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Message-ID: <CAPLW+4nzxAP4jFxxWRTuXWHzEbpsZEVO7OAZH5A_V1Bda-tNBg@mail.gmail.com>
Date: Fri, 15 Jul 2022 15:44:39 +0300
From: Sam Protsenko <semen.protsenko@...aro.org>
To: Robin Murphy <robin.murphy@....com>
Cc: Marek Szyprowski <m.szyprowski@...sung.com>,
Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
Janghyuck Kim <janghyuck.kim@...sung.com>,
Cho KyongHo <pullip.cho@...sung.com>,
Daniel Mentz <danielmentz@...gle.com>,
David Virag <virag.david003@...il.com>,
Sumit Semwal <sumit.semwal@...aro.org>, iommu@...ts.linux.dev,
linux-arm-kernel@...ts.infradead.org,
linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 4/6] iommu/exynos: Abstract non-common registers on
different variants
On Fri, 15 Jul 2022 at 15:14, Robin Murphy <robin.murphy@....com> wrote:
>
> On 2022-07-14 17:55, Sam Protsenko wrote:
> > At the moment the driver supports SysMMU v1..v5 versions. SysMMU v5 has
> > different register layout than SysMMU v1..v3. Instead of checking the
> > version each time before reading/writing the registers, let's create
> > corresponding register structure for each SysMMU version and set the
> > needed structure on init, checking the SysMMU version one single time.
> > This way is faster and more elegant.
> >
> > No behavior changes from the user's point of view, it's only a
> > refactoring patch.
> >
> > Signed-off-by: Sam Protsenko <semen.protsenko@...aro.org>
> > Acked-by: Marek Szyprowski <m.szyprowski@...sung.com>
> > ---
> > Changes in v3:
> > - Added Marek's Acked-by tag
> > - Removed abstracting common regs, used plain readl/writel to access
> > those instead
> > - Used variant struct instead of array to keep non-common register
> > offsets
>
> I'm a bit late, but just for the record I think the new approach in this
> version looks really good :)
>
Thank you for the review, Robin!
> Cheers,
> Robin.
>
> > - Removed 0x1 value used as an offset for missing registers
> > - Merged __sysmmu_hw_info() into __sysmmu_get_version()
> > - Refactored __sysmmu_tlb_invalidate_entry() for "num_inv == 1" case
> > - Reworked the commit message w.r.t. all changes
> >
> > Changes in v2:
> > - Reworked existing code (SysMMU v1..v5) to use this approach
> > - Extracted v7 registers to the separate patches
> > - Replaced MMU_REG() with corresponding SysMMU read/write functions
> > - Improved the comment for 0x1 offsets triggering an unaligned access
> > exception
> > - Removed support for VMID number, as only VMID=0 (default) is used
> > for now
> > - Renamed register index names to reflect the old SysMMU version
> > register names
> >
> > drivers/iommu/exynos-iommu.c | 100 +++++++++++++++++++++--------------
> > 1 file changed, 60 insertions(+), 40 deletions(-)
> >
> > diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> > index 494f7d7aa9c5..6a0299fe1722 100644
> > --- a/drivers/iommu/exynos-iommu.c
> > +++ b/drivers/iommu/exynos-iommu.c
> > @@ -148,26 +148,12 @@ static u32 lv2ent_offset(sysmmu_iova_t iova)
> > #define MAKE_MMU_VER(maj, min) ((((maj) & 0xF) << 7) | ((min) & 0x7F))
> >
> > /* v1.x - v3.x registers */
> > -#define REG_MMU_FLUSH 0x00C
> > -#define REG_MMU_FLUSH_ENTRY 0x010
> > -#define REG_PT_BASE_ADDR 0x014
> > -#define REG_INT_STATUS 0x018
> > -#define REG_INT_CLEAR 0x01C
> > -
> > #define REG_PAGE_FAULT_ADDR 0x024
> > #define REG_AW_FAULT_ADDR 0x028
> > #define REG_AR_FAULT_ADDR 0x02C
> > #define REG_DEFAULT_SLAVE_ADDR 0x030
> >
> > /* v5.x registers */
> > -#define REG_V5_PT_BASE_PFN 0x00C
> > -#define REG_V5_MMU_FLUSH_ALL 0x010
> > -#define REG_V5_MMU_FLUSH_ENTRY 0x014
> > -#define REG_V5_MMU_FLUSH_RANGE 0x018
> > -#define REG_V5_MMU_FLUSH_START 0x020
> > -#define REG_V5_MMU_FLUSH_END 0x024
> > -#define REG_V5_INT_STATUS 0x060
> > -#define REG_V5_INT_CLEAR 0x064
> > #define REG_V5_FAULT_AR_VA 0x070
> > #define REG_V5_FAULT_AW_VA 0x080
> >
> > @@ -250,6 +236,21 @@ struct exynos_iommu_domain {
> > struct iommu_domain domain; /* generic domain data structure */
> > };
> >
> > +/*
> > + * SysMMU version specific data. Contains offsets for the registers which can
> > + * be found in different SysMMU variants, but have different offset values.
