diff mbox

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

Message ID 1485988752-21030-2-git-send-email-jon.mason@broadcom.com
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Jon Mason Feb. 1, 2017, 10:39 p.m. UTC 
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(-)

Comments

Rafał Miłecki Feb. 1, 2017, 11:06 p.m. UTC | #1 
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.
Zac Schroff Feb. 2, 2017, 12:31 a.m. UTC | #2 
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.
Sergei Shtylyov Feb. 2, 2017, 9:47 a.m. UTC | #3 
Hello!

On 2/2/2017 1:39 AM, 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);

    The innermost parens aren't necessary. And the outermost as well.

[...]

MBR, Sergei
Jon Mason Feb. 2, 2017, 6:54 p.m. UTC | #4 
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

Fair enough

>
>
>> +       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.

Name change coming

> 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.

I think the point Zac was trying to make is that this is changing bits
that aren't meaning to be modified.  We should only be flipping the
bits necessary to enable the clocks, etc.  Bootloaders, etc might be
setting bits (and in our case they are) which are being removed
forcing it to a predefined value.

Thanks,
Jon
Rafał Miłecki Feb. 2, 2017, 8:15 p.m. UTC | #5 
On 2017-02-02 01:31, Zac Schroff wrote:
> How about BCMA_IOCTL_PRESERVE_ACROSS_INIT?

I think wireless drivers may still set some these bits during init.

I've a simpler idea: make it bgmac specific. Call it sth like
BGMAC_BCMA_IOCTL_PRESERVE
BGMAC_BCMA_IOCTL_RESERVED
BGMAC_BCMA_IOCTL_DONT_TOUCH
Jon Mason Feb. 2, 2017, 8:20 p.m. UTC | #6 
On Thu, Feb 2, 2017 at 3:15 PM, Rafał Miłecki <rafal@milecki.pl> wrote:
> On 2017-02-02 01:31, Zac Schroff wrote:
>>
>> How about BCMA_IOCTL_PRESERVE_ACROSS_INIT?
>
>
> I think wireless drivers may still set some these bits during init.
>
> I've a simpler idea: make it bgmac specific. Call it sth like
> BGMAC_BCMA_IOCTL_PRESERVE
> BGMAC_BCMA_IOCTL_RESERVED
> BGMAC_BCMA_IOCTL_DONT_TOUCH

Yes, I am listing out all of the fields in that register.  We can be
intelligent about what we mask off :)
diff mbox

Patch

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);
+	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
 #define BCMA_IOST			0x0500 /* IO status */
 #define  BCMA_IOST_CORE_BITS		0x0FFF
 #define  BCMA_IOST_DMA64		0x1000