diff options
Diffstat (limited to 'package/ucmb/driver/ucmb.c')
| -rw-r--r-- | package/ucmb/driver/ucmb.c | 467 |
1 files changed, 467 insertions, 0 deletions
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); |