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From: Yong Wu <yong.wu@mediatek.com>
To: Matthias Brugger <matthias.bgg@gmail.com>
Cc: youlin.pei@mediatek.com, devicetree@vger.kernel.org,
	Nicolas Boichat <drinkcat@chromium.org>,
	srv_heupstream@mediatek.com, Joerg Roedel <joro@8bytes.org>,
	Will Deacon <will.deacon@arm.com>,
	linux-kernel@vger.kernel.org, Evan Green <evgreen@chromium.org>,
	Tomasz Figa <tfiga@google.com>,
	iommu@lists.linux-foundation.org,
	Rob Herring <robh+dt@kernel.org>,
	linux-mediatek@lists.infradead.org, yingjoe.chen@mediatek.com,
	anan.sun@mediatek.com, Robin Murphy <robin.murphy@arm.com>,
	Matthias Kaehlcke <mka@chromium.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v7 19/21] iommu/mediatek: Rename enable_4GB to dram_is_4gb
Date: Thu, 20 Jun 2019 21:59:52 +0800
Message-ID: <1561039192.4021.23.camel@mhfsdcap03> (raw)
In-Reply-To: <9bf13c22-0c73-2950-2204-23d577976b03@gmail.com>

On Tue, 2019-06-18 at 18:06 +0200, Matthias Brugger wrote:
> 
> On 10/06/2019 14:17, Yong Wu wrote:
> > This patch only rename the variable name from enable_4GB to
> > dram_is_4gb for readable.
> 
> From my understanding this is true when available RAM > 4GB so I think the name
> should be something like dram_bigger_4gb otherwise it may create confusion again.

Strictly, It is not "dram_bigger_4gb". actually if the dram size is over
3GB (the first 1GB is the register space), the "4GB mode" will be
enabled. then how about the name "dram_enable_32bit"?(the PA 32bit will
be enabled in the 4GB mode.)
     
There is another option, please see the last part in [1] suggested by
Evan, something like below:
----
data->enable_4GB = !!(max_pfn > (BIT_ULL(32) >> PAGE_SHIFT));
if (!data->plat_data->has_4gb_mode)
    data->enable_4GB = false;
Then mtk_iommu_map would only have:
    if (data->enable_4GB)
         paddr |= BIT_ULL(32);
----

Which one do you prefer?      
      
[1] https://lore.kernel.org/patchwork/patch/1028421/

> 
> Also from my point of view this patch should be done before
> "[PATCH 06/21] iommu/io-pgtable-arm-v7s: Extend MediaTek 4GB Mode"

OK.

> 
> Regards,
> Matthias
> 
> > 
> > Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> > Reviewed-by: Evan Green <evgreen@chromium.org>
> > ---
> >  drivers/iommu/mtk_iommu.c | 10 +++++-----
> >  drivers/iommu/mtk_iommu.h |  2 +-
> >  2 files changed, 6 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 86158d8..67cab2d 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -382,7 +382,7 @@ static int mtk_iommu_map(struct iommu_domain *domain, unsigned long iova,
> >  	int ret;
> >  
> >  	/* The "4GB mode" M4U physically can not use the lower remap of Dram. */
> > -	if (data->plat_data->has_4gb_mode && data->enable_4GB)
> > +	if (data->plat_data->has_4gb_mode && data->dram_is_4gb)
> >  		paddr |= BIT_ULL(32);
> >  
> >  	spin_lock_irqsave(&dom->pgtlock, flags);
> > @@ -554,13 +554,13 @@ static int mtk_iommu_hw_init(const struct mtk_iommu_data *data)
> >  	writel_relaxed(regval, data->base + REG_MMU_INT_MAIN_CONTROL);
> >  
> >  	if (data->plat_data->m4u_plat == M4U_MT8173)
> > -		regval = (data->protect_base >> 1) | (data->enable_4GB << 31);
> > +		regval = (data->protect_base >> 1) | (data->dram_is_4gb << 31);
> >  	else
> >  		regval = lower_32_bits(data->protect_base) |
> >  			 upper_32_bits(data->protect_base);
> >  	writel_relaxed(regval, data->base + REG_MMU_IVRP_PADDR);
> >  
> > -	if (data->enable_4GB && data->plat_data->has_vld_pa_rng) {
> > +	if (data->dram_is_4gb && data->plat_data->has_vld_pa_rng) {
> >  		/*
> >  		 * If 4GB mode is enabled, the validate PA range is from
> >  		 * 0x1_0000_0000 to 0x1_ffff_ffff. here record bit[32:30].
> > @@ -611,8 +611,8 @@ static int mtk_iommu_probe(struct platform_device *pdev)
> >  		return -ENOMEM;
> >  	data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN);
> >  
> > -	/* Whether the current dram is over 4GB */
> > -	data->enable_4GB = !!(max_pfn > (BIT_ULL(32) >> PAGE_SHIFT));
> > +	/* Whether the current dram is 4GB. */
> > +	data->dram_is_4gb = !!(max_pfn > (BIT_ULL(32) >> PAGE_SHIFT));
> >  
> >  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >  	data->base = devm_ioremap_resource(dev, res);
> > diff --git a/drivers/iommu/mtk_iommu.h b/drivers/iommu/mtk_iommu.h
> > index 753266b..e8114b2 100644
> > --- a/drivers/iommu/mtk_iommu.h
> > +++ b/drivers/iommu/mtk_iommu.h
> > @@ -65,7 +65,7 @@ struct mtk_iommu_data {
> >  	struct mtk_iommu_domain		*m4u_dom;
> >  	struct iommu_group		*m4u_group;
> >  	struct mtk_smi_iommu		smi_imu;      /* SMI larb iommu info */
> > -	bool                            enable_4GB;
> > +	bool                            dram_is_4gb;
> >  	bool				tlb_flush_active;
> >  
> >  	struct iommu_device		iommu;
> > 



