+++ /dev/null
-/*
- * 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);
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