Hi Wolfgang,
Weird, I would have thought the usage of in_be out_be macro ensured
that. But after checking, they only include a isync instruction which
doesn't guarantee memory access will be done while mb() uses sync that
does guarantee that.
Any one can comment on that ? Wasn't the purpose of the in_be out_be to
ensure that ?
Sylvain
Wolfgang Denk wrote:
> Hello,
>
> the following patch is against the current 2.6 kernel.org tree
> (commit f96c3bbe91117402f13119ce9e609db9087ed58f):
>
> As a prerequisite for a working system, the following two poatches
> are needed, too:
>
> http://patchwork.ozlabs.org/linuxppc/patch?id=2018
> http://patchwork.ozlabs.org/linuxppc/patch?id=2017
>
>
> !-------------------------------------------------------------flip-
>
> [patch] making PCI work in the MPC5200
> Patch by Alessandro Rubini, 08 Oct 2005
>
> Make PCI work in 2.6 with the IceCube 5200.
>
> Without the memory barriers all PCI config reads returned 0xffffffff
> (actually, there may be more mb() than needed). Using wmb(); was not
> enough to be able to read configuration registers.
>
> Signed-off by Alessandro Rubini <rubini at gnudd.com>
> Signed-off by Wolfgang Denk <wd at denx.de>
>
> ---
> commit cdd7fdf10b3cbb7eb82cacc7ba5dba3553020f49
> tree 97d045b44c87c00a4b3fe5bca57b479be87e68b6
> parent 509b5c9fcbfe7fcae7d4f98946e4dc9794d68645
> author Wolfgang Denk <wd at pollux.denx.de> Sat, 08 Oct 2005 22:41:53 +0200
> committer Wolfgang Denk <wd at pollux.denx.de> Sat, 08 Oct 2005 22:41:53 +0200
>
> arch/ppc/syslib/mpc52xx_pci.c | 4 ++++
> 1 files changed, 4 insertions(+), 0 deletions(-)
>
> diff --git a/arch/ppc/syslib/mpc52xx_pci.c b/arch/ppc/syslib/mpc52xx_pci.c
> --- a/arch/ppc/syslib/mpc52xx_pci.c
> +++ b/arch/ppc/syslib/mpc52xx_pci.c
> @@ -39,6 +39,7 @@ mpc52xx_pci_read_config(struct pci_bus *
> ((bus->number - hose->bus_offset) << 16) |
> (devfn << 8) |
> (offset & 0xfc));
> + mb();
>
> value = in_le32(hose->cfg_data);
>
> @@ -70,6 +71,7 @@ mpc52xx_pci_write_config(struct pci_bus
> ((bus->number - hose->bus_offset) << 16) |
> (devfn << 8) |
> (offset & 0xfc));
> + mb();
>
> if (len != 4) {
> value = in_le32(hose->cfg_data);
> @@ -80,9 +82,11 @@ mpc52xx_pci_write_config(struct pci_bus
>
> value &= ~mask;
> val = value | ((val << offset) & mask);
> + mb();
> }
>
> out_le32(hose->cfg_data, val);
> + mb();
>
> out_be32(hose->cfg_addr, 0);
>
>
>
>
> !-------------------------------------------------------------flip-
>
>
>
> Best regards,
>
> Wolfgang Denk
>
