Re: [PATCH] staging: comedi: jr3_pci: add __iomem tags

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On 2012-09-24 17:38, H Hartley Sweeten wrote:
On Monday, September 24, 2012 7:20 AM, Ian Abbott wrote:
Tag pointers to remapped I/O memory with `__iomem` and remove the
`volatile` qualifiers.  Fix the single place in `jr3_pci_attach()` where
an I/O memory pointer is being dereferenced directly to use the
appropriate I/O memory access function.

Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>

Ian,

I don't think this is _completely_ right.

---
  drivers/staging/comedi/drivers/jr3_pci.c | 35 ++++++++++++++++----------------
  drivers/staging/comedi/drivers/jr3_pci.h | 12 +++++------
  2 files changed, 24 insertions(+), 23 deletions(-)

diff --git a/drivers/staging/comedi/drivers/jr3_pci.c b/drivers/staging/comedi/drivers/jr3_pci.c
index 360107c..5b193ef 100644
--- a/drivers/staging/comedi/drivers/jr3_pci.c
+++ b/drivers/staging/comedi/drivers/jr3_pci.c
@@ -62,7 +62,7 @@ struct jr3_pci_dev_private {

  	struct pci_dev *pci_dev;
  	int pci_enabled;
-	volatile struct jr3_t *iobase;
+	struct jr3_t __iomem *iobase;

The ioremap'ed pci base address is a 'void __iomem *'. This is casting
it to a 'struct jr3_t __iomem *'. Which still leaves this driver with the
goofy indirect i/o using the struct instead of normal read[lwb]/write[lwb]
calls.

Changing the iobase variable in the struct like you have done may
get rid of the sparse warning but this drive is still pretty darn confusing.

I think the struct itself needs to be removed an replaced with #define's
for the memory map of the card. Then all the struct i/o access can be
replaced with read*/write* calls as appropriate.

It is actually using readl() and writel() throughout (mostly via its `get_s16()`, `set_s16()`, get_u16()` and `set_u16()` functions), but yes, the way the register offsets is determined is a bit goofy!

--
-=( Ian Abbott @ MEV Ltd.    E-mail: <abbotti@xxxxxxxxx>        )=-
-=( Tel: +44 (0)161 477 1898   FAX: +44 (0)161 718 3587         )=-
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