linux-kernel - [PATCH v2 5/7] iommu/exynos: Check if SysMMU v7 has VM registers

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Date:   Mon, 11 Jul 2022 02:06:01 +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>,
        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: [PATCH v2 5/7] 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>
---
Changes in v2:
  - Removed the 'const' qualifier for local non-pointer variables

 drivers/iommu/exynos-iommu.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 0cb1ce10db51..48681189ccf8 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_VERSION		0x034
 
@@ -154,6 +157,10 @@ 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)
 
 enum {
@@ -298,6 +305,9 @@ struct sysmmu_drvdata {
 
 	struct iommu_device iommu;	/* IOMMU core handle */
 	const unsigned int *regs;	/* register set */
+
+	/* v7 fields */
+	bool has_vcr;			/* virtual machine control register */
 };
 
 static struct exynos_iommu_domain *to_exynos_domain(struct iommu_domain *dom)
@@ -411,11 +421,27 @@ static void __sysmmu_get_version(struct sysmmu_drvdata *data)
 		MMU_MAJ_VER(data->version), MMU_MIN_VER(data->version));
 }
 
+static bool __sysmmu_has_capa1(struct sysmmu_drvdata *data)
+{
+	u32 capa0 = readl(data->sfrbase + REG_V7_CAPA0);
+
+	return capa0 & CAPA0_CAPA1_EXIST;
+}
+
+static void __sysmmu_get_vcr(struct sysmmu_drvdata *data)
+{
+	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);
 	if (MMU_MAJ_VER(data->version) < 5)
 		data->regs = sysmmu_regs[REG_SET_V1];
 	else
-- 
2.30.2