> > + */
> > +struct sysmmu_variant {
> > + u32 pt_base; /* page table base address (physical) */
> > + u32 flush_all; /* invalidate all TLB entries */
> > + u32 flush_entry; /* invalidate specific TLB entry */
> > + u32 flush_range; /* invalidate TLB entries in specified range */
> > + u32 flush_start; /* start address of range invalidation */
> > + u32 flush_end; /* end address of range invalidation */
> > + u32 int_status; /* interrupt status information */
> > + u32 int_clear; /* clear the interrupt */
> > +};
> > +
> > /*
> > * This structure hold all data of a single SYSMMU controller, this includes
> > * hw resources like registers and clocks, pointers and list nodes to connect
> > @@ -274,6 +275,30 @@ struct sysmmu_drvdata {
> > unsigned int version; /* our version */
> >
> > struct iommu_device iommu; /* IOMMU core handle */
> > + const struct sysmmu_variant *variant; /* version specific data */
> > +};
> > +
> > +#define SYSMMU_REG(data, reg) ((data)->sfrbase + (data)->variant->reg)
> > +
> > +/* SysMMU v1..v3 */
> > +static const struct sysmmu_variant sysmmu_v1_variant = {
> > + .flush_all = 0x0c,
> > + .flush_entry = 0x10,
> > + .pt_base = 0x14,
> > + .int_status = 0x18,
> > + .int_clear = 0x1c,
> > +};
> > +
> > +/* SysMMU v5 */
> > +static const struct sysmmu_variant sysmmu_v5_variant = {
> > + .pt_base = 0x0c,
> > + .flush_all = 0x10,
> > + .flush_entry = 0x14,
> > + .flush_range = 0x18,
> > + .flush_start = 0x20,
> > + .flush_end = 0x24,
> > + .int_status = 0x60,
> > + .int_clear = 0x64,
> > };
> >
> > static struct exynos_iommu_domain *to_exynos_domain(struct iommu_domain *dom)
> > @@ -304,10 +329,7 @@ static bool sysmmu_block(struct sysmmu_drvdata *data)
> >
> > static void __sysmmu_tlb_invalidate(struct sysmmu_drvdata *data)
> > {
> > - if (MMU_MAJ_VER(data->version) < 5)
> > - writel(0x1, data->sfrbase + REG_MMU_FLUSH);
> > - else
> > - writel(0x1, data->sfrbase + REG_V5_MMU_FLUSH_ALL);
> > + writel(0x1, SYSMMU_REG(data, flush_all));
> > }
> >
> > static void __sysmmu_tlb_invalidate_entry(struct sysmmu_drvdata *data,
> > @@ -315,33 +337,30 @@ static void __sysmmu_tlb_invalidate_entry(struct sysmmu_drvdata *data,
> > {
> > unsigned int i;
> >
> > - if (MMU_MAJ_VER(data->version) < 5) {
> > + if (MMU_MAJ_VER(data->version) < 5 || num_inv == 1) {
> > for (i = 0; i < num_inv; i++) {
> > writel((iova & SPAGE_MASK) | 1,
> > - data->sfrbase + REG_MMU_FLUSH_ENTRY);
> > + SYSMMU_REG(data, flush_entry));
> > iova += SPAGE_SIZE;
> > }
> > } else {
> > - if (num_inv == 1) {
> > - writel((iova & SPAGE_MASK) | 1,
> > - data->sfrbase + REG_V5_MMU_FLUSH_ENTRY);
> > - } else {
> > - writel((iova & SPAGE_MASK),
> > - data->sfrbase + REG_V5_MMU_FLUSH_START);
> > - writel((iova & SPAGE_MASK) + (num_inv - 1) * SPAGE_SIZE,
> > - data->sfrbase + REG_V5_MMU_FLUSH_END);
> > - writel(1, data->sfrbase + REG_V5_MMU_FLUSH_RANGE);
> > - }
