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Message-ID: <1432711590.721.127.camel@mhfsdcap03>
Date: Wed, 27 May 2015 15:26:30 +0800
From: Yong Wu <yong.wu@...iatek.com>
To: Tomasz Figa <tfiga@...gle.com>
CC: Joerg Roedel <joro@...tes.org>, Will Deacon <will.deacon@....com>,
"Rob Herring" <robh+dt@...nel.org>,
Matthias Brugger <matthias.bgg@...il.com>,
Robin Murphy <robin.murphy@....com>,
Daniel Kurtz <djkurtz@...gle.com>,
Lucas Stach <l.stach@...gutronix.de>,
Mark Rutland <mark.rutland@....com>,
Catalin Marinas <catalin.marinas@....com>,
<linux-mediatek@...ts.infradead.org>,
Sasha Hauer <kernel@...gutronix.de>,
<srv_heupstream@...iatek.com>, <devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"open list:IOMMU DRIVERS" <iommu@...ts.linux-foundation.org>,
<pebolle@...cali.nl>, <arnd@...db.de>, <mitchelh@...eaurora.org>,
<k.zhang@...iatek.com>, <youhua.li@...iatek.com>
Subject: Re: [PATCH v2 5/6] iommu/mediatek: Add mt8173 IOMMU driver
Hi Tomasz,
Thanks. please help check my comments.
The others I will change in next version.
On Mon, 2015-05-25 at 17:29 +0900, Tomasz Figa wrote:
> Hi,
>
> Please see my comments inline.
>
> On Fri, May 15, 2015 at 6:43 PM, Yong Wu <yong.wu@...iatek.com> wrote:
> [snip]
> > +
> > +struct mtk_iommu_info {
> > + void __iomem *base;
> > + int irq;
> > + struct device *dev;
> > + struct device *larbdev[MTK_IOMMU_LARB_MAX_NR];
> > + struct clk *bclk;
> > + dma_addr_t protect_base; /* protect memory base */
> > + unsigned int larb_nr; /* local arbiter number */
> > + unsigned int larb_portid_base[MTK_IOMMU_LARB_MAX_NR];
> > + /* the port id base for each local arbiter */
>
> It might not be a bad idea to convert this kind of comments into a
> proper kerneldoc comment for the whole struct. Similarly for other
> structs in the driver.
Yes. I will delete larb_portid_base if iommu-cells is 2.
>
> [snip]
>
> > +static void mtk_iommu_clear_intr(void __iomem *m4u_base)
>
> nit: Instead of pasing m4u_base here, could you pass a pointer to the
> mtk_iommu_info here and use its base field? This would be more strict,
> because currently a void pointer permits passing anything to this
> function.
>
> > +{
> > + u32 val;
> > +
> > + val = readl(m4u_base + REG_MMU_INT_CONTROL0);
> > + val |= F_INT_L2_CLR_BIT;
> > + writel(val, m4u_base + REG_MMU_INT_CONTROL0);
> > +}
> > +
> > +static void mtk_iommu_tlb_flush_all(void *cookie)
> > +{
> > + struct mtk_iommu_domain *domain = cookie;
> > + u32 val;
> > +
> > + val = F_INVLD_EN1 | F_INVLD_EN0;
> > + writel(val, domain->imuinfo->base + REG_MMU_INV_SEL);
>
> nit: Do you need this val variable?
>
> > + writel(F_ALL_INVLD, domain->imuinfo->base + REG_MMU_INVALIDATE);
> > +}
> > +
> > +static void mtk_iommu_tlb_add_flush(unsigned long iova, size_t size,
> > + bool leaf, void *cookie)
> > +{
> > + struct mtk_iommu_domain *domain = cookie;
> > + void __iomem *m4u_base = domain->imuinfo->base;
> > + unsigned int iova_start = iova, iova_end = iova + size - 1;
> > + int ret;
> > + u32 val;
> > +
> > + val = F_INVLD_EN1 | F_INVLD_EN0;
> > + writel(val, m4u_base + REG_MMU_INV_SEL);
>
> nit: Does this write need to go through this val variable?
