Re: [PATCH v11 08/27] iommu/exynos: always use a single clock descriptor

From: Cho KyongHo
Date: Tue Mar 18 2014 - 06:32:00 EST

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On Fri, 14 Mar 2014 14:07:32 +0100, Tomasz Figa wrote:
> Hi KyongHo,
>
> On 14.03.2014 06:05, Cho KyongHo wrote:
> > System MMU driver is changed to control only a single instance of
> > System MMU at a time. Since a single instance of System MMU has only
> > a single clock descriptor for its clock gating, there is no need to
> > obtain two or more clock descriptors.
> >
>
> This patch does much more than just making the driver use a single clock
> descriptor. Please update the subject and description accordingly.
>
Ok.

> > Signed-off-by: Cho KyongHo <pullip.cho@xxxxxxxxxxx>
> > ---
> > drivers/iommu/exynos-iommu.c | 223 ++++++++++++++----------------------------
> > 1 file changed, 72 insertions(+), 151 deletions(-)
> >
> > diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> > index 8dc7031..a4499b2 100644
> > --- a/drivers/iommu/exynos-iommu.c
> > +++ b/drivers/iommu/exynos-iommu.c
> > @@ -171,9 +171,8 @@ struct sysmmu_drvdata {
> > struct device *sysmmu; /* System MMU's device descriptor */
> > struct device *dev; /* Owner of system MMU */
> > char *dbgname;
> > - int nsfrs;
> > - void __iomem **sfrbases;
> > - struct clk *clk[2];
> > + void __iomem *sfrbase;
> > + struct clk *clk;
> > int activations;
> > rwlock_t lock;
> > struct iommu_domain *domain;
> > @@ -294,56 +293,39 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
> > {
> > /* SYSMMU is in blocked when interrupt occurred. */
> > struct sysmmu_drvdata *data = dev_id;
> > - struct resource *irqres;
> > - struct platform_device *pdev;
> > enum exynos_sysmmu_inttype itype;
> > unsigned long addr = -1;
> > -
> > - int i, ret = -ENOSYS;
> > + int ret = -ENOSYS;
> >
> > read_lock(&data->lock);
> >
> > WARN_ON(!is_sysmmu_active(data));
> >
> > - pdev = to_platform_device(data->sysmmu);
> > - for (i = 0; i < (pdev->num_resources / 2); i++) {
> > - irqres = platform_get_resource(pdev, IORESOURCE_IRQ, i);
> > - if (irqres && ((int)irqres->start == irq))
> > - break;
> > - }
> > -
> > - if (i == pdev->num_resources) {
> > + itype = (enum exynos_sysmmu_inttype)
> > + __ffs(__raw_readl(data->sfrbase + REG_INT_STATUS));
> > + if (WARN_ON(!((itype >= 0) && (itype < SYSMMU_FAULT_UNKNOWN))))
> > itype = SYSMMU_FAULT_UNKNOWN;
> > - } else {
> > - itype = (enum exynos_sysmmu_inttype)
> > - __ffs(__raw_readl(data->sfrbases[i] + REG_INT_STATUS));
> > - if (WARN_ON(!((itype >= 0) && (itype < SYSMMU_FAULT_UNKNOWN))))
> > - itype = SYSMMU_FAULT_UNKNOWN;
> > - else
> > - addr = __raw_readl(
> > - data->sfrbases[i] + fault_reg_offset[itype]);
> > - }
> > + else
> > + addr = __raw_readl(data->sfrbase + fault_reg_offset[itype]);
> >
> > if (data->domain)
> > - ret = report_iommu_fault(data->domain, data->dev,
> > - addr, itype);
> > + ret = report_iommu_fault(data->domain, data->dev, addr, itype);
> >
> > if ((ret == -ENOSYS) && data->fault_handler) {
> > unsigned long base = data->pgtable;
> > if (itype != SYSMMU_FAULT_UNKNOWN)
> > - base = __raw_readl(
> > - data->sfrbases[i] + REG_PT_BASE_ADDR);
> > + base = __raw_readl(data->sfrbase + REG_PT_BASE_ADDR);
> > ret = data->fault_handler(itype, base, addr);
> > }
> >
> > if (!ret && (itype != SYSMMU_FAULT_UNKNOWN))
> > - __raw_writel(1 << itype, data->sfrbases[i] + REG_INT_CLEAR);
> > + __raw_writel(1 << itype, data->sfrbase + REG_INT_CLEAR);
> > else
> > dev_dbg(data->sysmmu, "(%s) %s is not handled.\n",
> > data->dbgname, sysmmu_fault_name[itype]);
> >
> > if (itype != SYSMMU_FAULT_UNKNOWN)
> > - sysmmu_unblock(data->sfrbases[i]);
> > + sysmmu_unblock(data->sfrbase);
> >
> > read_unlock(&data->lock);
> >
> > @@ -354,20 +336,16 @@ static bool __exynos_sysmmu_disable(struct sysmmu_drvdata *data)
> > {
> > unsigned long flags;
> > bool disabled = false;
> > - int i;
> >
> > write_lock_irqsave(&data->lock, flags);
> >
> > if (!set_sysmmu_inactive(data))
> > goto finish;
> >
> > - for (i = 0; i < data->nsfrs; i++)
> > - __raw_writel(CTRL_DISABLE, data->sfrbases[i] + REG_MMU_CTRL);
> > + __raw_writel(CTRL_DISABLE, data->sfrbase + REG_MMU_CTRL);
> >
> > - if (data->clk[1])
> > - clk_disable(data->clk[1]);
> > - if (data->clk[0])
> > - clk_disable(data->clk[0]);
> > + if (data->clk)
>
> I know this is already in the driver, but checking (struct clk *) for
> NULL is incorrect. NULL is a valid pointer for dummy clocks on platforms
> which do not provide particular clocks, to make this transparent to
> drivers. IS_ERR() should be used to check whether a clock pointer is valid.
>
> This patch is changing all the clock code anyway, so this change could
> be squashed into it to fix this.
>
Ok. Thank you for the information.

