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Message-ID: <1592884977.14160.1.camel@mtkswgap22>
Date: Tue, 23 Jun 2020 12:02:57 +0800
From: Neal Liu <neal.liu@...iatek.com>
To: Chun-Kuang Hu <chunkuang.hu@...nel.org>
CC: Neal Liu <neal.liu@...iatek.com>, Rob Herring <robh+dt@...nel.org>,
Matthias Brugger <matthias.bgg@...il.com>,
<devicetree@...r.kernel.org>,
wsd_upstream <wsd_upstream@...iatek.com>,
linux-kernel <linux-kernel@...r.kernel.org>,
"moderated list:ARM/Mediatek SoC support"
<linux-mediatek@...ts.infradead.org>,
Linux ARM <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v2 2/2] soc: mediatek: devapc: add devapc-mt6873 driver
Hi Chun-Kuang,
On Sun, 2020-06-21 at 07:36 +0800, Chun-Kuang Hu wrote:
> Hi, Neal:
>
> Neal Liu <neal.liu@...iatek.com> 於 2020年6月20日 週六 上午11:18寫道：
> >
> > Hi Chun-Kuang,
> >
> > Thanks for your quick feedback.
> >
> > On Sat, 2020-06-20 at 00:25 +0800, Chun-Kuang Hu wrote:
> > > Hi, Neal:
> > >
> > > Neal Liu <neal.liu@...iatek.com> 於 2020年6月19日 週五 下午6:01寫道：
> > > >
> > > > MT6873 bus frabric provides TrustZone security support and data
> > > > protection to prevent slaves from being accessed by unexpected
> > > > masters.
> > > > The security violations are logged and sent to the processor for
> > > > further analysis or countermeasures.
> > > >
> > > > Any occurrence of security violation would raise an interrupt, and
> > > > it will be handled by devapc-mt6873 driver. The violation
> > > > information is printed in order to find the murderer.
> > > >
> > > > Signed-off-by: Neal Liu <neal.liu@...iatek.com>
> > > > ---
> > >
> > > [snip]
> > >
> > > > +
> > > > +/*
> > > > + * mtk_devapc_pd_get - get devapc pd_types of register address.
> > > > + *
> > > > + * Returns the value of reg addr
> > > > + */
> > > > +static void __iomem *mtk_devapc_pd_get(struct mtk_devapc_context *devapc_ctx,
> > > > + int slave_type,
> > > > + enum DEVAPC_PD_REG_TYPE pd_reg_type,
> > > > + u32 index)
> > > > +{
> > > > + struct mtk_devapc_vio_info *vio_info = devapc_ctx->soc->vio_info;
> > > > + u32 slave_type_num = devapc_ctx->soc->slave_type_num;
> > > > + const u32 *devapc_pds = devapc_ctx->soc->devapc_pds;
> > >
> > > devapc_pds = mt6873_devapc_pds;
> >
> > Are you saying all platform related variables & functions should assign
> > & call it directly in this common flow?
> > I don't think it's a good idea to go backwards since we already extract
> > the common out of it.
>
> I think we should "do one thing in one patch". When you mix two things
> into one patch, how does reviewer know each modification belong to
> first thing or second thing? For supporting multiple SoC, the patches
> sequence look like this:
>
> Patch 1: Add support SoC 1.
> Patch 2: Abstract function and variable for SoC 2.
> Patch 3: Add support SoC 2.
> Patch 4: Abstract function and variable for SoC 3.
> Patch 5: Add support SoC 3.
> Patch 6: Abstract function and variable for SoC 4.
> Patch 7: Add support SoC 4.
>
> In patch 1, you should not do any thing about abstraction, but you
> want to merge patch 2, 4, 6 into this patch, so this patch's title
> should be "Add support SoC 1 and abstract function and varible for SoC
> 2, SoC 3, and SoC 4"
>
Okay, I'll try to split driver to multiple patches for different
functionality. Thanks for suggestion.
