linux-kernel - [PATCH v3 6/6] iommu/exynos: Enable default VM instance on SysMMU v7

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Date:   Thu, 14 Jul 2022 19:55:50 +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 v3 6/6] iommu/exynos: Enable default VM instance on SysMMU v7

In order to enable SysMMU v7 with VM register layout, at least the
default VM instance (n=0) must be enabled, in addition to enabling the
SysMMU itself. To do so, add corresponding write to MMU_CTRL_VM[0]
register, before writing to MMU_CTRL register.

Signed-off-by: Sam Protsenko <semen.protsenko@...aro.org>
Acked-by: Marek Szyprowski <m.szyprowski@...sung.com>
---
Changes in v3:
  - Reworked for using plain writel()
  - Added Marek's Acked-by tag

Changes in v2:
  - Extracted VM enabling code to the separate function
  - Used new SysMMU read/write functions to access the registers

 drivers/iommu/exynos-iommu.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index fc9ef3ff0057..8e18984a0c4f 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -135,6 +135,8 @@ 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 CTRL_VM_ENABLE			BIT(0)
+#define CTRL_VM_FAULT_MODE_STALL	BIT(3)
 #define CAPA0_CAPA1_EXIST		BIT(11)
 #define CAPA1_VCR_ENABLED		BIT(14)
 
@@ -163,6 +165,7 @@ static u32 lv2ent_offset(sysmmu_iova_t iova)
 /* v7.x registers */
 #define REG_V7_CAPA0		0x870
 #define REG_V7_CAPA1		0x874
+#define REG_V7_CTRL_VM		0x8000
 
 #define has_sysmmu(dev)		(dev_iommu_priv_get(dev) != NULL)
 
@@ -548,6 +551,18 @@ static void __sysmmu_init_config(struct sysmmu_drvdata *data)
 	writel(cfg, data->sfrbase + REG_MMU_CFG);
 }
 
+static void __sysmmu_enable_vid(struct sysmmu_drvdata *data)
+{
+	u32 ctrl;
+
+	if (MMU_MAJ_VER(data->version) < 7 || !data->has_vcr)
+		return;
+
+	ctrl = readl(data->sfrbase + REG_V7_CTRL_VM);
+	ctrl |= CTRL_VM_ENABLE | CTRL_VM_FAULT_MODE_STALL;
+	writel(ctrl, data->sfrbase + REG_V7_CTRL_VM);
+}
+
 static void __sysmmu_enable(struct sysmmu_drvdata *data)
 {
 	unsigned long flags;
@@ -558,6 +573,7 @@ static void __sysmmu_enable(struct sysmmu_drvdata *data)
 	writel(CTRL_BLOCK, data->sfrbase + REG_MMU_CTRL);
 	__sysmmu_init_config(data);
 	__sysmmu_set_ptbase(data, data->pgtable);
+	__sysmmu_enable_vid(data);
 	writel(CTRL_ENABLE, data->sfrbase + REG_MMU_CTRL);
 	data->active = true;
 	spin_unlock_irqrestore(&data->lock, flags);
-- 
2.30.2