> > + clk_disable(data->clk);
> >
> > disabled = true;
> > data->pgtable = 0;
> > @@ -393,7 +371,7 @@ finish:
> > static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
> > unsigned long pgtable, struct iommu_domain *domain)
> > {
> > - int i, ret = 0;
> > + int ret = 0;
> > unsigned long flags;
> >
> > write_lock_irqsave(&data->lock, flags);
> > @@ -410,17 +388,14 @@ static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
> > goto finish;
> > }
> >
> > - if (data->clk[0])
> > - clk_enable(data->clk[0]);
> > - if (data->clk[1])
> > - clk_enable(data->clk[1]);
> > + if (data->clk)
> > + clk_enable(data->clk);
> >
> > data->pgtable = pgtable;
> >
> > - for (i = 0; i < data->nsfrs; i++) {
> > - __sysmmu_set_ptbase(data->sfrbases[i], pgtable);
> > - __raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
> > - }
> > + __sysmmu_set_ptbase(data->sfrbase, pgtable);
> > +
> > + __raw_writel(CTRL_ENABLE, data->sfrbase + REG_MMU_CTRL);
> >
> > data->domain = domain;
> >
> > @@ -477,28 +452,26 @@ static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova,
> > read_lock_irqsave(&data->lock, flags);
> >
> > if (is_sysmmu_active(data)) {
> > - int i;
> > - for (i = 0; i < data->nsfrs; i++) {
> > - unsigned int maj;
> > - unsigned int num_inv = 1;
> > - maj = __raw_readl(data->sfrbases[i] + REG_MMU_VERSION);
> > - /*
> > - * L2TLB invalidation required
> > - * 4KB page: 1 invalidation
> > - * 64KB page: 16 invalidation
> > - * 1MB page: 64 invalidation
> > - * because it is set-associative TLB
> > - * with 8-way and 64 sets.
> > - * 1MB page can be cached in one of all sets.
> > - * 64KB page can be one of 16 consecutive sets.
> > - */
> > - if ((maj >> 28) == 2) /* major version number */
> > - num_inv = min_t(unsigned int, size / PAGE_SIZE, 64);
> > - if (sysmmu_block(data->sfrbases[i])) {
> > - __sysmmu_tlb_invalidate_entry(
> > - data->sfrbases[i], iova, num_inv);
> > - sysmmu_unblock(data->sfrbases[i]);
> > - }
> > + unsigned int maj;
> > + unsigned int num_inv = 1;
> > + maj = __raw_readl(data->sfrbase + REG_MMU_VERSION);
> > + /*
> > + * L2TLB invalidation required
> > + * 4KB page: 1 invalidation
> > + * 64KB page: 16 invalidation
> > + * 1MB page: 64 invalidation
> > + * because it is set-associative TLB
> > + * with 8-way and 64 sets.
> > + * 1MB page can be cached in one of all sets.
> > + * 64KB page can be one of 16 consecutive sets.
> > + */
> > + if ((maj >> 28) == 2) /* major version number */
> > + num_inv = min_t(unsigned int, size / PAGE_SIZE, 64);
> > +
> > + if (sysmmu_block(data->sfrbase)) {
> > + __sysmmu_tlb_invalidate_entry(data->sfrbase, iova,
> > + num_inv);
> > + sysmmu_unblock(data->sfrbase);
> > }
> > } else {
> > dev_dbg(data->sysmmu,
> > @@ -517,12 +490,9 @@ void exynos_sysmmu_tlb_invalidate(struct device *dev)
> > read_lock_irqsave(&data->lock, flags);
> >
> > if (is_sysmmu_active(data)) {
> > - int i;
> > - for (i = 0; i < data->nsfrs; i++) {
> > - if (sysmmu_block(data->sfrbases[i])) {
> > - __sysmmu_tlb_invalidate(data->sfrbases[i]);
> > - sysmmu_unblock(data->sfrbases[i]);
> > - }
> > + if (sysmmu_block(data->sfrbase)) {
> > + __sysmmu_tlb_invalidate(data->sfrbase);
> > + sysmmu_unblock(data->sfrbase);
> > }
> > } else {
> > dev_dbg(data->sysmmu,