> >
> > >
> > >
> > > > + void __iomem *reg;
> > > > +
> > > > + if (!devapc_pds)
> > >
> > > Never happen.
> > >
> > > > + return NULL;
> > > > +
> > > > + if ((slave_type < slave_type_num &&
> > > > + index < vio_info->vio_mask_sta_num[slave_type]) &&
> > > > + pd_reg_type < PD_REG_TYPE_NUM) {
> > >
> > > Always true.
> > >
> > > > + reg = devapc_ctx->devapc_pd_base[slave_type] +
> > > > + devapc_pds[pd_reg_type];
> > > > +
> > > > + if (pd_reg_type == VIO_MASK || pd_reg_type == VIO_STA)
> > > > + reg += 0x4 * index;
> > > > +
> > > > + } else {
> > > > + pr_err(PFX "Out Of Boundary, slave_type:0x%x/pd_reg_type:0x%x/index:0x%x\n",
> > > > + slave_type, pd_reg_type, index);
> > > > + return NULL;
> > > > + }
> > > > +
> > > > + return reg;
> > > > +}
> > > > +
> > >
> > > [snip]
> > >
> > > > +
> > > > +/*
> > > > + * start_devapc - initialize devapc status and start receiving interrupt
> > > > + * while devapc violation is triggered.
> > > > + */
> > > > +static void start_devapc(struct mtk_devapc_context *devapc_ctx)
> > > > +{
> > > > + u32 slave_type_num = devapc_ctx->soc->slave_type_num;
> > > > + const struct mtk_device_info **device_info;
> > > > + const struct mtk_device_num *ndevices;
> > > > + void __iomem *pd_vio_shift_sta_reg;
> > > > + void __iomem *pd_apc_con_reg;
> > > > + int slave_type, i, vio_idx, index;
> > > > + u32 vio_shift_sta;
> > > > +
> > > > + ndevices = devapc_ctx->soc->ndevices;
> > >
> > > ndevices = mtk6873_devices_num;
> > >
> > >
> > > > +
> > > > + device_info = devapc_ctx->soc->device_info;
> > > > +
> > > > + for (slave_type = 0; slave_type < slave_type_num; slave_type++) {
> > > > + pd_apc_con_reg = mtk_devapc_pd_get(devapc_ctx, slave_type,
> > > > + APC_CON, 0);
> > > > + pd_vio_shift_sta_reg = mtk_devapc_pd_get(devapc_ctx, slave_type,
> > > > + VIO_SHIFT_STA, 0);
> > > > +
> > > > + if (!pd_apc_con_reg || !pd_vio_shift_sta_reg || !device_info)
> > > > + return;
> > > > +
> > > > + /* Clear DEVAPC violation status */
> > > > + writel(BIT(31), pd_apc_con_reg);
> > > > +
> > > > + /* Clear violation shift status */
> > > > + vio_shift_sta = readl(pd_vio_shift_sta_reg);
> > > > + if (vio_shift_sta)
> > > > + writel(vio_shift_sta, pd_vio_shift_sta_reg);
> > > > +
> > > > + /* Clear type 2 violation status */
> > > > + check_type2_vio_status(devapc_ctx, slave_type, &vio_idx, &i);
> > > > +
> > > > + /* Clear violation status */
> > > > + for (i = 0; i < ndevices[slave_type].vio_slave_num; i++) {
> > > > + vio_idx = device_info[slave_type][i].vio_index;
> > > > + if ((check_vio_status(devapc_ctx, slave_type, vio_idx)
> > > > + == VIOLATION_TRIGGERED) &&
> > > > + clear_vio_status(devapc_ctx, slave_type,
> > > > + vio_idx)) {
> > > > + pr_warn(PFX "Clear vio status failed, slave_type:0x%x, vio_index:0x%x\n",
> > > > + slave_type, vio_idx);
> > > > +
> > > > + index = i;
> > > > + mtk_devapc_dump_vio_dbg(devapc_ctx, slave_type,
> > > > + &vio_idx, &index);
> > > > + i = index - 1;
> > > > + }
> > > > +
> > > > + mask_module_irq(devapc_ctx, slave_type, vio_idx, false);
> > > > + }
> > > > + }
> > > > +}
> > > > +
> > > > +static DEFINE_SPINLOCK(devapc_lock);
> > >
> > > Useless, so remove it.