>
> > +
> > + writel(iova_start, m4u_base + REG_MMU_INVLD_START_A);
> > + writel(iova_end, m4u_base + REG_MMU_INVLD_END_A);
> > + writel(F_MMU_INV_RANGE, m4u_base + REG_MMU_INVALIDATE);
> > +
> > + ret = readl_poll_timeout_atomic(m4u_base + REG_MMU_CPE_DONE, val,
> > + val != 0, 10, 1000000);
> > + if (ret) {
> > + dev_warn(domain->imuinfo->dev, "Invalid tlb don't done\n");
>
> Maybe "Partial TLB flush timed out, falling back to full flush\n"?
>
> > + mtk_iommu_tlb_flush_all(cookie);
> > + }
> > + writel(0, m4u_base + REG_MMU_CPE_DONE);
> > +}
> > +
> > +static void mtk_iommu_flush_pgtable(void *ptr, size_t size, void *cookie)
> > +{
> > + /*
> > + * After delete arch_setup_dma_ops,
> > + * This will be replaced with dma_map_page
> > + */
> > + __dma_flush_range(ptr, ptr + size);
> > +}
> > +
> > +static struct iommu_gather_ops mtk_iommu_gather_ops = {
> > + .tlb_flush_all = mtk_iommu_tlb_flush_all,
> > + .tlb_add_flush = mtk_iommu_tlb_add_flush,
> > + .tlb_sync = mtk_iommu_tlb_flush_all,
> > + .flush_pgtable = mtk_iommu_flush_pgtable,
> > +};
> > +
> > +static irqreturn_t mtk_iommu_isr(int irq, void *dev_id)
> > +{
> > + struct mtk_iommu_domain *mtkdomain = dev_id;
> > + struct mtk_iommu_info *piommu = mtkdomain->imuinfo;
> > + struct device *dev = piommu->dev;
> > + void __iomem *m4u_base = piommu->base;
> > + u32 int_state, regval, fault_iova, fault_pa;
> > + unsigned int fault_larb, fault_port;
> > + bool layer, write;
> > +
> > + int_state = readl(m4u_base + REG_MMU_FAULT_ST1);
> > +
> > + /* read error info from registers */
> > + fault_iova = readl(m4u_base + REG_MMU_FAULT_VA);
> > + layer = fault_iova & F_MMU_FAULT_VA_LAYER_BIT;
> > + write = fault_iova & F_MMU_FAULT_VA_WRITE_BIT;
> > + fault_iova &= F_MMU_FAULT_VA_MSK;
> > + fault_pa = readl(m4u_base + REG_MMU_INVLD_PA);
> > + regval = readl(m4u_base + REG_MMU_INT_ID);
> > + fault_larb = F_MMU0_INT_ID_LARB_ID(regval);
> > + fault_port = F_MMU0_INT_ID_PORT_ID(regval);
> > +
> > + report_iommu_fault(&mtkdomain->domain, dev, fault_iova,
> > + write ? IOMMU_FAULT_WRITE : IOMMU_FAULT_READ);
> > +
> > + if (int_state & F_INT_TRANSLATION_FAULT) {
> > + dev_err_ratelimited(
> > + dev,
> > + "fault:iova=0x%x pa=0x%x larb=%d port=%d layer=%d %s\n",
> > + fault_iova, fault_pa, fault_larb, fault_port,
> > + layer, write ? "write" : "read");
> > + }
> > +
> > + if (int_state & F_INT_MAIN_MULTI_HIT_FAULT)
> > + dev_err_ratelimited(dev,
> > + "multi-hit!iova=0x%x larb=%d port=%d\n",
> > + fault_iova, fault_larb, fault_port);
> > +
> > + if (int_state & F_INT_INVALID_PA_FAULT) {
> > + if (!(int_state & F_INT_TRANSLATION_FAULT))
> > + dev_err_ratelimited(
> > + dev,
> > + "invalid pa!iova=0x%x larb=%d port=%d\n",
> > + fault_iova, fault_larb, fault_port);
> > + }
> > + if (int_state & F_INT_ENTRY_REPLACEMENT_FAULT)
> > + dev_err_ratelimited(dev,
> > + "replace-fault!iova=0x%x larb=%d port=%d\n",
> > + fault_iova, fault_larb, fault_port);
> > +
> > + if (int_state & F_INT_TLB_MISS_FAULT)
> > + dev_err_ratelimited(dev,
> > + "tlb miss-fault!iova=0x%x larb=%d port=%d\n",
> > + fault_iova, fault_larb, fault_port);
>
> Hmm, do you need so many prints here? Could you just dump the full
> state (including int_state) regardless of interrupt type here? Also I
> wonder if this shouldn't be printed only when report_iommu_fault()
> returns -ENOSYS.
