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SubjectRe: [PATCH 1/2] net: ethernet: bgmac: init sequence bug
How about BCMA_IOCTL_PRESERVE_ACROSS_INIT?

On Wed, Feb 1, 2017 at 6:06 PM, Rafał Miłecki <rafal@milecki.pl> wrote:
> On 02/01/2017 11:39 PM, Jon Mason wrote:
>>
>> From: Zac Schroff <zschroff@broadcom.com>
>>
>> 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@broadcom.com>
>> Signed-off-by: Jon Mason <jon.mason@broadcom.com>
>> 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.

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