Message-ID: <33ffa97c-5994-d6ac-da06-f998ee0071d8@allwinnertech.com>
Date:   Sat, 4 Feb 2023 14:05:23 +0800
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Subject: Re: [PATCH] mmc:mmc-cqhci:support interrupt coalescing
Content-Language: en-US
To:     Adrian Hunter <adrian.hunter@intel.com>, riteshh@codeaurora.org,
        asutoshd@codeaurora.org, ulf.hansson@linaro.org,
        chaotian.jing@mediatek.com, matthias.bgg@gmail.com,
        kdasu.kdev@gmail.com, alcooperx@gmail.com, f.fainelli@gmail.com,
        haibo.chen@nxp.com, shawnguo@kernel.org, agross@kernel.org,
        andersson@kernel.org, michal.simek@xilinx.com,
        thierry.reding@gmail.com, jonathanh@nvidia.com
Cc:     bcm-kernel-feedback-list@broadcom.com, kernel@pengutronix.de,
        festevam@gmail.com, linux-imx@nxp.com, konrad.dybcio@linaro.org,
        linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-arm-msm@vger.kernel.org,
        linux-tegra@vger.kernel.org
References: <20230130064656.106793-1-michael@allwinnertech.com>
 <2463a92b-c180-87d4-0c96-2f549a397164@intel.com>
 <610b5f73-f9e3-deb2-2754-e8939ed00ec3@allwinnertech.com>
 <28d3348d-82ec-988f-718a-2d73bce585f3@intel.com>
From:   Michael Wu <michael@allwinnertech.com>
In-Reply-To: <28d3348d-82ec-988f-718a-2d73bce585f3@intel.com>
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Precedence: bulk

Dear Adrian,

On 2023/1/31 21:32, Adrian Hunter wrote:
> On 31/01/23 15:12, Michael Wu wrote:
>> Dear Adrian，
>>
>> On 2023/1/30 23:59, Adrian Hunter wrote:
>>> On 30/01/23 08:46, Michael Wu wrote:
>>>> Support interrupt coalescing to reduce the frequency of mmc interrupts
>>>
>>> There doesn't seem to be any users.  The new parameter to
>>> cqhci_init() is always false.  New features are not usually
>>> accepted without users.
>>
>> At present, I have only supported this feature on the Allwinner platform because I have not get enough information about other vendors.
>>>
>>> There needs to be an explanation of why the change is being made.
>>
>> I consider reducing the number of interrupt context switches. Can you tell me why the community does not support this feature? I wonder whether I'm doing is correct. If it's correct, i will improve this patch and incorporate it
> 
> AFAIK the community has not made any comment on supporting interrupt coalescing for CQHCI, one way or another.
> However, it is generally expected that new features will only be added if they demonstrate some benefit.
> Just assuming that there is a benefit is not enough.
> 

Okay,  I'll provide the performance data soon.

>>>
>>> Also there doesn't seem to be any configuration of the CQIC
>>> register.
