we are developping a uwb (ultra wide band) network chip.
this should be a wireless 100-500 Mbps with Qos communication chip. ( bluetooth and WiFi, beware ;-)
the prototype i am working on has it's registers and rams mapped as memory on a PCI card.
i tried using /dev/mem to access it, but it didn't work. so i tried looking at examples and builded my own driver.
i am succesfull at accessing my card as a file. (/dev/uwb/0)
i was not successful at accessing it as mmapped (i can mmap it, write/read to/from it, but it does not do the real writing/reading to/from the card, and i get no errors either).
the only issue, is that when i do a read or write, even that the length of the copy_from_user or copy_to_user is 4 bytes long, it seems to read/write more than that
so if i access (read) adress 0xa00004, i get the register at 0xa00000 also read. (probably being cached)
arch is x86 (Pentium III)
any idea ?
cheers, erez.
btw, here are the main code:
static ssize_t uwb_dev_read (struct file *filp, char *buf, size_t count, loff_t * offp) { unsigned int num=(unsigned int)filp->private_data-1; unsigned long p=*offp; ssize_t ret = 0; int size;
//printk(KERN_INFO UWB "read: addr=%d, len=%d\n",(int)p,(int)count);
//printk(KERN_INFO UWB "num=%d, num_boards=%d\n",(int)num,(int)num_boards);
if (num>num_boards) return -EFAULT;
if (p>(unsigned int)mem_size) return -EFAULT;
size=MIN(count,(unsigned int)mem_size-p);
size=MIN(size,4);
//printk(KERN_INFO UWB "read addres 0x%lx..0x%lx ... ",p,p+size-1);
//printk(KERN_INFO UWB "coping to user space\n");
if (copy_to_user (buf, uwb_mem[num]+p, size))
return -EFAULT;
ret=size;
//printk(KERN_INFO UWB "done read\n");
//printk("%d bytes read \n",ret);
*offp+=ret;
return ret;
}
static ssize_t uwb_dev_write(struct file *filp, const char *buf, size_t count, loff_t * offp)
{
unsigned int num=(unsigned int)filp->private_data-1;
unsigned long p=*offp;
ssize_t ret = 0;
int size;
if (num>num_boards) return -EFAULT;
if (p>(unsigned int)mem_size) return -EFAULT;
size=MIN(count,(unsigned int)mem_size-p);
size=MIN(size,4);
if (copy_from_user (uwb_mem[num]+p, buf, size))
return -EFAULT;
ret=size; *offp+=ret;
return ret;
}static int uwb_dev_mmap(struct file * filp, struct vm_area_struct * vma)
{
unsigned int num=(unsigned int)filp->private_data-1;
//unsigned int num=0;
//unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
ssize_t ret = 0;
unsigned long prot = pgprot_val(vma->vm_page_prot);
if (boot_cpu_data.x86 > 3)
prot |= _PAGE_PCD | _PAGE_PWT;
vma->vm_page_prot = __pgprot(prot); /*
* Accessing memory above the top the kernel knows about or
* through a file pointer that was marked O_SYNC will be
* done non-cached.
*/
//if (noncached_address(offset) || (file->f_flags & O_SYNC))
// vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
/* Don't try to swap out physical pages.. */ vma->vm_flags |= VM_RESERVED;
/*
* Don't dump addresses that are not real memory to a core file.
