2003-06-15 16:18:08

by Stelian Pop

[permalink] [raw]
Subject: [PATCH 2.4.21] meye driver update

Hi,

Here is my latest meye driver version, ready to be integrated
in the next -pre cycle.

The attached patch:
* replaces the pci_alloc_consistent calls with dma_alloc_coherent
because we want to do the allocations at GFP_KERNEL priority and
not GFP_ATOMIC because we request quite a bit of memory and the
allocation fails quite frequently.

It would be better to have a pci_alloc_consistent with an extra
parameter (priority) but since we haven't, and the meye driver is
supposed to work only on ix86 platforms we can safely do the
change. Moreover, in 2.4 we don't even have a dma_alloc_coherent
function, so the meye driver is carrying a local version,
backported from 2.5.

* fixes the DMA engine stop request. The hard freezes encountered
when using this driver and repeatedly opening/closing the device
have been tracked down to this particular piece of code. The new
version seems to work way better, I haven't had a single freeze
since the change.

Marcelo, please apply.

Stelian.

===== drivers/media/video/meye.h 1.7 vs edited =====
--- 1.7/drivers/media/video/meye.h Fri Feb 21 11:24:07 2003
+++ edited/drivers/media/video/meye.h Tue Jun 10 11:18:50 2003
@@ -31,7 +31,7 @@
#define _MEYE_PRIV_H_

#define MEYE_DRIVER_MAJORVERSION 1
-#define MEYE_DRIVER_MINORVERSION 6
+#define MEYE_DRIVER_MINORVERSION 7

#include <linux/config.h>
#include <linux/types.h>
===== drivers/media/video/meye.c 1.13 vs edited =====
--- 1.13/drivers/media/video/meye.c Tue Feb 18 12:31:10 2003
+++ edited/drivers/media/video/meye.c Thu Apr 17 10:23:00 2003
@@ -161,6 +161,34 @@
}
}

+/****************************************************************************/
+/* dma_alloc_coherent / dma_free_coherent ported from 2.5 */
+/****************************************************************************/
+
+void *dma_alloc_coherent(struct pci_dev *dev, size_t size,
+ dma_addr_t *dma_handle, int gfp)
+{
+ void *ret;
+ /* ignore region specifiers */
+ gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
+
+ if (dev == NULL || ((u32)dev->dma_mask < 0xffffffff))
+ gfp |= GFP_DMA;
+ ret = (void *)__get_free_pages(gfp, get_order(size));
+
+ if (ret != NULL) {
+ memset(ret, 0, size);
+ *dma_handle = virt_to_phys(ret);
+ }
+ return ret;
+}
+
+void dma_free_coherent(struct pci_dev *dev, size_t size,
+ void *vaddr, dma_addr_t dma_handle)
+{
+ free_pages((unsigned long)vaddr, get_order(size));
+}
+
/* return a page table pointing to N pages of locked memory */
static int ptable_alloc(void) {
u32 *pt;
@@ -168,9 +196,10 @@

memset(meye.mchip_ptable, 0, sizeof(meye.mchip_ptable));

- meye.mchip_ptable[MCHIP_NB_PAGES] = pci_alloc_consistent(meye.mchip_dev,
- PAGE_SIZE,
- &meye.mchip_dmahandle);
+ meye.mchip_ptable[MCHIP_NB_PAGES] = dma_alloc_coherent(meye.mchip_dev,
+ PAGE_SIZE,
+ &meye.mchip_dmahandle,
+ GFP_KERNEL);
if (!meye.mchip_ptable[MCHIP_NB_PAGES]) {
meye.mchip_dmahandle = 0;
return -1;
@@ -178,16 +207,17 @@

pt = (u32 *)meye.mchip_ptable[MCHIP_NB_PAGES];
for (i = 0; i < MCHIP_NB_PAGES; i++) {
- meye.mchip_ptable[i] = pci_alloc_consistent(meye.mchip_dev,
- PAGE_SIZE,
- pt);
+ meye.mchip_ptable[i] = dma_alloc_coherent(meye.mchip_dev,
+ PAGE_SIZE,
+ pt,
+ GFP_KERNEL);
if (!meye.mchip_ptable[i]) {
int j;
pt = (u32 *)meye.mchip_ptable[MCHIP_NB_PAGES];
for (j = 0; j < i; ++j) {
- pci_free_consistent(meye.mchip_dev,
- PAGE_SIZE,
- meye.mchip_ptable[j], *pt);
+ dma_free_coherent(meye.mchip_dev,
+ PAGE_SIZE,
+ meye.mchip_ptable[j], *pt);
pt++;
}
meye.mchip_dmahandle = 0;
@@ -205,17 +235,17 @@
pt = (u32 *)meye.mchip_ptable[MCHIP_NB_PAGES];
for (i = 0; i < MCHIP_NB_PAGES; i++) {
if (meye.mchip_ptable[i])
- pci_free_consistent(meye.mchip_dev,
- PAGE_SIZE,
- meye.mchip_ptable[i], *pt);
+ dma_free_coherent(meye.mchip_dev,
+ PAGE_SIZE,
+ meye.mchip_ptable[i], *pt);
pt++;
}

