ucmb: Fix the lowlevel protocol

SVN-Revision: 14549

3 files changed, 506 insertions, 0 deletions

diff --git a/package/ucmb/driver/Makefile b/package/ucmb/driver/Makefile
new file mode 100644
index 0000000000..a232a4a096
--- /dev/null
+++ b/package/ucmb/driver/Makefile
@@ -0,0 +1 @@
+obj-m := ucmb.o
diff --git a/package/ucmb/driver/ucmb.c b/package/ucmb/driver/ucmb.c
new file mode 100644
index 0000000000..276553ada5
--- /dev/null
+++ b/package/ucmb/driver/ucmb.c
@@ -0,0 +1,467 @@
+/*
+ * Microcontroller Message Bus
+ *
+ * Copyright (c) 2009 Michael Buesch <mb@bu3sch.de>
+ *
+ * Licensed under the GNU/GPL. See COPYING for details.
+ */
+
+#include "ucmb.h"
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/miscdevice.h>
+#include <linux/fs.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_gpio.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/gfp.h>
+#include <linux/delay.h>
+#include <linux/crc16.h>
+
+
+#define PFX	"ucmb: "
+
+#define DEBUG
+
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Microcontroller Message Bus");
+MODULE_AUTHOR("Michael Buesch");
+
+
+struct ucmb {
+	unsigned int msg_delay_ms;
+
+	/* Misc character device driver */
+	struct miscdevice mdev;
+	struct file_operations mdev_fops;
+
+	/* SPI driver */
+	struct spi_device *sdev;
+
+	/* SPI-GPIO driver */
+	struct spi_gpio_platform_data spi_gpio_pdata;
+	struct platform_device spi_gpio_pdev;
+};
+
+struct ucmb_message_hdr {
+	__le16 magic;		/* UCMB_MAGIC */
+	__le16 len;		/* Payload length (excluding header) */
+} __attribute__((packed));
+
+struct ucmb_message_footer {
+	__le16 crc;		/* CRC of the header + payload. */
+} __attribute__((packed));
+
+struct ucmb_status {
+	__le16 magic;		/* UCMB_MAGIC */
+	__le16 code;		/* enum ucmb_status_code */
+} __attribute__((packed));
+
+#define UCMB_MAGIC		0x1337
+#define UCMB_MAX_MSG_LEN	0x200
+
+enum ucmb_status_code {
+	UCMB_STAT_OK = 0,
+	UCMB_STAT_EPROTO,	/* Protocol format error */
+	UCMB_STAT_ENOMEM,	/* Out of memory */
+	UCMB_STAT_E2BIG,	/* Message too big */
+	UCMB_STAT_ECRC,		/* CRC error */
+};
+
+
+static int ucmb_spi_busnum_count = 1337;
+
+
+static struct ucmb_platform_data ucmb_list[] = {
+	{ //FIXME don't define it here.
+		.name		= "ucmb",
+		.gpio_cs	= 3,
+		.gpio_sck	= 0,
+		.gpio_miso	= 1,
+		.gpio_mosi	= 2,
+		.mode		= SPI_MODE_0,
+		.max_speed_hz	= 128000, /* Hz */
+		.msg_delay_ms	= 1, /* mS */
+	},
+};
+
+
+static int __devinit ucmb_spi_probe(struct spi_device *sdev)
+{
+	return 0;
+}
+
+static int __devexit ucmb_spi_remove(struct spi_device *sdev)
+{
+	return 0;
+}
+
+static struct spi_driver ucmb_spi_driver = {
+	.driver		= {
+		.name	= "ucmb",
+		.bus	= &spi_bus_type,
+		.owner	= THIS_MODULE,
+	},
+	.probe		= ucmb_spi_probe,
+	.remove		= __devexit_p(ucmb_spi_remove),
+};
+
+static int ucmb_status_code_to_errno(enum ucmb_status_code code)
+{
+	switch (code) {
+	case UCMB_STAT_OK:
+		return 0;
+	case UCMB_STAT_EPROTO:
+		return -EPROTO;
+	case UCMB_STAT_ENOMEM:
+		return -ENOMEM;
+	case UCMB_STAT_E2BIG:
+		return -E2BIG;
+	case UCMB_STAT_ECRC:
+		return -EBADMSG;
+	}
+	return -EBUSY;
+}
+
+static inline struct ucmb * filp_to_ucmb(struct file *filp)
+{
+	return container_of(filp->f_op, struct ucmb, mdev_fops);
+}
+
+static ssize_t ucmb_read(struct file *filp, char __user *user_buf,
