Re: [PATCH 2/5] iommu/mediatek: Add mt8173 IOMMU driver

From: Mitchel Humpherys <mitchelh@codeaurora.org>
To: Yong Wu <yong.wu@mediatek.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	devicetree@vger.kernel.org, srv_heupstream@mediatek.com,
	Catalin Marinas <catalin.marinas@arm.com>,
	Joerg Roedel <joro@8bytes.org>, Will Deacon <will.deacon@arm.com>,
	linux-kernel@vger.kernel.org, Tomasz Figa <tfiga@google.com>,
	iommu@lists.linux-foundation.org,
	Rob Herring <robh+dt@kernel.org>,
	Daniel Kurtz <djkurtz@google.com>,
	Sasha Hauer <kernel@pengutronix.de>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	linux-mediatek@lists.infradead.org,
	Robin Murphy <robin.murphy@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	Lucas Stach <l.stach@pengutronix.de>
Subject: Re: [PATCH 2/5] iommu/mediatek: Add mt8173 IOMMU driver
Date: Mon, 09 Mar 2015 09:57:45 -0700	[thread overview]
Message-ID: <vnkwwq2qrtva.fsf@mitchelh-linux.qualcomm.com> (raw)
In-Reply-To: <1425903386.13300.33.camel@mhfsdcap03> (Yong Wu's message of "Mon, 9 Mar 2015 20:16:26 +0800")

On Mon, Mar 09 2015 at 05:16:26 AM, Yong Wu <yong.wu@mediatek.com> wrote:
> Dear Mitchel,
>      Thanks very much for your review.
>
> On Fri, 2015-03-06 at 09:15 -0800, Mitchel Humpherys wrote:
>> On Fri, Mar 06 2015 at 02:48:17 AM, <yong.wu@mediatek.com> wrote:
>> > From: Yong Wu <yong.wu@mediatek.com>
>> >
>> > This patch adds support for mediatek m4u (MultiMedia Memory Management Unit).
>> > Currently this only supports m4u gen 2 with 2 levels of page table on mt8173.
>> 
>> [...]
>> 
>> > +static int mtk_iommu_invalidate_tlb(const struct mtk_iommu_info *piommu,
>> > +				    int isinvall, unsigned int iova_start,
>> > +				    unsigned int iova_end)
>> > +{
>> > +	void __iomem *m4u_base = piommu->m4u_base;
>> > +	u32 val;
>> > +	u64 start, end;
>> > +
>> > +	start = sched_clock();
>> > +
>> > +	if (!isinvall) {
>> > +		iova_start = round_down(iova_start, SZ_4K);
>> > +		iova_end = round_up(iova_end, SZ_4K);
>> > +	}
>> > +
>> > +	val = F_MMU_INV_EN_L2 | F_MMU_INV_EN_L1;
>> > +
>> > +	writel(val, m4u_base + REG_INVLID_SEL);
>> > +
>> > +	if (isinvall) {
>> > +		writel(F_MMU_INV_ALL, m4u_base + REG_MMU_INVLD);
>> > +	} else {
>> > +		writel(iova_start, m4u_base + REG_MMU_INVLD_SA);
>> > +		writel(iova_end, m4u_base + REG_MMU_INVLD_EA);
>> > +		writel(F_MMU_INV_RANGE, m4u_base + REG_MMU_INVLD);
>> > +
>> > +		while (!readl(m4u_base + REG_MMU_CPE_DONE)) {
>> > +			end = sched_clock();
>> > +			if (end - start >= 100000000ULL) {
>> > +				dev_warn(piommu->dev, "invalid don't done\n");
>> > +				writel(F_MMU_INV_ALL, m4u_base + REG_MMU_INVLD);
>> > +			}
>> > +		};
>> 
>> Superfluous `;'.  Also, maybe you should be using readl_poll_timeout?
>    Thanks.
>    For the "readl_poll_timeout", My base is 3.19-rc7 and robin's patch.
> it don't have this interface.  I will try to add it in the next version.

Yeah it was merged in v4.0-rc1.

-Mitch

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