if (meye.mchip_ptable[MCHIP_NB_PAGES])
- pci_free_consistent(meye.mchip_dev,
- PAGE_SIZE,
- meye.mchip_ptable[MCHIP_NB_PAGES],
- meye.mchip_dmahandle);
+ dma_free_coherent(meye.mchip_dev,
+ PAGE_SIZE,
+ meye.mchip_ptable[MCHIP_NB_PAGES],
+ meye.mchip_dmahandle);

memset(meye.mchip_ptable, 0, sizeof(meye.mchip_ptable));
meye.mchip_dmahandle = 0;
@@ -614,25 +644,25 @@
/* stop any existing HIC action and wait for any dma to complete then
reset the dma engine */
static void mchip_hic_stop(void) {
- int i = 0;
+ int i, j;

meye.mchip_mode = MCHIP_HIC_MODE_NOOP;
- if (!(mchip_read(MCHIP_HIC_STATUS) & MCHIP_HIC_STATUS_BUSY))
+ if (!(mchip_read(MCHIP_HIC_STATUS) & MCHIP_HIC_STATUS_BUSY))
return;
- mchip_set(MCHIP_HIC_CMD, MCHIP_HIC_CMD_STOP);
- mchip_delay(MCHIP_HIC_CMD, 0);
- while (!mchip_delay(MCHIP_HIC_STATUS, MCHIP_HIC_STATUS_IDLE)) {
- /* resetting HIC */
+ for (i = 0; i < 20; ++i) {
mchip_set(MCHIP_HIC_CMD, MCHIP_HIC_CMD_STOP);
mchip_delay(MCHIP_HIC_CMD, 0);
+ for (j = 0; j < 100; ++j) {
+ if (mchip_delay(MCHIP_HIC_STATUS, MCHIP_HIC_STATUS_IDLE))
+ return;
+ wait_ms(1);
+ }
+ printk(KERN_ERR "meye: need to reset HIC!\n");
+
mchip_set(MCHIP_HIC_CTL, MCHIP_HIC_CTL_SOFT_RESET);
wait_ms(250);
- if (i++ > 20) {
- printk(KERN_ERR "meye: resetting HIC hanged!\n");
- break;
- }
}
- wait_ms(100);
+ printk(KERN_ERR "meye: resetting HIC hanged!\n");
}

/****************************************************************************/
@@ -1392,6 +1422,8 @@

mchip_hic_stop();

+ mchip_dma_free();
+
/* disable interrupts */
mchip_set(MCHIP_MM_INTA, 0x0);

@@ -1403,8 +1435,6 @@
pci_resource_len(meye.mchip_dev, 0));

pci_disable_device(meye.mchip_dev);
-
- mchip_dma_free();

if (meye.grab_fbuffer)
rvfree(meye.grab_fbuffer, gbuffers*gbufsize);


--
Stelian Pop <[email protected]>


2003-06-15 16:53:51

by Michael Buesch

[permalink] [raw]
Subject: Re: [PATCH 2.4.21] meye driver update

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Hash: SHA1

On Sunday 15 June 2003 18:31, Stelian Pop wrote:
> Hi,

Hi Stelian,

> +void dma_free_coherent(struct pci_dev *dev, size_t size,
^^^^^^^^^^^^^^^^^^^
> + void *vaddr, dma_addr_t dma_handle)
^^^^^^^^^^^^^^^^^^^^^
Why do you define these unused parameters?
> +{
> + free_pages((unsigned long)vaddr, get_order(size));
> +}

And why are they defined in 2.5, too, althought unused.
Is there some reason?