F_INT_TRANSLATION_FAULT And F_INT_INVALID_PA_FAULT is the most
common case. Can we reserve them? the others we could delete and print
int_state. About report_iommu_fault, like the other iommu, we check
return 0 if it is successful.
Then How about it if it's like this:
//===========
if(!report_iommu_fault(&mtkdomain->domain, dev, fault_iova,
write ? IOMMU_FAULT_WRITE :
IOMMU_FAULT_READ)){
goto irq_clear;
}
if (int_state & F_INT_TRANSLATION_FAULT) {
dev_err_ratelimited(
dev,
"fault:iova=0x%x pa=0x%x larb=%d port=%d layer=%d
%s\n",
fault_iova, fault_pa, fault_larb, fault_port,
layer, write ? "write" : "read");
} else if (int_state & F_INT_INVALID_PA_FAULT) {
dev_err_ratelimited(
dev,
"invalid pa!iova=0x%x larb=%d port=%d\n",
fault_iova, fault_larb, fault_port);
} else {
dev_err_ratelimited(dev,"int state 0x%x,iova=0x%x larb=%d port=%d\n",
int_state, fault_iova, fault_larb, fault_port);
}
irq_clear:
mtk_iommu_tlb_flush_all(mtkdomain);
mtk_iommu_clear_intr(m4u_base);
return IRQ_HANDLED;
//=======
>
> > +
> > + mtk_iommu_tlb_flush_all(mtkdomain);
> > +
> > + mtk_iommu_clear_intr(m4u_base);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static int mtk_iommu_parse_dt(struct platform_device *pdev,
> > + struct mtk_iommu_info *piommu)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct device_node *ofnode;
> > + struct resource *res;
> > + unsigned int i, port_nr, lastportnr = 0;
> > + int ret;
> > +
> > + ofnode = dev->of_node;
> > +
> > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > + piommu->base = devm_ioremap_resource(&pdev->dev, res);
> > + if (IS_ERR(piommu->base)) {
> > + dev_err(dev, "Failed to get base (%lx)\n",
> > + PTR_ERR(piommu->base));
>
> devm_ioremap_resource() already prints a message on error.
>
> > + ret = PTR_ERR(piommu->base);
> > + goto err_parse_dt;
>
> You can just return PTR_ERR(piommu->base) here directly.
>
> > + }
> > +
> > + piommu->irq = platform_get_irq(pdev, 0);
> > + if (piommu->irq < 0) {
> > + dev_err(dev, "Failed to get IRQ (%d)\n", piommu->irq);
> > + ret = piommu->irq;
> > + goto err_parse_dt;
>
> Again just return.