> > + writel(iova & SPAGE_MASK, SYSMMU_REG(data, flush_start));
> > + writel((iova & SPAGE_MASK) + (num_inv - 1) * SPAGE_SIZE,
> > + SYSMMU_REG(data, flush_end));
> > + writel(0x1, SYSMMU_REG(data, flush_range));
> > }
> > }
> >
> > static void __sysmmu_set_ptbase(struct sysmmu_drvdata *data, phys_addr_t pgd)
> > {
> > + u32 pt_base;
> > +
> > if (MMU_MAJ_VER(data->version) < 5)
> > - writel(pgd, data->sfrbase + REG_PT_BASE_ADDR);
> > + pt_base = pgd;
> > else
> > - writel(pgd >> SPAGE_ORDER, data->sfrbase + REG_V5_PT_BASE_PFN);
> > + pt_base = pgd >> SPAGE_ORDER;
> >
> > + writel(pt_base, SYSMMU_REG(data, pt_base));
> > __sysmmu_tlb_invalidate(data);
> > }
> >
> > @@ -378,6 +397,11 @@ static void __sysmmu_get_version(struct sysmmu_drvdata *data)
> > dev_dbg(data->sysmmu, "hardware version: %d.%d\n",
> > MMU_MAJ_VER(data->version), MMU_MIN_VER(data->version));
> >
> > + if (MMU_MAJ_VER(data->version) < 5)
> > + data->variant = &sysmmu_v1_variant;
> > + else
> > + data->variant = &sysmmu_v5_variant;
> > +
> > __sysmmu_disable_clocks(data);
> > }
> >
> > @@ -405,19 +429,14 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
> > const struct sysmmu_fault_info *finfo;
> > unsigned int i, n, itype;
> > sysmmu_iova_t fault_addr;
> > - unsigned short reg_status, reg_clear;
> > int ret = -ENOSYS;
> >
> > WARN_ON(!data->active);
> >
> > if (MMU_MAJ_VER(data->version) < 5) {
> > - reg_status = REG_INT_STATUS;
> > - reg_clear = REG_INT_CLEAR;
> > finfo = sysmmu_faults;
> > n = ARRAY_SIZE(sysmmu_faults);
> > } else {
> > - reg_status = REG_V5_INT_STATUS;
> > - reg_clear = REG_V5_INT_CLEAR;
> > finfo = sysmmu_v5_faults;
> > n = ARRAY_SIZE(sysmmu_v5_faults);
> > }
> > @@ -426,7 +445,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
> >
> > clk_enable(data->clk_master);
> >
> > - itype = __ffs(readl(data->sfrbase + reg_status));
> > + itype = __ffs(readl(SYSMMU_REG(data, int_status)));
> > for (i = 0; i < n; i++, finfo++)
> > if (finfo->bit == itype)
> > break;
> > @@ -443,7 +462,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
> > /* fault is not recovered by fault handler */
> > BUG_ON(ret != 0);
> >
> > - writel(1 << itype, data->sfrbase + reg_clear);
> > + writel(1 << itype, SYSMMU_REG(data, int_clear));
> >
> > sysmmu_unblock(data);
> >
> > @@ -622,6 +641,8 @@ static int exynos_sysmmu_probe(struct platform_device *pdev)
> > data->sysmmu = dev;
> > spin_lock_init(&data->lock);
> >
> > + __sysmmu_get_version(data);
> > +
> > ret = iommu_device_sysfs_add(&data->iommu, &pdev->dev, NULL,
> > dev_name(data->sysmmu));
> > if (ret)
> > @@ -633,7 +654,6 @@ static int exynos_sysmmu_probe(struct platform_device *pdev)
> >
> > platform_set_drvdata(pdev, data);
> >
> > - __sysmmu_get_version(data);
> > if (PG_ENT_SHIFT < 0) {
> > if (MMU_MAJ_VER(data->version) < 5) {
> > PG_ENT_SHIFT = SYSMMU_PG_ENT_SHIFT;
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