> >
> > We use devapc_lock in below isr, what do you mean useless?
>
> We use spinlock because a thread context and irq context would access
> the same resource, but where is the thread context? If the thread
> context exist in another patch, move this spinlock to that patch.
>
> Regards,
> Chun-Kuang.
>
> >
> > >
> > > > +
> > > > +/*
> > > > + * devapc_violation_irq - the devapc Interrupt Service Routine (ISR) will dump
> > > > + * violation information including which master violates
> > > > + * access slave.
> > > > + */
> > > > +static irqreturn_t devapc_violation_irq(int irq_number,
> > > > + struct mtk_devapc_context *devapc_ctx)
> > > > +{
> > > > + u32 slave_type_num = devapc_ctx->soc->slave_type_num;
> > > > + const struct mtk_device_info **device_info;
> > > > + struct mtk_devapc_vio_info *vio_info;
> > > > + int slave_type, vio_idx, index;
> > > > + const char *vio_master;
> > > > + unsigned long flags;
> > > > + u8 perm;
> > > > +
> > > > + spin_lock_irqsave(&devapc_lock, flags);
> > > > +
> > > > + device_info = devapc_ctx->soc->device_info;
> > > > + vio_info = devapc_ctx->soc->vio_info;
> > > > + vio_idx = -1;
> > > > + index = -1;
> > > > +
> > > > + /* There are multiple DEVAPC_PD */
> > > > + for (slave_type = 0; slave_type < slave_type_num; slave_type++) {
> > > > + if (!check_type2_vio_status(devapc_ctx, slave_type, &vio_idx,
> > > > + &index))
> > > > + if (!mtk_devapc_dump_vio_dbg(devapc_ctx, slave_type,
> > > > + &vio_idx, &index))
> > > > + continue;
> > > > +
> > > > + /* Ensure that violation info are written before
> > > > + * further operations
> > > > + */
> > > > + smp_mb();
> > > > +
> > > > + mask_module_irq(devapc_ctx, slave_type, vio_idx, true);
> > > > +
> > > > + clear_vio_status(devapc_ctx, slave_type, vio_idx);
> > > > +
> > > > + perm = get_permission(devapc_ctx, slave_type, index,
> > > > + vio_info->domain_id);
> > > > +
> > > > + vio_master = devapc_ctx->soc->master_get
> > > > + (vio_info->master_id,
> > > > + vio_info->vio_addr,
> > > > + slave_type,
> > > > + vio_info->shift_sta_bit,
> > > > + vio_info->domain_id);
> > >
> > > Call mt6873_bus_id_to_master() directly.
> > >
> > > > +
> > > > + if (!vio_master)
> > > > + vio_master = "UNKNOWN_MASTER";
> > > > +
> > > > + pr_info(PFX "Violation - slave_type:0x%x, sys_index:0x%x, ctrl_index:0x%x, vio_index:0x%x\n",
> > > > + slave_type,
> > > > + device_info[slave_type][index].sys_index,
> > > > + device_info[slave_type][index].ctrl_index,
> > > > + device_info[slave_type][index].vio_index);
> > > > +
> > > > + pr_info(PFX "Violation Master: %s\n", vio_master);
> > > > +
> > > > + devapc_vio_reason(perm);
> > > > +
> > > > + mask_module_irq(devapc_ctx, slave_type, vio_idx, false);
> > > > + }
> > > > +
> > > > + spin_unlock_irqrestore(&devapc_lock, flags);
> > > > + return IRQ_HANDLED;
> > > > +}
> > > > +
> >
> > [snip]
> >
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