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ucmb: Put the lowlevel protocol handling into the kernel.

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git-svn-id: svn://svn.openwrt.org/openwrt/trunk@14524 3c298f89-4303-0410-b956-a3cf2f4a3e73
This commit is contained in:
mb 2009-02-15 17:16:49 +00:00
parent 6d425a85a8
commit 8fa8c599e9
2 changed files with 102 additions and 8 deletions
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109
package/ucmb/src/ucmb.c
View File

@ -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);
err = spi_write(ucmb->sdev, buf, size);
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);
/* 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");

1
package/ucmb/src/ucmb.h
View File

@ -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;