Re: [PATCH 1/2] net: ethernet: bgmac: init sequence bug

[Zac Schroff]

How about BCMA_IOCTL_PRESERVE_ACROSS_INIT?

On Wed, Feb 1, 2017 at 6:06 PM, RafaÅ MiÅecki <rafal@xxxxxxxxxx> wrote:
> On 02/01/2017 11:39 PM, Jon Mason wrote:
>>
>> From: Zac Schroff <zschroff@xxxxxxxxxxxx>
>>
>> Fix a bug in the 'bgmac' driver init sequence that blind writes for init
>> sequence where it should preserve most bits other than the ones it is
>> deliberately manipulating.
>>
>> Signed-off-by: Zac Schroff <zschroff@xxxxxxxxxxxx>
>> Signed-off-by: Jon Mason <jon.mason@xxxxxxxxxxxx>
>> Fixes: f6a95a24957 ("net: ethernet: bgmac: Add platform device support")
>> ---
>>  drivers/net/ethernet/broadcom/bgmac-platform.c | 10 +++++++---
>>  include/linux/bcma/bcma_regs.h                 |  1 +
>>  2 files changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/broadcom/bgmac-platform.c
>> b/drivers/net/ethernet/broadcom/bgmac-platform.c
>> index 6f736c1..9bbe05c 100644
>> --- a/drivers/net/ethernet/broadcom/bgmac-platform.c
>> +++ b/drivers/net/ethernet/broadcom/bgmac-platform.c
>> @@ -61,15 +61,19 @@ static bool platform_bgmac_clk_enabled(struct bgmac
>> *bgmac)
>>
>>  static void platform_bgmac_clk_enable(struct bgmac *bgmac, u32 flags)
>>  {
>> -       bgmac_idm_write(bgmac, BCMA_IOCTL,
>> -                       (BCMA_IOCTL_CLK | BCMA_IOCTL_FGC | flags));
>> +       u32 regval;
>> +
>> +       /* Some bits of BCMA_IOCTL set by HW/ATF & should not change */
>> +       regval = bgmac_idm_read(bgmac, BCMA_IOCTL) &
>> BCMA_IOCTL_DO_NOT_MODIFY;
>> +       regval |= ((flags & (~BCMA_IOCTL_DO_NOT_MODIFY)) |
>> BCMA_IOCTL_CLK);
>
>
> You don't need these braces around whole calculation.
> This should work the same:
> (flags & (~BCMA_IOCTL_DO_NOT_MODIFY)) | BCMA_IOCTL_CLK
>
>
>> +       bgmac_idm_write(bgmac, BCMA_IOCTL, regval | BCMA_IOCTL_FGC);
>>         bgmac_idm_read(bgmac, BCMA_IOCTL);
>>
>>         bgmac_idm_write(bgmac, BCMA_RESET_CTL, 0);
>>         bgmac_idm_read(bgmac, BCMA_RESET_CTL);
>>         udelay(1);
>>
>> -       bgmac_idm_write(bgmac, BCMA_IOCTL, (BCMA_IOCTL_CLK | flags));
>> +       bgmac_idm_write(bgmac, BCMA_IOCTL, regval);
>>         bgmac_idm_read(bgmac, BCMA_IOCTL);
>>         udelay(1);
>>  }
>> diff --git a/include/linux/bcma/bcma_regs.h
>> b/include/linux/bcma/bcma_regs.h
>> index 9986f82..41d7404 100644
>> --- a/include/linux/bcma/bcma_regs.h
>> +++ b/include/linux/bcma/bcma_regs.h
>> @@ -31,6 +31,7 @@
>>  #define  BCMA_IOCTL_CORE_BITS          0x3FFC
>>  #define  BCMA_IOCTL_PME_EN             0x4000
>>  #define  BCMA_IOCTL_BIST_EN            0x8000
>> +#define  BCMA_IOCTL_DO_NOT_MODIFY      0x7FFFFF80
>
>
> This sounds like a pretty bad name.
>
> Take a look at brcmsmac and SICF_*:
> http://lxr.free-electrons.com/source/drivers/net/wireless/broadcom/brcm80211/brcmsmac/d11.h?v=4.9#L1737
>
> Or b43 and B43_BCMA_IOCTL_*:
> http://lxr.free-electrons.com/source/drivers/net/wireless/broadcom/b43/b43.h?v=4.9#L494
>
> Both drives modify bits you marked as DO_NOT_MODIFY and they are OK.