+			 size_t size, loff_t *offp)
+{
+	struct ucmb *ucmb = filp_to_ucmb(filp);
+	u8 *buf;
+	int res, err;
+	struct ucmb_message_hdr hdr;
+	struct ucmb_message_footer footer;
+	struct ucmb_status status = { .magic = cpu_to_le16(UCMB_MAGIC), };
+	u16 crc = 0xFFFF;
+
+	size = min_t(size_t, size, PAGE_SIZE);
+
+	err = -ENOMEM;
+	buf = (char *)__get_free_page(GFP_KERNEL);
+	if (!buf)
+		goto out;
+
+	err = spi_read(ucmb->sdev, (u8 *)&hdr, sizeof(hdr));
+	if (err)
+		goto out_free;
+#ifdef DEBUG
+	printk(KERN_DEBUG PFX "Received message header 0x%04X 0x%04X\n",
+	       le16_to_cpu(hdr.magic), le16_to_cpu(hdr.len));
+#endif
+	err = -EPROTO;
+	if (hdr.magic != cpu_to_le16(UCMB_MAGIC))
+		goto out_free;
+	err = -ENOBUFS;
+	if (size < le16_to_cpu(hdr.len))
+		goto out_free;
+	size = le16_to_cpu(hdr.len);
+	err = spi_read(ucmb->sdev, buf, size);
+	if (err)
+		goto out_free;
+	err = spi_read(ucmb->sdev, (u8 *)&footer, sizeof(footer));
+	if (err)
+		goto out_free;
+
+	crc = crc16(crc, &hdr, sizeof(hdr));
+	crc = crc16(crc, buf, size);
+	crc ^= 0xFFFF;
+	if (crc != le16_to_cpu(footer.crc)) {
+		err = -EPROTO;
+		status.code = UCMB_STAT_ECRC;
+		goto out_send_status;
+	}
+
+	if (copy_to_user(user_buf, buf, size)) {
+		err = -EFAULT;
+		status.code = UCMB_STAT_ENOMEM;
+		goto out_send_status;
+	}
+
+	status.code = UCMB_STAT_OK;
+	err = 0;
+
+out_send_status:
+	res = spi_write(ucmb->sdev, (u8 *)&status, sizeof(status));
+	if (res && !err)
+		err = res;
+out_free:
+	free_page((unsigned long)buf);
+out:
+	return err ? err : size;
+}
+
+static ssize_t ucmb_write(struct file *filp, const char __user *user_buf,
+			  size_t size, loff_t *offp)
+{
+	struct ucmb *ucmb = filp_to_ucmb(filp);
+	u8 *buf;
+	int err;
+	struct ucmb_message_hdr hdr = { .magic = cpu_to_le16(UCMB_MAGIC), };
+	struct ucmb_message_footer footer = { .crc = 0xFFFF, };
+	struct ucmb_status status;
+	struct spi_transfer spi_hdr_xfer;
+	struct spi_transfer spi_footer_xfer;
+	struct spi_transfer spi_data_xfer;
+	struct spi_message spi_msg;
+
+	err = -ENOMEM;
+	buf = (char *)__get_free_page(GFP_KERNEL);
+	if (!buf)
+		goto out;
+
+	size = min_t(size_t, PAGE_SIZE, size);
+	size = min_t(size_t, UCMB_MAX_MSG_LEN, size);
+	err = -EFAULT;
+	if (copy_from_user(buf, user_buf, size))
+		goto out_free;
+	hdr.len = cpu_to_le16(size);
+
+	footer.crc = crc16(footer.crc, &hdr, sizeof(hdr));
+	footer.crc = crc16(footer.crc, buf, size);
+	footer.crc ^= 0xFFFF;
+
+	spi_message_init(&spi_msg);
+
+	memset(&spi_hdr_xfer, 0, sizeof(spi_hdr_xfer));
+	spi_hdr_xfer.tx_buf = &hdr;
+	spi_hdr_xfer.len = sizeof(hdr);
+	spi_message_add_tail(&spi_hdr_xfer, &spi_msg);
+
+	memset(&spi_data_xfer, 0, sizeof(spi_data_xfer));
+	spi_data_xfer.tx_buf = buf;
+	spi_data_xfer.len = size;
+	spi_message_add_tail(&spi_data_xfer, &spi_msg);
+
+	memset(&spi_footer_xfer, 0, sizeof(spi_footer_xfer));
+	spi_footer_xfer.tx_buf = &footer;
+	spi_footer_xfer.len = sizeof(footer);
+	spi_message_add_tail(&spi_footer_xfer, &spi_msg);
+
+	/* Send the message, including header. */
+	err = spi_sync(ucmb->sdev, &spi_msg);
+	if (err)
+		goto out_free;
+
+	/* The microcontroller deserves some time to process the message. */
+	if (ucmb->msg_delay_ms)
+		msleep(ucmb->msg_delay_ms);
+
+	/* Get the status code. */
+	err = spi_read(ucmb->sdev, (u8 *)&status, sizeof(status));