> > @@ -535,11 +505,10 @@ void exynos_sysmmu_tlb_invalidate(struct device *dev)
> >
> > static int exynos_sysmmu_probe(struct platform_device *pdev)
> > {
> > - int i, ret;
> > - struct device *dev;
> > + int ret;
> > + struct device *dev = &pdev->dev;
> > struct sysmmu_drvdata *data;
> > -
> > - dev = &pdev->dev;
> > + struct resource *res;
> >
> > data = kzalloc(sizeof(*data), GFP_KERNEL);
> > if (!data) {
> > @@ -548,82 +517,39 @@ static int exynos_sysmmu_probe(struct platform_device *pdev)
> > goto err_alloc;
> > }
> >
> > - ret = dev_set_drvdata(dev, data);
> > - if (ret) {
> > - dev_dbg(dev, "Unabled to initialize driver data\n");
> > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > + if (!res) {
> > + dev_dbg(dev, "Unable to find IOMEM region\n");
> > + ret = -ENOENT;
> > goto err_init;
> > }
> >
> > - data->nsfrs = pdev->num_resources / 2;
> > - data->sfrbases = kmalloc(sizeof(*data->sfrbases) * data->nsfrs,
> > - GFP_KERNEL);
> > - if (data->sfrbases == NULL) {
> > - dev_dbg(dev, "Not enough memory\n");
> > - ret = -ENOMEM;
> > - goto err_init;
> > + data->sfrbase = ioremap(res->start, resource_size(res));
> > + if (!data->sfrbase) {
> > + dev_dbg(dev, "Unable to map IOMEM @ PA:%#x\n", res->start);
> > + ret = -ENOENT;
> > + goto err_res;
> > }
> >
> > - for (i = 0; i < data->nsfrs; i++) {
> > - struct resource *res;
> > - res = platform_get_resource(pdev, IORESOURCE_MEM, i);
> > - if (!res) {
> > - dev_dbg(dev, "Unable to find IOMEM region\n");
> > - ret = -ENOENT;
> > - goto err_res;
> > - }
> > -
> > - data->sfrbases[i] = ioremap(res->start, resource_size(res));
> > - if (!data->sfrbases[i]) {
> > - dev_dbg(dev, "Unable to map IOMEM @ PA:%#x\n",
> > - res->start);
> > - ret = -ENOENT;
> > - goto err_res;
> > - }
> > + ret = platform_get_irq(pdev, 0);
> > + if (ret <= 0) {
> > + dev_dbg(dev, "Unable to find IRQ resource\n");
> > + goto err_irq;
> > }
> >
> > - for (i = 0; i < data->nsfrs; i++) {
> > - ret = platform_get_irq(pdev, i);
> > - if (ret <= 0) {
> > - dev_dbg(dev, "Unable to find IRQ resource\n");
> > - goto err_irq;
> > - }
> > -
> > - ret = request_irq(ret, exynos_sysmmu_irq, 0,
> > - dev_name(dev), data);
> > - if (ret) {
> > - dev_dbg(dev, "Unabled to register interrupt handler\n");
> > - goto err_irq;
> > - }
> > + ret = request_irq(ret, exynos_sysmmu_irq, 0,
> > + dev_name(dev), data);
> > + if (ret) {
> > + dev_dbg(dev, "Unabled to register interrupt handler\n");
> > + goto err_irq;
> > }
> >
> > if (dev_get_platdata(dev)) {
> > - char *deli, *beg;
> > - struct sysmmu_platform_data *platdata = dev_get_platdata(dev);
> > -
> > - beg = platdata->clockname;
> > -
> > - for (deli = beg; (*deli != '\0') && (*deli != ','); deli++)
> > - /* NOTHING */;
> > -
> > - if (*deli == '\0')
> > - deli = NULL;
> > - else
> > - *deli = '\0';
> > -
> > - data->clk[0] = clk_get(dev, beg);
> > - if (IS_ERR(data->clk[0])) {
> > - data->clk[0] = NULL;
> > + data->clk = clk_get(dev, "sysmmu");
> > + if (IS_ERR(data->clk)) {
> > + data->clk = NULL;
>
> This is incorrect. IS_ERR() should be used through the driver and the
> error value here should not be replaced with NULL.
>
Ok.

Thank you for the review.

KyongHo.
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