>
> > + }
> > +
> > + piommu->bclk = devm_clk_get(dev, "bclk");
> > + if (IS_ERR(piommu->bclk)) {
> > + dev_err(dev, "Failed to get the bclk (%lx)\n",
> > + PTR_ERR(piommu->bclk));
> > + ret = PTR_ERR(piommu->bclk);
> > + goto err_parse_dt;
>
> Ditto.
>
> > + }
> > +
> > + ret = of_property_count_u32_elems(ofnode, "larb-portes-nr");
>
> According to my comments to the patch adding the binding, you should
> rather count the number of phandles in "larb" property by
> of_count_phandle_with_args(ofnode, "larb", NULL).
Thanks. I will delete this.
>
> > + if (ret < 0) {
> > + dev_err(dev, "Failed to get larb-portes-nr\n");
> > + goto err_parse_dt;
>
> Ditto.
>
> > + } else {
> > + piommu->larb_nr = ret;
>
> You can take this out of "else" block.
>
> > + }
> > +
> > + for (i = 0; i < piommu->larb_nr; i++) {
> > + ret = of_property_read_u32_index(ofnode, "larb-portes-nr",
> > + i, &port_nr);
>
> For logical correctness, you should parse port count from larb node,
> as I mentioned in my comments to the patch adding the binding. However
> I'm not sure if you even need to know the number of ports. I will
> comment more on this below.
>
> > + if (ret) {
> > + dev_err(dev, "Failed to get the port nr@...b%d\n", i);
> > + goto err_parse_dt;
>
> Just return here.
>
> > + } else {
>
> > + piommu->larb_portid_base[i] = lastportnr;
> > + lastportnr += port_nr;
>
> This looks like creating an artificial 1-dimensional namespace from a
> natural 2-dimensional space indexed by (larb, port) tuple.
>
> Also you can take this out of the else block.
>
> > + }
> > + }
> > + piommu->larb_portid_base[i] = lastportnr;
> > +
> > + for (i = 0; i < piommu->larb_nr; i++) {
> > + struct device_node *larbnode;
> > + struct platform_device *plarbdev;
> > +
> > + larbnode = of_parse_phandle(ofnode, "larb", i);
> > + if (!larbnode) {
> > + dev_err(dev, "Failed to get the larb property\n");
> > + ret = -EINVAL;
> > + goto err_parse_dt;
>
> Just return.
>
> > + }
> > + plarbdev = of_find_device_by_node(larbnode);
> > + of_node_put(larbnode);
> > + if (!plarbdev) {
> > + dev_err(dev, "Failed to get the dev@...b%d\n", i);
> > + ret = -EINVAL;
> > + goto err_parse_dt;
>
> Just return.
>
> > + } else {
> > + piommu->larbdev[i] = &plarbdev->dev;
>
> Again, no need to put this into else block.
>
> > + }
> > + }
> > +
> > + return 0;
> > +
> > +err_parse_dt:
> > + return ret;
>
> Now, after addressing my comments above, this label can be removed.
>
> > +}
> > +
> > +static int mtk_iommu_hw_init(const struct mtk_iommu_domain *mtkdomain)
> > +{
> > + struct mtk_iommu_info *piommu = mtkdomain->imuinfo;
> > + void __iomem *m4u_base = piommu->base;
> > + u32 regval;
> > + int ret = 0;
> > +
> > + ret = clk_prepare_enable(piommu->bclk);
> > + if (ret)
> > + return -ENODEV;
>
> Why overriding the error returned in ret with -ENODEV?
