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

[Tomasz Figa <t.figa-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>]

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.

> Signed-off-by: Cho KyongHo <pullip.cho-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> ---
>   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.

> +		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.

--
Best regards,
Tomasz