can: c_can: Added support for Bosch C_CAN controller

Bosch C_CAN controller is a full-CAN implementation which is compliant
to CAN protocol version 2.0 part A and B. Bosch C_CAN user manual can be
obtained from:

http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/c_can/users_manual_c_can.pdf

This patch adds the support for this controller.
The following are the design choices made while writing the controller
driver:
1. Interface Register set IF1 has be used only in the current design.
2. Out of the 32 Message objects available, 16 are kept aside for RX
   purposes and the rest for TX purposes.
3. NAPI implementation is such that both the TX and RX paths function
   in polling mode.

Signed-off-by: Bhupesh Sharma <bhupesh.sharma@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 215 insertions, 0 deletions

diff --git a/drivers/net/can/c_can/c_can_platform.c b/drivers/net/can/c_can/c_can_platform.c
new file mode 100644
index 000000000000..e629b961ae2d
--- /dev/null
+++ b/drivers/net/can/c_can/c_can_platform.c
@@ -0,0 +1,215 @@
+/*
+ * Platform CAN bus driver for Bosch C_CAN controller
+ *
+ * Copyright (C) 2010 ST Microelectronics
+ * Bhupesh Sharma <bhupesh.sharma@st.com>
+ *
+ * Borrowed heavily from the C_CAN driver originally written by:
+ * Copyright (C) 2007
+ * - Sascha Hauer, Marc Kleine-Budde, Pengutronix <s.hauer@pengutronix.de>
+ * - Simon Kallweit, intefo AG <simon.kallweit@intefo.ch>
+ *
+ * Bosch C_CAN controller is compliant to CAN protocol version 2.0 part A and B.
+ * Bosch C_CAN user manual can be obtained from:
+ * http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/c_can/
+ * users_manual_c_can.pdf
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/kernel.h>
+#include <linux/version.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/list.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+
+#include <linux/can/dev.h>
+
+#include "c_can.h"
+
+/*
+ * 16-bit c_can registers can be arranged differently in the memory
+ * architecture of different implementations. For example: 16-bit
+ * registers can be aligned to a 16-bit boundary or 32-bit boundary etc.
+ * Handle the same by providing a common read/write interface.
+ */
+static u16 c_can_plat_read_reg_aligned_to_16bit(struct c_can_priv *priv,
+						void *reg)
+{
+	return readw(reg);
+}
+
+static void c_can_plat_write_reg_aligned_to_16bit(struct c_can_priv *priv,
+						void *reg, u16 val)
+{
+	writew(val, reg);
+}
+
+static u16 c_can_plat_read_reg_aligned_to_32bit(struct c_can_priv *priv,
+						void *reg)
+{
+	return readw(reg + (long)reg - (long)priv->regs);
+}
+
+static void c_can_plat_write_reg_aligned_to_32bit(struct c_can_priv *priv,
+						void *reg, u16 val)
+{
+	writew(val, reg + (long)reg - (long)priv->regs);
+}
+
+static int __devinit c_can_plat_probe(struct platform_device *pdev)
+{
+	int ret;
+	void __iomem *addr;
+	struct net_device *dev;
+	struct c_can_priv *priv;
+	struct resource *mem, *irq;
+#ifdef CONFIG_HAVE_CLK
+	struct clk *clk;
+
+	/* get the appropriate clk */
+	clk = clk_get(&pdev->dev, NULL);
+	if (IS_ERR(clk)) {
+		dev_err(&pdev->dev, "no clock defined\n");
+		ret = -ENODEV;
+		goto exit;
+	}
+#endif
+
+	/* get the platform data */
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (!mem || (irq <= 0)) {
+		ret = -ENODEV;
+		goto exit_free_clk;
+	}
+
+	if (!request_mem_region(mem->start, resource_size(mem),
+				KBUILD_MODNAME)) {
+		dev_err(&pdev->dev, "resource unavailable\n");
+		ret = -ENODEV;
+		goto exit_free_clk;
+	}
+
+	addr = ioremap(mem->start, resource_size(mem));
+	if (!addr) {
+		dev_err(&pdev->dev, "failed to map can port\n");
+		ret = -ENOMEM;
+		goto exit_release_mem;
+	}
+
+	/* allocate the c_can device */
+	dev = alloc_c_can_dev();
+	if (!dev) {
+		ret = -ENOMEM;
+		goto exit_iounmap;
+	}
+
+	priv = netdev_priv(dev);
+
+	dev->irq = irq->start;
+	priv->regs = addr;
+#ifdef CONFIG_HAVE_CLK
+	priv->can.clock.freq = clk_get_rate(clk);
+	priv->priv = clk;
+#endif
+
+	switch (mem->flags & IORESOURCE_MEM_TYPE_MASK) {
+	case IORESOURCE_MEM_32BIT:
+		priv->read_reg = c_can_plat_read_reg_aligned_to_32bit;
+		priv->write_reg = c_can_plat_write_reg_aligned_to_32bit;
+		break;
+	case IORESOURCE_MEM_16BIT:
+	default:
+		priv->read_reg = c_can_plat_read_reg_aligned_to_16bit;
+		priv->write_reg = c_can_plat_write_reg_aligned_to_16bit;
+		break;
+	}
+
+	platform_set_drvdata(pdev, dev);
+	SET_NETDEV_DEV(dev, &pdev->dev);
+
+	ret = register_c_can_dev(dev);
+	if (ret) {
+		dev_err(&pdev->dev, "registering %s failed (err=%d)\n",
+			KBUILD_MODNAME, ret);
+		goto exit_free_device;
+	}
+
+	dev_info(&pdev->dev, "%s device registered (regs=%p, irq=%d)\n",
+		 KBUILD_MODNAME, priv->regs, dev->irq);
+	return 0;
+
+exit_free_device:
+	platform_set_drvdata(pdev, NULL);
+	free_c_can_dev(dev);
+exit_iounmap:
+	iounmap(addr);
+exit_release_mem:
+	release_mem_region(mem->start, resource_size(mem));
+exit_free_clk:
+#ifdef CONFIG_HAVE_CLK
+	clk_put(clk);
+exit:
+#endif
+	dev_err(&pdev->dev, "probe failed\n");
+
+	return ret;
+}
+
+static int __devexit c_can_plat_remove(struct platform_device *pdev)
+{
+	struct net_device *dev = platform_get_drvdata(pdev);
+	struct c_can_priv *priv = netdev_priv(dev);
+	struct resource *mem;
+
+	unregister_c_can_dev(dev);
+	platform_set_drvdata(pdev, NULL);
+
+	free_c_can_dev(dev);
+	iounmap(priv->regs);
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	release_mem_region(mem->start, resource_size(mem));
+
+#ifdef CONFIG_HAVE_CLK
+	clk_put(priv->priv);
+#endif
+
+	return 0;
+}
+
+static struct platform_driver c_can_plat_driver = {
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.owner = THIS_MODULE,
+	},
+	.probe = c_can_plat_probe,
+	.remove = __devexit_p(c_can_plat_remove),
+};
+
+static int __init c_can_plat_init(void)
+{
+	return platform_driver_register(&c_can_plat_driver);
+}
+module_init(c_can_plat_init);
+
+static void __exit c_can_plat_exit(void)
+{
+	platform_driver_unregister(&c_can_plat_driver);
+}
+module_exit(c_can_plat_exit);
+
+MODULE_AUTHOR("Bhupesh Sharma <bhupesh.sharma@st.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Platform CAN bus driver for Bosch C_CAN controller");