+	if (err)
+		goto out_free;
+#ifdef DEBUG
+	printk(KERN_DEBUG PFX "Sent message. Status report: 0x%04X 0x%04X\n",
+	       le16_to_cpu(status.magic), le16_to_cpu(status.code));
+#endif
+	err = -EPROTO;
+	if (status.magic != cpu_to_le16(UCMB_MAGIC))
+		goto out_free;
+	err = ucmb_status_code_to_errno(le16_to_cpu(status.code));
+	if (err)
+		goto out_free;
+
+out_free:
+	free_page((unsigned long)buf);
+out:
+	return err ? err : size;
+}
+
+static int __devinit ucmb_probe(struct platform_device *pdev)
+{
+	struct ucmb_platform_data *pdata;
+	struct ucmb *ucmb;
+	int err;
+	const int bus_num = ucmb_spi_busnum_count++;
+	struct spi_bitbang *bb;
+
+	pdata = pdev->dev.platform_data;
+	if (!pdata)
+		return -ENXIO;
+
+	ucmb = kzalloc(sizeof(struct ucmb), GFP_KERNEL);
+	if (!ucmb)
+		return -ENOMEM;
+	ucmb->msg_delay_ms = pdata->msg_delay_ms;
+
+	/* Create the SPI GPIO bus master. */
+
+#ifdef CONFIG_SPI_GPIO_MODULE
+	err = request_module("spi_gpio");
+	if (err)
+		printk(KERN_WARNING PFX "Failed to request spi_gpio module\n");
+#endif /* CONFIG_SPI_GPIO_MODULE */
+
+	ucmb->spi_gpio_pdata.sck = pdata->gpio_sck;
+	ucmb->spi_gpio_pdata.mosi = pdata->gpio_mosi;
+	ucmb->spi_gpio_pdata.miso = pdata->gpio_miso;
+	ucmb->spi_gpio_pdata.num_chipselect = 1;
+
+	ucmb->spi_gpio_pdev.name = "spi_gpio";
+	ucmb->spi_gpio_pdev.id = bus_num;
+	ucmb->spi_gpio_pdev.dev.platform_data = &ucmb->spi_gpio_pdata;
+
+	err = platform_device_register(&ucmb->spi_gpio_pdev);
+	if (err) {
+		printk(KERN_ERR PFX "Failed to register SPI-GPIO platform device\n");
+		goto err_free_ucmb;
+	}
+	bb = platform_get_drvdata(&ucmb->spi_gpio_pdev);
+	if (!bb || !bb->master) {
+		printk(KERN_ERR PFX "No bitbanged master device found.\n");
+		goto err_unreg_spi_gpio_pdev;
+	}
+
+	/* Create the SPI device. */
+
+	ucmb->sdev = spi_alloc_device(bb->master);
+	if (!ucmb->sdev) {
+		printk(KERN_ERR PFX "Failed to allocate SPI device\n");
+		goto err_unreg_spi_gpio_pdev;
+	}
+	ucmb->sdev->max_speed_hz = pdata->max_speed_hz;
+	ucmb->sdev->chip_select = 0;
+	ucmb->sdev->mode = pdata->mode;
+	strlcpy(ucmb->sdev->modalias, "ucmb", /* We are the SPI driver. */
+		sizeof(ucmb->sdev->modalias));
+	ucmb->sdev->controller_data = (void *)pdata->gpio_cs;
+	err = spi_add_device(ucmb->sdev);
+	if (err) {
+		printk(KERN_ERR PFX "Failed to add SPI device\n");
+		goto err_free_spi_device;
+	}
+
+	/* Create the Misc char device. */
+
+	ucmb->mdev.minor = MISC_DYNAMIC_MINOR;
+	ucmb->mdev.name = pdata->name;
+	ucmb->mdev.parent = &pdev->dev;
+	ucmb->mdev_fops.read = ucmb_read;
+	ucmb->mdev_fops.write = ucmb_write;
+	ucmb->mdev.fops = &ucmb->mdev_fops;
+
+	err = misc_register(&ucmb->mdev);
+	if (err) {
+		printk(KERN_ERR PFX "Failed to register miscdev %s\n",
+		       ucmb->mdev.name);
+		goto err_unreg_spi_device;
+	}
+
+	platform_set_drvdata(pdev, ucmb);
+
+	printk(KERN_INFO PFX "Registered message bus \"%s\"\n", pdata->name);
+
+	return 0;
+
+err_unreg_spi_device:
+	spi_unregister_device(ucmb->sdev);
+err_free_spi_device:
+	spi_dev_put(ucmb->sdev);
+err_unreg_spi_gpio_pdev:
+	platform_device_unregister(&ucmb->spi_gpio_pdev);
+err_free_ucmb:
+	kfree(ucmb);
+
+	return err;
+}
+
+static int __devexit ucmb_remove(struct platform_device *pdev)
+{
+	struct ucmb *ucmb = platform_get_drvdata(pdev);
