+/*
+ * 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);
projects / openwrt.git / commitdiff