linux-kernel - [PATCH 2/4] iommu/exynos: Check if SysMMU v7 has VM registers

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Date:   Sun,  3 Jul 2022 00:37:22 +0300
From:   Sam Protsenko <semen.protsenko@...aro.org>
To:     Marek Szyprowski <m.szyprowski@...sung.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc:     Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        Janghyuck Kim <janghyuck.kim@...sung.com>,
        Cho KyongHo <pullip.cho@...sung.com>,
        Daniel Mentz <danielmentz@...gle.com>,
        Sumit Semwal <sumit.semwal@...aro.org>,
        iommu@...ts.linux-foundation.org, iommu@...ts.linux.dev,
        linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/4] iommu/exynos: Check if SysMMU v7 has VM registers

SysMMU v7 can have Virtual Machine registers, which implement multiple
translation domains. The driver should know if it's true or not, as VM
registers shouldn't be accessed if not present. Read corresponding
capabilities register to obtain that info, and store it in driver data.

Signed-off-by: Sam Protsenko <semen.protsenko@...aro.org>
---
 drivers/iommu/exynos-iommu.c | 42 ++++++++++++++++++++++++++++++------
 1 file changed, 36 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 28f8c8d93aa3..df6ddbebbe2b 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -135,6 +135,9 @@ static u32 lv2ent_offset(sysmmu_iova_t iova)
 #define CFG_SYSSEL	(1 << 22) /* System MMU 3.2 only */
 #define CFG_FLPDCACHE	(1 << 20) /* System MMU 3.2+ only */
 
+#define CAPA0_CAPA1_EXIST		BIT(11)
+#define CAPA1_VCR_ENABLED		BIT(14)
+
 /* common registers */
 #define REG_MMU_CTRL		0x000
 #define REG_MMU_CFG		0x004
@@ -171,6 +174,10 @@ static u32 lv2ent_offset(sysmmu_iova_t iova)
 #define REG_V5_FAULT_AR_VA	0x070
 #define REG_V5_FAULT_AW_VA	0x080
 
+/* v7.x registers */
+#define REG_V7_CAPA0		0x870
+#define REG_V7_CAPA1		0x874
+
 #define has_sysmmu(dev)		(dev_iommu_priv_get(dev) != NULL)
 
 static struct device *dma_dev;
@@ -274,6 +281,9 @@ struct sysmmu_drvdata {
 	unsigned int version;		/* our version */
 
 	struct iommu_device iommu;	/* IOMMU core handle */
+
+	/* v7 fields */
+	bool has_vcr;			/* virtual machine control register */
 };
 
 static struct exynos_iommu_domain *to_exynos_domain(struct iommu_domain *dom)
@@ -364,11 +374,7 @@ static void __sysmmu_disable_clocks(struct sysmmu_drvdata *data)
 
 static void __sysmmu_get_version(struct sysmmu_drvdata *data)
 {
-	u32 ver;
-
-	__sysmmu_enable_clocks(data);
-
-	ver = readl(data->sfrbase + REG_MMU_VERSION);
+	const u32 ver = readl(data->sfrbase + REG_MMU_VERSION);
 
 	/* controllers on some SoCs don't report proper version */
 	if (ver == 0x80000001u)
@@ -378,6 +384,29 @@ 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));
+}
+
+static bool __sysmmu_has_capa1(struct sysmmu_drvdata *data)
+{
+	const u32 capa0 = readl(data->sfrbase + REG_V7_CAPA0);
+
+	return capa0 & CAPA0_CAPA1_EXIST;
+}
+
+static void __sysmmu_get_vcr(struct sysmmu_drvdata *data)
+{
+	const u32 capa1 = readl(data->sfrbase + REG_V7_CAPA1);
+
+	data->has_vcr = capa1 & CAPA1_VCR_ENABLED;
+}
+
+static void sysmmu_get_hw_info(struct sysmmu_drvdata *data)
+{
+	__sysmmu_enable_clocks(data);
+
+	__sysmmu_get_version(data);
+	if (MMU_MAJ_VER(data->version) >= 7 && __sysmmu_has_capa1(data))
+		__sysmmu_get_vcr(data);
 
 	__sysmmu_disable_clocks(data);
 }
@@ -623,6 +652,8 @@ static int exynos_sysmmu_probe(struct platform_device *pdev)
 	data->sysmmu = dev;
 	spin_lock_init(&data->lock);
 
+	sysmmu_get_hw_info(data);
+
 	ret = iommu_device_sysfs_add(&data->iommu, &pdev->dev, NULL,
 				     dev_name(data->sysmmu));
 	if (ret)
@@ -634,7 +665,6 @@ 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;
-- 
2.30.2