>>
>> At present, I am working on the hook function .cqe_enable that the ICCTH of CQIC is set in enable
>>>
>>>>
>>>> Signed-off-by: Michael Wu <michael@allwinnertech.com>
>>>> ---
>>>>    drivers/mmc/host/cqhci-core.c      | 20 +++++++++++++++-----
>>>>    drivers/mmc/host/cqhci.h           |  5 ++++-
>>>>    drivers/mmc/host/mtk-sd.c          |  2 +-
>>>>    drivers/mmc/host/sdhci-brcmstb.c   |  2 +-
>>>>    drivers/mmc/host/sdhci-esdhc-imx.c |  2 +-
>>>>    drivers/mmc/host/sdhci-msm.c       |  2 +-
>>>>    drivers/mmc/host/sdhci-of-arasan.c |  2 +-
>>>>    drivers/mmc/host/sdhci-pci-core.c  |  2 +-
>>>>    drivers/mmc/host/sdhci-pci-gli.c   |  2 +-
>>>>    drivers/mmc/host/sdhci-tegra.c     |  2 +-
>>>>    drivers/mmc/host/sdhci_am654.c     |  2 +-
>>>>    11 files changed, 28 insertions(+), 15 deletions(-)
>>>>
>>>> diff --git a/drivers/mmc/host/cqhci-core.c b/drivers/mmc/host/cqhci-core.c
>>>> index b3d7d6d8d654..f9cdf9f04bfc 100644
>>>> --- a/drivers/mmc/host/cqhci-core.c
>>>> +++ b/drivers/mmc/host/cqhci-core.c
>>>> @@ -420,7 +420,7 @@ static void cqhci_disable(struct mmc_host *mmc)
>>>>    }
>>>>      static void cqhci_prep_task_desc(struct mmc_request *mrq,
>>>> -                 struct cqhci_host *cq_host, int tag)
>>>> +                 struct cqhci_host *cq_host, int tag, int intr)
>>>>    {
>>>>        __le64 *task_desc = (__le64 __force *)get_desc(cq_host, tag);
>>>>        u32 req_flags = mrq->data->flags;
>>>> @@ -428,7 +428,7 @@ static void cqhci_prep_task_desc(struct mmc_request *mrq,
>>>>          desc0 = CQHCI_VALID(1) |
>>>>            CQHCI_END(1) |
>>>> -        CQHCI_INT(1) |
>>>> +        CQHCI_INT(intr) |
>>>>            CQHCI_ACT(0x5) |
>>>>            CQHCI_FORCED_PROG(!!(req_flags & MMC_DATA_FORCED_PRG)) |
>>>>            CQHCI_DATA_TAG(!!(req_flags & MMC_DATA_DAT_TAG)) |
>>>> @@ -621,7 +621,7 @@ static int cqhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
>>>>        }
>>>>          if (mrq->data) {
>>>> -        cqhci_prep_task_desc(mrq, cq_host, tag);
>>>> +        cqhci_prep_task_desc(mrq, cq_host, tag, (cq_host->intr_clsc ? 0 : 1));
>>>>              err = cqhci_prep_tran_desc(mrq, cq_host, tag);
>>>>            if (err) {
>>>> @@ -812,7 +812,7 @@ static void cqhci_finish_mrq(struct mmc_host *mmc, unsigned int tag)
>>>>    irqreturn_t cqhci_irq(struct mmc_host *mmc, u32 intmask, int cmd_error,
>>>>                  int data_error)
>>>>    {
>>>> -    u32 status;
>>>> +    u32 status, rval;
>>>>        unsigned long tag = 0, comp_status;
>>>>        struct cqhci_host *cq_host = mmc->cqe_private;
>>>>    @@ -856,6 +856,15 @@ irqreturn_t cqhci_irq(struct mmc_host *mmc, u32 intmask, int cmd_error,
>>>>            spin_unlock(&cq_host->lock);
>>>>        }
>>>>    +    if (cq_host->intr_clsc) {
>>>> +        rval = cqhci_readl(cq_host, CQHCI_IC);
>>>> +        rval |= CQHCI_IC_RESET;
>>>> +        cqhci_writel(cq_host, rval, CQHCI_IC);
>>>> +        rval = cqhci_readl(cq_host, CQHCI_IC);
>>>> +        rval &= (~CQHCI_IC_RESET);
>>>> +        cqhci_writel(cq_host, rval, CQHCI_IC);
>>>> +    }
>>>> +
>>>>        if (status & CQHCI_IS_TCL)
>>>>            wake_up(&cq_host->wait_queue);
>>>>    @@ -1172,11 +1181,12 @@ static unsigned int cqhci_ver_minor(struct cqhci_host *cq_host)