*/
/*
if (offset >= __pa(high_memory) || (file->f_flags & O_SYNC))
vma->vm_flags |= VM_IO;
*/
vma->vm_flags |= VM_IO;if (vma->vm_end-vma->vm_start > mem_size[num]) ret= -EAGAIN;
else
if (remap_page_range(vma->vm_start, (unsigned long) uwb_mem[num],
vma->vm_end-vma->vm_start,
vma->vm_page_prot))
ret= -EAGAIN;
printk ("uwb: mmap, physical_ptr=0x%8X, size=0x%X, uwb num=%d, vm_ptr=0x%08X, ret=%d\n",(unsigned int) uwb_mem[num],(unsigned int)(vma->vm_end-vma->vm_start),(int)num,(unsigned int)vma->vm_start,(unsigned int)ret);
return ret;
}
/*
* uwb_init_one - look for and attempt to init a single UWB
*/
static int __init uwb_init_one (struct pci_dev *dev, int num)
{
int rc;
//u8 hw_status;DPRINTK ("ENTER\n");
mem_size[num]=UWB_ADDR_END(dev)-UWB_ADDR(dev)+1; uwb_mem[num] = ioremap (UWB_ADDR(dev), mem_size[num]); if (uwb_mem[num] == NULL) { printk (KERN_ERR UWB "cannot ioremap UWB Memory\n"); DPRINTK ("EXIT, returning -EBUSY\n"); rc = -EBUSY; return rc; }
//printk(KERN_INFO UWB "found addr %lX..%lX\n",UWB_ADDR(dev),UWB_ADDR_END(dev));
DPRINTK ("EXIT, returning 0\n");
return 0;
}
static int __init uwb_init (void)
{
int rc=0;
struct pci_dev *pdev;
int num=0;
int i;
char name[15];DPRINTK ("ENTER\n");
// init_MUTEX (&uwb_open_sem);
pci_for_each_dev(pdev) {
if (pci_match_device (uwb_pci_tbl, pdev) != NULL)
{
rc=uwb_init_one(pdev,num);
if (!rc) num++;
}
} if (!rc && !num)
{
DPRINTK ("EXIT, returning -ENODEV\n");
return -ENODEV;
}
if (!num)
{
printk (KERN_ERR UWB "cannot initialize board \n");
DPRINTK ("EXIT, returning %d\n", rc);
return rc;
}
num_boards=num;
printk ("uwb: %d board(s) found\n", num);
/*
rc = misc_register (&uwb_miscdev);
if (rc) {
printk (KERN_ERR UWB "cannot register misc device\n");
DPRINTK ("EXIT, returning %d\n", rc);
return rc;
}
*/ if ((rc=devfs_register_chrdev (0, UWB_NAME, &uwb_chrdev_ops))<0) {
printk ("uwb: unable to get major %d, rc=%d\n", major,rc);
unmap_all();
return -EIO;
}
major=rc;
printk ("uwb: major=%d\n", major);devdir=devfs_mk_dir (NULL, UWB_DIR , NULL);
if (NULL==devdir) {printk (KERN_INFO "unable to mkdir %s\n",UWB_DIR);};//return -EBUSY;};
for (i=0;i<num_boards;i++)
{
sprintf(name,"uwb%d",num);
handle[i]=devfs_register (devdir, "uwb", DEVFS_FL_NONE,
major, i,
S_IFCHR | S_IRUSR | S_IWUSR | S_IRGRP,
&uwb_chrdev_ops, (int *)(i+1));
if (handle[i]==0) printk (KERN_INFO "unable to register card, do manually: mknod /dev/uwb/%d c %d %d\n",i,major,i);
}
printk (KERN_INFO "IFX Uwb Mac Board driver: %d boards installed\n",num);
DPRINTK ("EXIT, returning 0\n");
return 0;
}
/*
* uwb_init - shutdown UWB module
*/
static void __exit uwb_cleanup (void)
{
int i;
DPRINTK ("ENTER\n");/*
misc_deregister (&uwb_miscdev);
*/
for (i=0;i<num_boards;i++) devfs_unregister(handle[i]);
devfs_unregister_chrdev(major, UWB_DIR);
unmap_all();
printk (KERN_INFO "IFX Uwb Mac Board driver: %d boards removed\n",num_boards);
DPRINTK ("EXIT\n");
}static int uwb_dev_open (struct inode *inode, struct file *filp)
{
//printk (KERN_INFO "open device #%d\n",MINOR(inode->i_rdev));
if (MINOR(inode->i_rdev) >= num_boards)
return -ENXIO; filp->private_data=(void *)(1+MINOR(inode->i_rdev));
MOD_INC_USE_COUNT;
return 0;
}
static int uwb_dev_release (struct inode *inode, struct file *filp) { //printk (KERN_INFO "open\n"); MOD_DEC_USE_COUNT; return 0; }
Muli Ben-Yehuda wrote:
On Mon, Oct 20, 2003 at 09:46:48PM +0200, Official Flamer/Cabal NON-Leader wrote:
Quoth Erez Doron:etc).
i am using copy_from_user and copy_to_user functions.The simplest way is to snarf a block of contiguous memory OUTside the
how do i make that physical memory non cached ?
kernel, export it and write to/read from it somehow (e.g. by mmap,
Simplest, but it's also considered a fairly ugly hack :P
Erez, what are you trying to do, and on which arch? how to make
physical memory non cached is fairly architecture dependant, AFAIK.
Cheers, Muli
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