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Subject: Re: [PATCH v1 1/7] net: ipa: Add support for IPA v3.1 with GSI v1.0
To:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@somainline.org>, elder@kernel.org
Cc:     bjorn.andersson@linaro.org, agross@kernel.org, davem@davemloft.net,
        kuba@kernel.org, linux-arm-msm@vger.kernel.org,
        netdev@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, konrad.dybcio@somainline.org,
        marijn.suijten@somainline.org, phone-devel@vger.kernel.org
References: <20210211175015.200772-1-angelogioacchino.delregno@somainline.org>
 <20210211175015.200772-2-angelogioacchino.delregno@somainline.org>
From:   Alex Elder <elder@ieee.org>
Message-ID: <b33a7daf-e4d5-c63a-c231-b6438562229b@ieee.org>
Date:   Wed, 5 May 2021 17:42:33 -0500
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On 2/11/21 11:50 AM, AngeloGioacchino Del Regno wrote:
> In preparation for adding support for the MSM8998 SoC's IPA,
> add the necessary bits for IPA version 3.1 featuring GSI 1.0,
> found on at least MSM8998.
> 
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>

Almost everything in this patch is the same as what is
now in the upstream code.  There were minor differences,
such as using version < IPA_VERSION_4_0 rather than
version <= IPA_VERSION_3_5_1, and some comment changes.

In this patch there is one thing you had that I did not,
and I show it below.

> ---
>   drivers/net/ipa/gsi.c          |  8 ++++----
>   drivers/net/ipa/ipa_endpoint.c | 17 +++++++++--------
>   drivers/net/ipa/ipa_main.c     |  8 ++++++--
>   drivers/net/ipa/ipa_reg.h      |  3 +++
>   drivers/net/ipa/ipa_version.h  |  1 +
>   5 files changed, 23 insertions(+), 14 deletions(-)
. . .

> diff --git a/drivers/net/ipa/ipa_main.c b/drivers/net/ipa/ipa_main.c
> index 84bb8ae92725..be191993fbec 100644
> --- a/drivers/net/ipa/ipa_main.c
> +++ b/drivers/net/ipa/ipa_main.c

. . .

> @@ -404,6 +405,9 @@ static void ipa_hardware_config(struct ipa *ipa)
>   		/* Enable open global clocks (not needed for IPA v4.5) */
>   		val = GLOBAL_FMASK;
>   		val |= GLOBAL_2X_CLK_FMASK;
> +		if (version == IPA_VERSION_3_1)
> +			val |= MISC_FMASK;
> +

This block of code is conditional on:
	if (version >= IPA_VERSION_4_0 && version < IPA_VERSION_4_5)

Therefore adding the MISC_FMASK here won't ever happen.  (It's
possible the code you were working with had some different
logic.)

I do, however, see in the msm-4.4 code that IPA v3.1 enables
the CLKON_CFG CGC_OPEN_MISC bit (only), stating that it's a
workaround.  So I will update the logic and add this.

					-Alex

>   		iowrite32(val, ipa->reg_virt + IPA_REG_CLKON_CFG_OFFSET);
>   
>   		/* Disable PA mask to allow HOLB drop */

. . .