>>>>    }
>>>>      int cqhci_init(struct cqhci_host *cq_host, struct mmc_host *mmc,
>>>> -          bool dma64)
>>>> +          bool dma64, bool intr_clsc)
>>>>    {
>>>>        int err;
>>>>          cq_host->dma64 = dma64;
>>>> +    cq_host->intr_clsc = intr_clsc;
>>>>        cq_host->mmc = mmc;
>>>>        cq_host->mmc->cqe_private = cq_host;
>>>>    diff --git a/drivers/mmc/host/cqhci.h b/drivers/mmc/host/cqhci.h
>>>> index ba9387ed90eb..acf90773c30a 100644
>>>> --- a/drivers/mmc/host/cqhci.h
>>>> +++ b/drivers/mmc/host/cqhci.h
>>>> @@ -227,6 +227,9 @@ struct cqhci_host {
>>>>          /* 64 bit DMA */
>>>>        bool dma64;
>>>> +
>>>> +    /* interrupt coalescing*/
>>>> +    bool intr_clsc;
>>>>        int num_slots;
>>>>        int qcnt;
>>>>    @@ -312,7 +315,7 @@ struct platform_device;
>>>>      irqreturn_t cqhci_irq(struct mmc_host *mmc, u32 intmask, int cmd_error,
>>>>                  int data_error);
>>>> -int cqhci_init(struct cqhci_host *cq_host, struct mmc_host *mmc, bool dma64);
>>>> +int cqhci_init(struct cqhci_host *cq_host, struct mmc_host *mmc, bool dma64, bool intr_clsc);
>>>>    struct cqhci_host *cqhci_pltfm_init(struct platform_device *pdev);
>>>>    int cqhci_deactivate(struct mmc_host *mmc);
>>>>    static inline int cqhci_suspend(struct mmc_host *mmc)
>>>> diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
>>>> index edade0e54a0c..2c18f954d4b8 100644
>>>> --- a/drivers/mmc/host/mtk-sd.c
>>>> +++ b/drivers/mmc/host/mtk-sd.c
>>>> @@ -2796,7 +2796,7 @@ static int msdc_drv_probe(struct platform_device *pdev)
>>>>            host->cq_host->caps |= CQHCI_TASK_DESC_SZ_128;
>>>>            host->cq_host->mmio = host->base + 0x800;
>>>>            host->cq_host->ops = &msdc_cmdq_ops;
>>>> -        ret = cqhci_init(host->cq_host, mmc, true);
>>>> +        ret = cqhci_init(host->cq_host, mmc, true, false);
>>>>            if (ret)
>>>>                goto host_free;
>>>>            mmc->max_segs = 128;
>>>> diff --git a/drivers/mmc/host/sdhci-brcmstb.c b/drivers/mmc/host/sdhci-brcmstb.c
>>>> index f2cf3d70db79..4aeaeddbbf25 100644
>>>> --- a/drivers/mmc/host/sdhci-brcmstb.c
>>>> +++ b/drivers/mmc/host/sdhci-brcmstb.c
>>>> @@ -231,7 +231,7 @@ static int sdhci_brcmstb_add_host(struct sdhci_host *host,
>>>>            cq_host->caps |= CQHCI_TASK_DESC_SZ_128;
>>>>        }
>>>>    -    ret = cqhci_init(cq_host, host->mmc, dma64);
>>>> +    ret = cqhci_init(cq_host, host->mmc, dma64, false);
>>>>        if (ret)
>>>>            goto cleanup;
>>>>    diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
>>>> index 9e73c34b6401..7aef7abe71f1 100644
>>>> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
>>>> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
>>>> @@ -1712,7 +1712,7 @@ static int sdhci_esdhc_imx_probe(struct platform_device *pdev)
>>>>            cq_host->mmio = host->ioaddr + ESDHC_CQHCI_ADDR_OFFSET;
>>>>            cq_host->ops = &esdhc_cqhci_ops;
>>>>    -        err = cqhci_init(cq_host, host->mmc, false);
>>>> +        err = cqhci_init(cq_host, host->mmc, false, false);
>>>>            if (err)
>>>>                goto disable_ahb_clk;
>>>>        }
>>>> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