+	int err;
+
+	err = misc_deregister(&ucmb->mdev);
+	if (err) {
+		printk(KERN_ERR PFX "Failed to unregister miscdev %s\n",
+		       ucmb->mdev.name);
+	}
+	spi_unregister_device(ucmb->sdev);
+	spi_dev_put(ucmb->sdev);
+	platform_device_unregister(&ucmb->spi_gpio_pdev);
+
+	kfree(ucmb);
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+static struct platform_driver ucmb_driver = {
+	.driver		= {
+		.name	= "ucmb",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= ucmb_probe,
+	.remove		= __devexit_p(ucmb_probe),
+};
+
+static int ucmb_modinit(void)
+{
+	struct ucmb_platform_data *pdata;
+	struct platform_device *pdev;
+	int err, i;
+
+	printk(KERN_INFO "Microcontroller message bus driver\n");
+
+	err = platform_driver_register(&ucmb_driver);
+	if (err) {
+		printk(KERN_ERR PFX "Failed to register platform driver\n");
+		return err;
+	}
+	err = spi_register_driver(&ucmb_spi_driver);
+	if (err) {
+		printk(KERN_ERR PFX "Failed to register SPI driver\n");
+		platform_driver_unregister(&ucmb_driver);
+		return err;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(ucmb_list); i++) {
+		pdata = &ucmb_list[i];
+
+		pdev = platform_device_alloc("ucmb", i);
+		if (!pdev) {
+			printk(KERN_ERR PFX "Failed to allocate platform device.\n");
+			break;
+		}
+		err = platform_device_add_data(pdev, pdata, sizeof(*pdata));
+		if (err) {
+			printk(KERN_ERR PFX "Failed to add platform data.\n");
+			platform_device_put(pdev);
+			break;
+		}
+		err = platform_device_add(pdev);
+		if (err) {
+			printk(KERN_ERR PFX "Failed to register platform device.\n");
+			platform_device_put(pdev);
+			break;
+		}
+		pdata->pdev = pdev;
+	}
+
+	return 0;
+}
+module_init(ucmb_modinit);
+
+static void ucmb_modexit(void)
+{
+	struct ucmb_platform_data *pdata;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ucmb_list); i++) {
+		pdata = &ucmb_list[i];
+
+		if (pdata->pdev) {
+			platform_device_unregister(pdata->pdev);
+			platform_device_put(pdata->pdev);
+		}
+	}
+	spi_unregister_driver(&ucmb_spi_driver);
+	platform_driver_unregister(&ucmb_driver);
+}
+module_exit(ucmb_modexit);
diff --git a/package/ucmb/driver/ucmb.h b/package/ucmb/driver/ucmb.h
new file mode 100644
index 0000000000..94fdc6420e
--- /dev/null
+++ b/package/ucmb/driver/ucmb.h
@@ -0,0 +1,38 @@
+#ifndef LINUX_UCMB_H_
+#define LINUX_UCMB_H_
+
+#include <linux/types.h>
+
+/**
+ * struct ucmb_platform_data - UCMB device descriptor
+ *
+ * @name:		The name of the device. This will also be the name of
+ *			the misc char device.
+ *
+ * @gpio_cs:		The chipselect GPIO pin. Can be SPI_GPIO_NO_CHIPSELECT.
+ * @gpio_sck:		The clock GPIO pin.
+ * @gpio_miso:		The master-in slave-out GPIO pin.
+ * @gpio_mosi:		The master-out slave-in GPIO pin.
+ *
+ * @mode:		The SPI bus mode. SPI_MODE_*
+ * @max_speed_hz:	The bus speed, in Hz. If zero the speed is not limited.
+ * @msg_delay_ms:	The message delay time, in milliseconds.
+ *			This is the time the microcontroller takes to process
+ *			one message.
+ */
+struct ucmb_platform_data {
+	const char *name;
+
+	unsigned long gpio_cs;
+	unsigned int gpio_sck;
+	unsigned int gpio_miso;
+	unsigned int gpio_mosi;
+
+	u8 mode;
+	u32 max_speed_hz;
+	unsigned int msg_delay_ms;
+
+	struct platform_device *pdev; /* internal */
+};
+
+#endif /* LINUX_UCMB_H_ */