Re: [PATCH 05/11] RISC-V: drivers/iommu/riscv: Add sysfs interface

From: Baolu Lu <baolu.lu@linux.intel.com>
To: Tomasz Jeznach <tjeznach@rivosinc.com>,
	Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Paul Walmsley <paul.walmsley@sifive.com>
Cc: Anup Patel <apatel@ventanamicro.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	linux@rivosinc.com, linux-kernel@vger.kernel.org,
	Sebastien Boeuf <seb@rivosinc.com>,
	iommu@lists.linux.dev, Palmer Dabbelt <palmer@dabbelt.com>,
	Nick Kossifidis <mick@ics.forth.gr>,
	linux-riscv@lists.infradead.org, baolu.lu@linux.intel.com
Subject: Re: [PATCH 05/11] RISC-V: drivers/iommu/riscv: Add sysfs interface
Date: Thu, 20 Jul 2023 20:50:43 +0800	[thread overview]
Message-ID: <2556751a-c439-bb69-a102-583dd985fc5e@linux.intel.com> (raw)
In-Reply-To: <610abe685f90870be52bc7c2ca45ab5235bd8eb4.1689792825.git.tjeznach@rivosinc.com>

On 2023/7/20 3:33, Tomasz Jeznach wrote:
> +#define sysfs_dev_to_iommu(dev) \
> +	container_of(dev_get_drvdata(dev), struct riscv_iommu_device, iommu)
> +
> +static ssize_t address_show(struct device *dev,
> +			    struct device_attribute *attr, char *buf)
> +{
> +	struct riscv_iommu_device *iommu = sysfs_dev_to_iommu(dev);
> +	return sprintf(buf, "%llx\n", iommu->reg_phys);

Use sysfs_emit() please.

> +}
> +
> +static DEVICE_ATTR_RO(address);
> +
> +#define ATTR_RD_REG32(name, offset)					\
> +	ssize_t reg_ ## name ## _show(struct device *dev,		\
> +			struct device_attribute *attr, char *buf)	\
> +{									\
> +	struct riscv_iommu_device *iommu = sysfs_dev_to_iommu(dev);	\
> +	return sprintf(buf, "0x%x\n",					\
> +			riscv_iommu_readl(iommu, offset));		\
> +}
> +
> +#define ATTR_RD_REG64(name, offset)					\
> +	ssize_t reg_ ## name ## _show(struct device *dev,		\
> +			struct device_attribute *attr, char *buf)	\
> +{									\
> +	struct riscv_iommu_device *iommu = sysfs_dev_to_iommu(dev);	\
> +	return sprintf(buf, "0x%llx\n",					\
> +			riscv_iommu_readq(iommu, offset));		\
> +}
> +
> +#define ATTR_WR_REG32(name, offset)					\
> +	ssize_t reg_ ## name ## _store(struct device *dev,		\
> +			struct device_attribute *attr,			\
> +			const char *buf, size_t len)			\
> +{									\
> +	struct riscv_iommu_device *iommu = sysfs_dev_to_iommu(dev);	\
> +	unsigned long val;						\
> +	int ret;							\
> +	ret = kstrtoul(buf, 0, &val);					\
> +	if (ret)							\
> +		return ret;						\
> +	riscv_iommu_writel(iommu, offset, val);				\
> +	return len;							\
> +}
> +
> +#define ATTR_WR_REG64(name, offset)					\
> +	ssize_t reg_ ## name ## _store(struct device *dev,		\
> +			struct device_attribute *attr,			\
> +			const char *buf, size_t len)			\
> +{									\
> +	struct riscv_iommu_device *iommu = sysfs_dev_to_iommu(dev);	\
> +	unsigned long long val;						\
> +	int ret;							\
> +	ret = kstrtoull(buf, 0, &val);					\
> +	if (ret)							\
> +		return ret;						\
> +	riscv_iommu_writeq(iommu, offset, val);				\
> +	return len;							\
> +}

So this allows users to change the registers through sysfs? How does
it synchronize with the iommu driver?

Best regards,
baolu

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