>
> > +
> > + writel(mtkdomain->cfg.arm_short_cfg.ttbr[0],
> > + m4u_base + REG_MMU_PT_BASE_ADDR);
> > +
> > + regval = F_MMU_PREFETCH_RT_REPLACE_MOD |
> > + F_MMU_TF_PROTECT_SEL(2) |
> > + F_COHERENCE_EN;
> > + writel(regval, m4u_base + REG_MMU_CTRL_REG);
> > +
> > + regval = F_L2_MULIT_HIT_EN |
> > + F_TABLE_WALK_FAULT_INT_EN |
> > + F_PREETCH_FIFO_OVERFLOW_INT_EN |
> > + F_MISS_FIFO_OVERFLOW_INT_EN |
> > + F_PREFETCH_FIFO_ERR_INT_EN |
> > + F_MISS_FIFO_ERR_INT_EN;
> > + writel(regval, m4u_base + REG_MMU_INT_CONTROL0);
> > +
> > + regval = F_INT_TRANSLATION_FAULT |
> > + F_INT_MAIN_MULTI_HIT_FAULT |
> > + F_INT_INVALID_PA_FAULT |
> > + F_INT_ENTRY_REPLACEMENT_FAULT |
> > + F_INT_TLB_MISS_FAULT |
> > + F_INT_MISS_TRANSATION_FIFO_FAULT |
> > + F_INT_PRETETCH_TRANSATION_FIFO_FAULT;
> > + writel(regval, m4u_base + REG_MMU_INT_MAIN_CONTROL);
> > +
> > + regval = ALIGN(piommu->protect_base, MTK_PROTECT_PA_ALIGN);
> > + regval = (u32)F_MMU_IVRP_PA_SET(regval);
> > + writel(regval, m4u_base + REG_MMU_IVRP_PADDR);
> > +
> > + writel(0, m4u_base + REG_MMU_DCM_DIS);
> > + writel(0, m4u_base + REG_MMU_STANDARD_AXI_MODE);
> > +
> > + if (devm_request_irq(piommu->dev, piommu->irq, mtk_iommu_isr, 0,
> > + dev_name(piommu->dev), (void *)mtkdomain)) {
> > + dev_err(piommu->dev, "Failed @ IRQ-%d Request\n", piommu->irq);
> > + return -ENODEV;
>
> Hmm, this keeps the clock enabled. Should you add clean-up path
> uninitializing the hardware and stopping the clock?
ok. I will clk_diable and write 0 to pagetable base address register.
>
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int mtk_iommu_config_port(struct mtk_iommu_info *piommu,
> > + int portid, bool iommuen)
> > +{
> > + bool validlarb = false;
> > + int i, larbid, larbportid;
> > + int ret;
> > +
> > + if (portid >= piommu->larb_portid_base[piommu->larb_nr]) {
> > + dev_err(piommu->dev, "Invalid portid (%d)\n", portid);
> > + return -EINVAL;
> > + }
> > +
> > + for (i = piommu->larb_nr - 1; i >= 0; i--) {
> > + if (portid >= piommu->larb_portid_base[i]) {
> > + larbid = i;
> > + larbportid = portid -
> > + piommu->larb_portid_base[i];
> > + validlarb = true;
> > + break;
> > + }
> > + }
>
> There would be no need for this magic here if two cells was used for
> port specifier in DT. By the way, this function seems to be the only
> user of port count, so if you don't strictly need the check for port
> specifier being in range, then such information could be simply
> removed from DT, simplifying the binding.
Thanks. I will follow it.
>
> > +
> > + if (validlarb) {
> > + ret = mtk_smi_config_port(piommu->larbdev[larbid],
> > + larbportid, iommuen);
> > + if (ret) {
> > + dev_err(piommu->dev,
> > + "Failed to config port portid-%d\n", portid);
> > + }
> > + } else {
> > + ret = -EINVAL;
> > + dev_err(piommu->dev, "Failed to find out portid-%d\n", portid);
> > + }
> > + return ret;
> > +}
> > +
> > +static int mtk_iommu_dev_enable_iommu(struct mtk_iommu_info *imuinfo,
> > + struct device *dev, bool enable)
> > +{
> > + struct of_phandle_args out_args = {0};
> > + struct device *imudev = imuinfo->dev;
> > + unsigned int i = 0;
> > + int ret = 0;
> > +
> > + while (!of_parse_phandle_with_args(dev->of_node, "iommus",
> > + "#iommu-cells", i++, &out_args)) {
> > + if (out_args.np != imudev->of_node)
> > + continue;
> > + if (out_args.args_count != 1) {
> > + dev_err(imudev,
> > + "invalid #iommu-cells property for IOMMU\n");
> > + }
>
> I don't believe you need to do this manually. I can see
> of_iommu_configure() in
> http://lxr.free-electrons.com/source/drivers/iommu/of_iommu.c#L136 ,
> which I believe should call .of_xlate from your iommu_ops with correct
> node and verified the args count. This callback should parse the args
> and prepare some private data.