- --
Regards Michael B?sch
http://www.8ung.at/tuxsoft
19:00:48 up 2:45, 2 users, load average: 1.37, 1.13, 1.08

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2003-06-15 21:15:53

by Stelian Pop

[permalink] [raw]
Subject: Re: [PATCH 2.4.21] meye driver update

On Sun, Jun 15, 2003 at 07:06:56PM +0200, Michael Buesch wrote:

> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On Sunday 15 June 2003 18:31, Stelian Pop wrote:
> > Hi,
>
> Hi Stelian,
>
> > +void dma_free_coherent(struct pci_dev *dev, size_t size,
> ^^^^^^^^^^^^^^^^^^^
> > + void *vaddr, dma_addr_t dma_handle)
> ^^^^^^^^^^^^^^^^^^^^^
> Why do you define these unused parameters?

Because it's backported from 2.5, and I took it as it, without
editing.

> > +{
> > + free_pages((unsigned long)vaddr, get_order(size));
> > +}
>
> And why are they defined in 2.5, too, althought unused.
> Is there some reason?

Unused of ix86 because bus addresses are the same as virtual addresses.
This is not however the case on other architetures, see
Documentation/DMA-mapping.txt.

Stelian.
--
Stelian Pop <[email protected]>

2003-06-16 05:51:30

by Stelian Pop

[permalink] [raw]
Subject: Re: [PATCH 2.4.21] meye driver update

On Sun, Jun 15, 2003 at 11:29:35PM +0200, Stelian Pop wrote:
>
> Unused of ix86 because bus addresses are the same as virtual addresses.

Of course I meant that bus addresses are the same as the _physical_
addresses...

I should really sleep first, then reply, not the other way around...

Stelian.
--
Stelian Pop <[email protected]>
Alcove - http://www.alcove.com

2003-06-16 14:57:20

by Michael Buesch

[permalink] [raw]
Subject: Re: [PATCH 2.4.21] meye driver update

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On Sunday 15 June 2003 23:29, Stelian Pop wrote:
> On Sun, Jun 15, 2003 at 07:06:56PM +0200, Michael Buesch wrote:
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> > On Sunday 15 June 2003 18:31, Stelian Pop wrote:
> > > Hi,
> >
> > Hi Stelian,
> >
> > > +void dma_free_coherent(struct pci_dev *dev, size_t size,
> >
> > ^^^^^^^^^^^^^^^^^^^
> >
> > > + void *vaddr, dma_addr_t dma_handle)
> >
> > ^^^^^^^^^^^^^^^^^^^^^
> > Why do you define these unused parameters?
>
> Because it's backported from 2.5, and I took it as it, without
> editing.
>
> > > +{
> > > + free_pages((unsigned long)vaddr, get_order(size));
> > > +}
> >
> > And why are they defined in 2.5, too, althought unused.
> > Is there some reason?
>
> Unused of ix86 because bus addresses are the same as virtual addresses.
> This is not however the case on other architetures, see
> Documentation/DMA-mapping.txt.

Yes, I now understand, why it is in 2.5, but isn't it better,
to remove these parameters from your patch, because it is only
a local copy in your driver and not used by any other drivers.
And your driver is (if I didn't miss something) for running on
i386 only; there is no other version of this function for
other architectures, that need these parameters.
So wouldn't it be better to simply remove them, because
they are completely useless. IMHO their
just confusing.

>
> Stelian.

- --
Regards Michael B?sch
http://www.8ung.at/tuxsoft
16:49:26 up 8 min, 1 user, load average: 1.07, 0.96, 0.49

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2003-06-16 15:23:00

by Stelian Pop

[permalink] [raw]
Subject: Re: [PATCH 2.4.21] meye driver update

On Mon, Jun 16, 2003 at 04:54:41PM +0200, Michael Buesch wrote:

> > Unused of ix86 because bus addresses are the same as virtual addresses.
> > This is not however the case on other architetures, see
> > Documentation/DMA-mapping.txt.
>
> Yes, I now understand, why it is in 2.5, but isn't it better,
> to remove these parameters from your patch, because it is only
> a local copy in your driver and not used by any other drivers.
> And your driver is (if I didn't miss something) for running on
> i386 only; there is no other version of this function for
> other architectures, that need these parameters.
> So wouldn't it be better to simply remove them, because
> they are completely useless. IMHO their
> just confusing.

No, I hope that the DMA allocation function will be backported in the
near future from 2.5 into 2.4. If I get some time, I may even do it
myself and propose a patch.

And when it's done, I'll just have to remove the two definitions
without changing anything in my code and it will just work.

Besides, having two versions (2.4 and 2.5) which don't diverge to much
is much easier for the maintainer.

Stelian.
--
Stelian Pop <[email protected]>
Alcove - http://www.alcove.com