ucmb: Put the lowlevel protocol handling into the kernel.

SVN-Revision: 14524

diff --git a/package/ucmb/src/ucmb.c b/package/ucmb/src/ucmb.c
index 4807f95ce33a41cb0b3d1f55bbe79c98ec601875..c2cb1a9c6c9bf8a56265d27b5194251ada31cacc 100644 (file)
--- a/package/ucmb/src/ucmb.c
+++ b/package/ucmb/src/ucmb.c
@@ -16,6 +16,7 @@
 #include <linux/spi/spi_gpio.h>
 #include <linux/spi/spi_bitbang.h>
 #include <linux/gfp.h>
+#include <linux/delay.h>
 
 
 #define PFX    "ucmb: "
@@ -39,12 +40,34 @@ struct ucmb {
        struct platform_device spi_gpio_pdev;
 };
 
+struct ucmb_message_hdr {
+       __le16 magic;           /* UCMB_MAGIC */
+       __le16 len;             /* Payload length (excluding header) */
+} __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 */
+};
+
+
 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,
@@ -72,6 +95,21 @@ static struct spi_driver ucmb_spi_driver = {
        .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;
+       }
+       return -EBUSY;
+}
+
 static inline struct ucmb * filp_to_ucmb(struct file *filp)
 {
        return container_of(filp->f_op, struct ucmb, mdev_fops);
@@ -83,29 +121,48 @@ static ssize_t ucmb_read(struct file *filp, char __user *user_buf,
 {
        struct ucmb *ucmb = filp_to_ucmb(filp);
        u8 *buf;
-       int err;
+       int res, err;
+       struct ucmb_message_hdr hdr;
+       struct ucmb_status status = { .magic = cpu_to_le16(UCMB_MAGIC), };
 
        err = -E2BIG;
        if (size > PAGE_SIZE)
                goto out;
+       if (size > UCMB_MAX_MSG_LEN)
+               goto out;
 
        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;
+       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 = -EFAULT;
        if (copy_to_user(user_buf, buf, size))
-               goto out_free;
+               goto out_send_status;
 
        err = 0;
 
+out_send_status:
+       status.code = err ? UCMB_STAT_ENOMEM : UCMB_STAT_OK;
+       res = spi_write(ucmb->sdev, (u8 *)&status, sizeof(status));
+       if (res && !err)
+               err = res;
 out_free:
-       __free_page((unsigned long)buf);
+       free_page((unsigned long)buf);
 out:
        return err ? err : size;
 }
@@ -117,21 +174,57 @@ static ssize_t ucmb_write(struct file *filp, const char __user *user_buf,
        struct ucmb *ucmb = filp_to_ucmb(filp);
        u8 *buf;
        int err;
+       struct ucmb_message_hdr hdr = { .magic = cpu_to_le16(UCMB_MAGIC), };
+       struct ucmb_status status;
+       struct spi_transfer spi_hdr_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(PAGE_SIZE, size);
+       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);
+
+       spi_message_init(&spi_msg);
 
-       err = spi_write(ucmb->sdev, buf, size);
+       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);
+
+       /* 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. */
+       msleep(1);
+
+       /* Get the status code. */
+       err = spi_read(ucmb->sdev, (u8 *)&status, sizeof(status));
+       if (err)
+               goto out_free;
+       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);
+       free_page((unsigned long)buf);
 out:
        return err ? err : size;
 }
@@ -187,12 +280,12 @@ static int __devinit ucmb_probe(struct platform_device *pdev)
                printk(KERN_ERR PFX "Failed to allocate SPI device\n");
                goto err_unreg_spi_gpio_pdev;
        }
-       ucmb->sdev->max_speed_hz = 5000000;
+       ucmb->sdev->max_speed_hz = 500000;
        ucmb->sdev->chip_select = 0;
        ucmb->sdev->mode = SPI_MODE_0;
        strlcpy(ucmb->sdev->modalias, "ucmb", /* We are the SPI driver. */
                sizeof(ucmb->sdev->modalias));
-       ucmb->sdev->controller_data = (void *)SPI_GPIO_NO_CHIPSELECT;
+       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");

diff --git a/package/ucmb/src/ucmb.h b/package/ucmb/src/ucmb.h
index f1a92836f86fe599dc38e40e2e1a2c5dd9777b8c..cce4e746619adef03f257558e2e080970db6231f 100644 (file)
--- a/package/ucmb/src/ucmb.h
+++ b/package/ucmb/src/ucmb.h
@@ -3,6 +3,7 @@
 
 struct ucmb_platform_data {
        const char *name;
+       unsigned long gpio_cs;
        unsigned int gpio_sck;
        unsigned int gpio_miso;
        unsigned int gpio_mosi;