>
> I don't see any example of such .of_xlate callback though. Could
> someone (Joerg, Will?) advise how this could be used and in particular
> how the data obtained from parsing the args should be stored for
> further use?
I have test of_xlate. It could help parse the args.
In arm64 dma v2 of Robin, We can not get the standard "iommu_dma_ops" in
dma_mapping.c except calling arch_setup_dma_ops, It is static.
So I don't change it here in this version.
and We may get the dma v3 this weekend.
So in next version, we will try to use of_xlate to replace this.
>
> > +
> > + dev_dbg(imudev, "%s iommu @ port:%d\n",
> > + enable ? "enable" : "disable", out_args.args[0]);
> > +
> > + ret = mtk_iommu_config_port(imuinfo, out_args.args[0], enable);
> > + if (!ret)
> > + dev->archdata.dma_ops = (enable) ?
> > + imudev->archdata.dma_ops : NULL;
> > + else
> > + break;
> > + }
> > + return ret;
> > +}
> > +
> > +static struct iommu_domain *mtk_iommu_domain_alloc(unsigned type)
> > +{
> > + struct mtk_iommu_domain *priv;
> > +
> > + /* We only support unmanaged domains for now */
> > + if (type != IOMMU_DOMAIN_UNMANAGED)
> > + return NULL;
> > +
> > + priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> > + if (!priv)
> > + return ERR_PTR(-ENOMEM);
>
> What's the proper return convention of this function? The first error
> case returns NULL, while this an error pointer. One of them is most
> likely wrong.
I will change to return NULL both.
>
> > +
> > + priv->cfg.quirks = IO_PGTABLE_QUIRK_ARM_NS;
> > + priv->cfg.pgsize_bitmap = SZ_16M | SZ_1M | SZ_64K | SZ_4K,
> > + priv->cfg.ias = 32;
> > + priv->cfg.oas = 32;
> > + priv->cfg.tlb = &mtk_iommu_gather_ops;
> > +
> > + priv->iop = alloc_io_pgtable_ops(ARM_SHORT_DESC, &priv->cfg, priv);
> > + if (!priv->iop) {
> > + pr_err("Failed to alloc io pgtable@MTK iommu\n");
> > + goto err_free_priv;
> > + }
> > +
> > + spin_lock_init(&priv->pgtlock);
> > +
> > + priv->domain.geometry.aperture_start = 0;
> > + priv->domain.geometry.aperture_end = ~0;
>
> Should this be UL or ULL?
>
> > + priv->domain.geometry.force_aperture = true;
> > +
> > + return &priv->domain;
> > +
> > +err_free_priv:
> > + kfree(priv);
> > + return NULL;
> > +}
> > +
> > +static void mtk_iommu_domain_free(struct iommu_domain *domain)
> > +{
> > + struct mtk_iommu_domain *priv = to_mtk_domain(domain);
> > +
> > + free_io_pgtable_ops(priv->iop);
> > + kfree(priv);
> > +}
> > +
> > +static int mtk_iommu_attach_device(struct iommu_domain *domain,
> > + struct device *dev)
> > +{
> > + struct mtk_iommu_domain *priv = to_mtk_domain(domain);
> > + int ret;
> > +
> > + /* word around for arch_setup_dma_ops */
>
> typo: s/word around/Workaround/
>
> Anyway, could you remind me what was the issue with arch_setup_dma_ops, please?
