[PATCH v2 1/1] ipmi: NPCM7xx KCS BMC: enable interrupt to the host

[Avi Fishman]

On Wed, May 23, 2018 at 3:05 PM, Corey Minyard <minyard at acm.org> wrote:
> On 05/23/2018 04:40 AM, Avi Fishman wrote:
>>
>> On Tue, May 22, 2018 at 9:52 PM, Corey Minyard <minyard at acm.org> wrote:
>>>
>>> On 05/21/2018 07:39 AM, avifishman70 at gmail.com wrote:
>>>>
>>>> From: Avi Fishman <AviFishman70 at gmail.com>
>>>>
>>>> Original kcs_bmc_npcm7xx.c was missing enabling to send interrupt to the
>>>> host on writes to output buffer.
>>>> This patch fixes it by setting the bits that enables the generation of
>>>> IRQn events by hardware control based on the status of the OBF flag.
>>>
>>>
>>> This look ok, I've added it to my 4.19 queue.
>>
>> Thanks Corey,
>>
>> Since drivers/char/ipmi/kcs_bmc_npcm7xx.c already exists in linux-next
>> (4.18) what not adding it as a fix in 4.18?
>
>
> I try not to add new stuff at this stage in the game.  I was debating
> whether this is a bugfix or a new feature.  If you have a pressing need to
> have it in 4.18, I can consider that.
>
> -corey

Without this fix the host is doing polling at a very slow rate, when
the host is triggered by an interrupt the response is much more
faster.
Note that the same people who tested and approved the original driver
reported the performance issue and they tested it with this fix and
also approved.
They and I will appriciate if it will be in 4.18 :)

-Avi

>
>
>> -Avi
>>
>>> -corey
>>>
>>>
>>>> Signed-off-by: Avi Fishman <AviFishman70 at gmail.com>
>>>> Reviewed-by:   Haiyue Wang <haiyue.wang at linux.intel.com>
>>>> ---
>>>>    drivers/char/ipmi/kcs_bmc_npcm7xx.c | 17 ++++++++++++++---
>>>>    1 file changed, 14 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/char/ipmi/kcs_bmc_npcm7xx.c
>>>> b/drivers/char/ipmi/kcs_bmc_npcm7xx.c
>>>> index 7bc898c5d372..722f7391fe1f 100644
>>>> --- a/drivers/char/ipmi/kcs_bmc_npcm7xx.c
>>>> +++ b/drivers/char/ipmi/kcs_bmc_npcm7xx.c
>>>> @@ -39,6 +39,12 @@
>>>>    #define KCS3CTL               0x3C
>>>>    #define    KCS_CTL_IBFIE      BIT(0)
>>>>    +#define KCS1IE               0x1C
>>>> +#define KCS2IE         0x2E
>>>> +#define KCS3IE         0x40
>>>> +#define    KCS_IE_IRQE          BIT(0)
>>>> +#define    KCS_IE_HIRQE         BIT(3)
>>>> +
>>>>    /*
>>>>     * 7.2.4 Core KCS Registers
>>>>     * Registers in this module are 8 bits. An 8-bit register must be
>>>> accessed
>>>> @@ -48,12 +54,14 @@
>>>>     * dob: KCS Channel n Data Out Buffer Register (KCSnDO).
>>>>     * dib: KCS Channel n Data In Buffer Register (KCSnDI).
>>>>     * ctl: KCS Channel n Control Register (KCSnCTL).
>>>> + * ie : KCS Channel n  Interrupt Enable Register (KCSnIE).
>>>>     */
>>>>    struct npcm7xx_kcs_reg {
>>>>          u32 sts;
>>>>          u32 dob;
>>>>          u32 dib;
>>>>          u32 ctl;
>>>> +       u32 ie;
>>>>    };
>>>>      struct npcm7xx_kcs_bmc {
>>>> @@ -63,9 +71,9 @@ struct npcm7xx_kcs_bmc {
>>>>    };
>>>>      static const struct npcm7xx_kcs_reg
>>>> npcm7xx_kcs_reg_tbl[KCS_CHANNEL_MAX] = {
>>>> -       { .sts = KCS1ST, .dob = KCS1DO, .dib = KCS1DI, .ctl = KCS1CTL },
>>>> -       { .sts = KCS2ST, .dob = KCS2DO, .dib = KCS2DI, .ctl = KCS2CTL },
>>>> -       { .sts = KCS3ST, .dob = KCS3DO, .dib = KCS3DI, .ctl = KCS3CTL },
>>>> +       { .sts = KCS1ST, .dob = KCS1DO, .dib = KCS1DI, .ctl = KCS1CTL,
>>>> .ie
>>>> = KCS1IE },
>>>> +       { .sts = KCS2ST, .dob = KCS2DO, .dib = KCS2DI, .ctl = KCS2CTL,
>>>> .ie
>>>> = KCS2IE },
>>>> +       { .sts = KCS3ST, .dob = KCS3DO, .dib = KCS3DI, .ctl = KCS3CTL,
>>>> .ie
>>>> = KCS3IE },
>>>>    };
>>>>      static u8 npcm7xx_kcs_inb(struct kcs_bmc *kcs_bmc, u32 reg)
>>>> @@ -95,6 +103,9 @@ static void npcm7xx_kcs_enable_channel(struct kcs_bmc
>>>> *kcs_bmc, bool enable)
>>>>          regmap_update_bits(priv->map, priv->reg->ctl, KCS_CTL_IBFIE,
>>>>                             enable ? KCS_CTL_IBFIE : 0);
>>>> +
>>>> +       regmap_update_bits(priv->map, priv->reg->ie, KCS_IE_IRQE |
>>>> KCS_IE_HIRQE,
>>>> +                          enable ? KCS_IE_IRQE | KCS_IE_HIRQE : 0);
>>>>    }
>>>>      static irqreturn_t npcm7xx_kcs_irq(int irq, void *arg)
>>>
>>>
>>>
>