>>>> index 4ac8651d0b29..b6549d1e43ec 100644
>>>> --- a/drivers/mmc/host/sdhci-msm.c
>>>> +++ b/drivers/mmc/host/sdhci-msm.c
>>>> @@ -2153,7 +2153,7 @@ static int sdhci_msm_cqe_add_host(struct sdhci_host *host,
>>>>        if (ret)
>>>>            goto cleanup;
>>>>    -    ret = cqhci_init(cq_host, host->mmc, dma64);
>>>> +    ret = cqhci_init(cq_host, host->mmc, dma64, false);
>>>>        if (ret) {
>>>>            dev_err(&pdev->dev, "%s: CQE init: failed (%d)\n",
>>>>                    mmc_hostname(host->mmc), ret);
>>>> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
>>>> index 89c431a34c43..811f8686532d 100644
>>>> --- a/drivers/mmc/host/sdhci-of-arasan.c
>>>> +++ b/drivers/mmc/host/sdhci-of-arasan.c
>>>> @@ -1610,7 +1610,7 @@ static int sdhci_arasan_add_host(struct sdhci_arasan_data *sdhci_arasan)
>>>>        if (dma64)
>>>>            cq_host->caps |= CQHCI_TASK_DESC_SZ_128;
>>>>    -    ret = cqhci_init(cq_host, host->mmc, dma64);
>>>> +    ret = cqhci_init(cq_host, host->mmc, dma64, false);
>>>>        if (ret)
>>>>            goto cleanup;
>>>>    diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
>>>> index c359f867df0a..6f6cae6355a7 100644
>>>> --- a/drivers/mmc/host/sdhci-pci-core.c
>>>> +++ b/drivers/mmc/host/sdhci-pci-core.c
>>>> @@ -964,7 +964,7 @@ static int glk_emmc_add_host(struct sdhci_pci_slot *slot)
>>>>        if (dma64)
>>>>            cq_host->caps |= CQHCI_TASK_DESC_SZ_128;
>>>>    -    ret = cqhci_init(cq_host, host->mmc, dma64);
>>>> +    ret = cqhci_init(cq_host, host->mmc, dma64, false);
>>>>        if (ret)
>>>>            goto cleanup;
>>>>    diff --git a/drivers/mmc/host/sdhci-pci-gli.c b/drivers/mmc/host/sdhci-pci-gli.c
>>>> index 633a8ee8f8c5..6917ba339aa9 100644
>>>> --- a/drivers/mmc/host/sdhci-pci-gli.c
>>>> +++ b/drivers/mmc/host/sdhci-pci-gli.c
>>>> @@ -908,7 +908,7 @@ static int gl9763e_add_host(struct sdhci_pci_slot *slot)
>>>>        if (dma64)
>>>>            cq_host->caps |= CQHCI_TASK_DESC_SZ_128;
>>>>    -    ret = cqhci_init(cq_host, host->mmc, dma64);
>>>> +    ret = cqhci_init(cq_host, host->mmc, dma64, false);
>>>>        if (ret)
>>>>            goto cleanup;
>>>>    diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
>>>> index bff084f178c9..f98a468e8f43 100644
>>>> --- a/drivers/mmc/host/sdhci-tegra.c
>>>> +++ b/drivers/mmc/host/sdhci-tegra.c
>>>> @@ -1620,7 +1620,7 @@ static int sdhci_tegra_add_host(struct sdhci_host *host)
>>>>        if (dma64)
>>>>            cq_host->caps |= CQHCI_TASK_DESC_SZ_128;
>>>>    -    ret = cqhci_init(cq_host, host->mmc, dma64);
>>>> +    ret = cqhci_init(cq_host, host->mmc, dma64, false);
>>>>        if (ret)
>>>>            goto cleanup;
>>>>    diff --git a/drivers/mmc/host/sdhci_am654.c b/drivers/mmc/host/sdhci_am654.c
>>>> index 7ef828942df3..8e7fbee70e16 100644
>>>> --- a/drivers/mmc/host/sdhci_am654.c
>>>> +++ b/drivers/mmc/host/sdhci_am654.c
>>>> @@ -568,7 +568,7 @@ static int sdhci_am654_cqe_add_host(struct sdhci_host *host)
>>>>          host->mmc->caps2 |= MMC_CAP2_CQE;
>>>>    -    return cqhci_init(cq_host, host->mmc, 1);
>>>> +    return cqhci_init(cq_host, host->mmc, 1, false);
>>>>    }
>>>>      static int sdhci_am654_get_otap_delay(struct sdhci_host *host,
>>

-- 
Regards,
Michael Wu