As above.
>
> > + if (!priv->imuinfo)
> > + ret = 0;
> > + else
> > + ret = mtk_iommu_dev_enable_iommu(priv->imuinfo, dev, true);
> > + return ret;
>
> Maybe you could rewrite the 5 lines above into the following:
>
> if (!priv->imuinfo)
> return 0;
> return mtk_iommu_dev_enable_iommu(priv->imuinfo, dev, true);
>
> > +}
> > +
[snip]
> > +static int mtk_iommu_probe(struct platform_device *pdev)
> > +{
> > + struct iommu_domain *domain;
> > + struct mtk_iommu_domain *mtk_domain;
> > + struct mtk_iommu_info *piommu;
> > + void __iomem *protect;
> > + int ret;
>
> CodingStyle: Please no tabs in local variable declarations.
>
> > +
> > + piommu = devm_kzalloc(&pdev->dev, sizeof(*piommu), GFP_KERNEL);
> > + if (!piommu)
> > + return -ENOMEM;
> > +
> > + piommu->dev = &pdev->dev;
> > +
> > + /*
> > + * Alloc for Protect memory.
> > + * HW will access here while translation fault.
> > + */
> > + protect = devm_kzalloc(piommu->dev, MTK_PROTECT_PA_ALIGN * 2,
> > + GFP_KERNEL);
> > + if (!protect)
> > + return -ENOMEM;
> > + piommu->protect_base = dma_map_single(piommu->dev, protect,
> > + MTK_PROTECT_PA_ALIGN * 2,
> > + DMA_TO_DEVICE); /* clean cache */
> > +
> > + ret = mtk_iommu_parse_dt(pdev, piommu);
> > + if (ret)
> > + return ret;
>
> What about the potential dma mapping created by dma_map_single()? (I'm
> not sure how important is to clean this up in practice, but for
> consistency, it should be handled in error path to prevent leaking
> memory if something changes in future in DMA API internals.)
I think it maybe not important if we don't clean cache.That is to say
that we can delete this dma_map_single.
If the protect memory don't do cache sync, HW may read some random data
while translation fault, Then the multimedia HW output may random
error, It maybe don't need to care.
At that time, iommu will print translation fault log. I think the
multimedia module owner should resolve the translation fault issue
firstly.
And There is no error path. HW will access protect memory while
translation fault. This is HW behavior. If we disable this protect
function, HW will access what it read.the fault address maybe random.
It will be more dangerous.
>
> > +
> > + /*
> > + * arch_setup_dma_ops is not proper.
> > + * It should be replaced it with iommu_dma_create_domain
> > + * in next dma patch.
> > + */
> > + arch_setup_dma_ops(piommu->dev, 0, (1ULL << 32) - 1, &mtk_iommu_ops, 0);
> > +
> > + domain = iommu_dma_raw_domain(get_dma_domain(piommu->dev));
> > + if (!domain) {
> > + dev_err(piommu->dev, "Failed to get iommu domain\n");
> > + ret = -EINVAL;
> > + goto err_free_domain;
> > + }
> > +
> > + mtk_domain = to_mtk_domain(domain);
> > + mtk_domain->imuinfo = piommu;
> > +
> > + dev_set_drvdata(piommu->dev, piommu);
> > +
> > + ret = mtk_iommu_hw_init(mtk_domain);
> > + if (ret < 0) {
> > + dev_err(piommu->dev, "Failed @ HW init\n");
>
> nit: Maybe "Hardware initialization failed"?
>
> > + goto err_free_domain;
> > + }
> > +
> > + return 0;
> > +
> > +err_free_domain:
> > + arch_teardown_dma_ops(piommu->dev);
>
> Shouldn't the label be called err_teardown_dma_ops then?
>
> Best regards,
> Tomasz
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