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Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-10 12:17 [PATCH v7 00/21] MT8183 IOMMU SUPPORT Yong Wu
2019-06-10 12:17 ` [PATCH v7 01/21] dt-bindings: mediatek: Add binding for mt8183 IOMMU and SMI Yong Wu
2019-06-10 12:17 ` [PATCH v7 02/21] iommu/mediatek: Use a struct as the platform data Yong Wu
2019-06-10 12:17 ` [PATCH v7 03/21] memory: mtk-smi: Use a general config_port interface Yong Wu
2019-06-10 12:17 ` [PATCH v7 04/21] memory: mtk-smi: Use a struct for the platform data for smi-common Yong Wu
2019-06-10 12:17 ` [PATCH v7 05/21] iommu/io-pgtable-arm-v7s: Add paddr_to_iopte and iopte_to_paddr helpers Yong Wu
2019-06-10 12:17 ` [PATCH v7 06/21] iommu/io-pgtable-arm-v7s: Extend MediaTek 4GB Mode Yong Wu
2019-06-10 12:17 ` [PATCH v7 07/21] iommu/mediatek: Add bclk can be supported optionally Yong Wu
2019-06-15 19:18   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 08/21] iommu/mediatek: Add larb-id remapped support Yong Wu
2019-06-17  9:25   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 09/21] iommu/mediatek: Refine protect memory definition Yong Wu
2019-06-17  9:59   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 10/21] iommu/mediatek: Move reset_axi into plat_data Yong Wu
2019-06-17 10:19   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 11/21] iommu/mediatek: Move vld_pa_rng " Yong Wu
2019-06-17 10:27   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 12/21] memory: mtk-smi: Add gals support Yong Wu
2019-06-17 15:43   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 13/21] iommu/mediatek: Add mt8183 IOMMU support Yong Wu
2019-06-17 15:51   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 14/21] iommu/mediatek: Add mmu1 support Yong Wu
2019-06-17 15:58   ` Matthias Brugger
2019-06-18  6:19   ` Tomasz Figa
2019-06-18 12:09     ` Yong Wu
2019-06-18 14:05       ` Tomasz Figa
2019-06-10 12:17 ` [PATCH v7 15/21] memory: mtk-smi: Invoke pm runtime_callback to enable clocks Yong Wu
2019-06-17 16:13   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 16/21] memory: mtk-smi: Add bus_sel for mt8183 Yong Wu
2019-06-13  8:20   ` Pi-Hsun Shih
2019-06-17 16:28     ` Matthias Brugger
2019-06-17 16:23   ` Matthias Brugger
2019-06-18 12:10     ` Yong Wu
2019-06-18 21:07       ` Matthias Brugger
     [not found]   ` <CANdKZ0d873PJ2u=Hn_aUJBu3dDiNyueVwBv94-VXHGLJBvAbGg@mail.gmail.com>
2019-06-20  9:35     ` Matthias Brugger
2019-06-20 11:38       ` Matthias Brugger
2019-06-21  3:57         ` Pi-Hsun Shih
2019-06-10 12:17 ` [PATCH v7 17/21] memory: mtk-smi: Get rid of need_larbid Yong Wu
2019-06-18 13:45   ` Matthias Brugger
2019-06-20 13:59     ` Yong Wu
2019-06-10 12:17 ` [PATCH v7 18/21] iommu/mediatek: Fix VLD_PA_RNG register backup when suspend Yong Wu
2019-06-17 16:30   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 19/21] iommu/mediatek: Rename enable_4GB to dram_is_4gb Yong Wu
2019-06-18 16:06   ` Matthias Brugger
2019-06-20 13:59     ` Yong Wu [this message]
2019-06-21 10:10       ` Matthias Brugger
2019-06-22  2:42         ` Yong Wu
2019-06-10 12:17 ` [PATCH v7 20/21] iommu/mediatek: Fix iova_to_phys PA start for 4GB mode Yong Wu
2019-06-18 16:35   ` Matthias Brugger
2019-06-20 14:00     ` Yong Wu
2019-06-10 12:18 ` [PATCH v7 21/21] iommu/mediatek: Switch to SPDX license identifier Yong Wu
2019-06-17 16:33   ` Matthias Brugger

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