal_freq(of);
+}
+
+static int __devinit mpc5xxx_can_probe(struct of_device *ofdev,
+				       const struct of_device_id *id)
+{
+	struct device_node *np = ofdev->node;
+	struct net_device *dev;
+	struct mscan_priv *priv;
+	void __iomem *base;
+	const char *clk_src;
+	int err, irq, clock_src;
+
+	base = of_iomap(ofdev->node, 0);
+	if (!base) {
+		dev_err(&ofdev->dev, "couldn't ioremap\n");
+		err = -ENOMEM;
+		goto exit_release_mem;
+	}
+
+	irq = irq_of_parse_and_map(np, 0);
+	if (!irq) {
+		dev_err(&ofdev->dev, "no irq found\n");
+		err = -ENODEV;
+		goto exit_unmap_mem;
+	}
+
+	dev = alloc_mscandev();
+	if (!dev) {
+		err = -ENOMEM;
+		goto exit_dispose_irq;
+	}
+
+	priv = netdev_priv(dev);
+	priv->reg_base = base;
+	dev->irq = irq;
+
+	/*
+	 * Either the oscillator clock (SYS_XTAL_IN) or the IP bus clock
+	 * (IP_CLK) can be selected as MSCAN clock source. According to
+	 * the MPC5200 user's manual, the oscillator clock is the better
+	 * choice as it has less jitter. For this reason, it is selected
+	 * by default.
+	 */
+	clk_src = of_get_property(np, "fsl,mscan-clk-src", NULL);
+	if (clk_src && strcmp(clk_src, "ip") == 0)
+		clock_src = MSCAN_CLKSRC_BUS;
+	else
+		clock_src = MSCAN_CLKSRC_XTAL;
+	priv->can.clock.freq = mpc52xx_can_clock_freq(ofdev, clock_src);
+	if (!priv->can.clock.freq) {
+		dev_err(&ofdev->dev, "couldn't get MSCAN clock frequency\n");
+		err = -ENODEV;
+		goto exit_free_mscan;
+	}
+
+	SET_NETDEV_DEV(dev, &ofdev->dev);
+
+	err = register_mscandev(dev, clock_src);
+	if (err) {
+		dev_err(&ofdev->dev, "registering %s failed (err=%d)\n",
+			DRV_NAME, err);
+		goto exit_free_mscan;
+	}
+
+	dev_set_drvdata(&ofdev->dev, dev);
+
+	dev_info(&ofdev->dev, "MSCAN at 0x%p, irq %d, clock %d Hz\n",
+		 priv->reg_base, dev->irq, priv->can.clock.freq);
+
+	return 0;
+
+exit_free_mscan:
+	free_candev(dev);
+exit_dispose_irq:
+	irq_dispose_mapping(irq);
+exit_unmap_mem:
+	iounmap(base);
+exit_release_mem:
+	return err;
+}
+
+static int __devexit mpc5xxx_can_remove(struct of_device *ofdev)
+{
+	struct net_device *dev = dev_get_drvdata(&ofdev->dev);
+	struct mscan_priv *priv = netdev_priv(dev);
+
+	dev_set_drvdata(&ofdev->dev, NULL);
+
+	unregister_mscandev(dev);
+	iounmap(priv->reg_base);
+	irq_dispose_mapping(dev->irq);
+	free_candev(dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static struct mscan_regs saved_regs;
+static int mpc5xxx_can_suspend(struct of_device *ofdev, pm_message_t state)
+{
+	struct net_device *dev = dev_get_drvdata(&ofdev->dev);
+	struct mscan_priv *priv = netdev_priv(dev);
+	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
+
+	_memcpy_fromio(&saved_regs, regs, sizeof(*regs));
+
+	return 0;
+}
+
+static int mpc5xxx_can_resume(struct of_device *ofdev)
+{
+	struct net_device *dev = dev_get_drvdata(&ofdev->dev);
+	struct mscan_priv *priv = netdev_priv(dev);
+	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
+
+	regs->canctl0 |= MSCAN_INITRQ;
+	while ((regs->canctl1 & MSCAN_INITAK) == 0)
+		udelay(10);
+
+	regs->canctl1 = saved_regs.canctl1;
+	regs->canbtr0 = saved_regs.canbtr0;
+	regs->canbtr1 = saved_regs.canbtr1;
+	regs->canidac = saved_regs.canidac;
+
+	/* restore masks, buffers etc. */
+	_memcpy_toio(&regs->canidar1_0, (void *)&saved_regs.canidar1_0,
+		     sizeof(*regs) - offsetof(struct mscan_regs, canidar1_0));
+
+	regs->canctl0 &= ~MSCAN_INITRQ;
+	regs->cantbsel = saved_regs.cantbsel;
+	regs->canrier = saved_regs.canrier;
+	regs->cantier = saved_regs.cantier;
+	regs->canctl0 = saved_regs.canctl0;
+
+	return 0;
+}
+#endif
+
+static struct of_device_id __devinitdata mpc5xxx_can_table[] = {
+	{.compatible = "fsl,mpc5200-mscan"},
+	{.compatible = "fsl,mpc5200b-mscan"},
+	{},
+};
+
+static struct of_platform_driver mpc5xxx_can_driver = {
+	.owner = THIS_MODULE,
+	.name = "mpc5xxx_can",
+	.probe = mpc5xxx_can_probe,
+	.remove = __devexit_p(mpc5xxx_can_remove),
+#ifdef CONFIG_PM
+	.suspend = mpc5xxx_can_suspend,
+	.resume = mpc5xxx_can_resume,
+#endif
+	.match_table = mpc5xxx_can_table,
+};
+
+static int __init mpc5xxx_can_init(void)
+{
+	return of_register_platform_driver(&mpc5xxx_can_driver);
+}
+module_init(mpc5xxx_can_init);
+
+static void __exit mpc5xxx_can_exit(void)
+{
+	return of_unregister_platform_driver(&mpc5xxx_can_driver);
+};
+module_exit(mpc5xxx_can_exit);
+
+MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
+MODULE_DESCRIPTION("Freescale MPC5200 CAN driver");
+MODULE_LICENSE("GPL v2");