[PATCH 3/4] iommu/exynos: Use lookup based approach to access v7 registers

[Sam Protsenko]

SysMMU v7 might have different register layouts (VM capable or non-VM
capable). Check which layout is implemented in current SysMMU module and
prepare the corresponding register table for futher usage. This way is
faster and more elegant than checking corresponding condition (if it's
VM or non-VM SysMMU) each time before accessing v7 registers. For now
the register table contains only most basic registers needed to add the
SysMMU v7 support.

This patch is based on downstream work of next authors:
  - Janghyuck Kim <janghyuck.kim at samsung.com>
  - Daniel Mentz <danielmentz at google.com>

Signed-off-by: Sam Protsenko <semen.protsenko at linaro.org>
---
 drivers/iommu/exynos-iommu.c | 46 ++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index df6ddbebbe2b..47017e8945c5 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -180,6 +180,47 @@ static u32 lv2ent_offset(sysmmu_iova_t iova)
 
 #define has_sysmmu(dev)		(dev_iommu_priv_get(dev) != NULL)
 
+#define MMU_REG(data, idx)		\
+	((data)->sfrbase + (data)->regs[idx].off)
+#define MMU_VM_REG(data, idx, vmid)	\
+	(MMU_REG(data, idx) + (vmid) * (data)->regs[idx].mult)
+
+enum {
+	REG_SET_NON_VM,
+	REG_SET_VM,
+	MAX_REG_SET
+};
+
+enum {
+	IDX_CTRL_VM,
+	IDX_CFG_VM,
+	IDX_FLPT_BASE,
+	IDX_ALL_INV,
+	MAX_REG_IDX
+};
+
+struct sysmmu_vm_reg {
+	unsigned int off;	/* register offset */
+	unsigned int mult;	/* VM index offset multiplier */
+};
+
+static const struct sysmmu_vm_reg sysmmu_regs[MAX_REG_SET][MAX_REG_IDX] = {
+	/* Default register set (non-VM) */
+	{
+		/*
+		 * SysMMUs without VM support do not have CTRL_VM and CFG_VM
+		 * registers. Setting the offsets to 1 will trigger an unaligned
+		 * access exception.
+		 */
+		{0x1}, {0x1}, {0x000c}, {0x0010},
+	},
+	/* VM capable register set */
+	{
+		{0x8000, 0x1000}, {0x8004, 0x1000}, {0x800c, 0x1000},
+		{0x8010, 0x1000},
+	},
+};
+
 static struct device *dma_dev;
 static struct kmem_cache *lv2table_kmem_cache;
 static sysmmu_pte_t *zero_lv2_table;
@@ -284,6 +325,7 @@ struct sysmmu_drvdata {
 
 	/* v7 fields */
 	bool has_vcr;			/* virtual machine control register */
+	const struct sysmmu_vm_reg *regs; /* register set */
 };
 
 static struct exynos_iommu_domain *to_exynos_domain(struct iommu_domain *dom)
@@ -407,6 +449,10 @@ static void sysmmu_get_hw_info(struct sysmmu_drvdata *data)
 	__sysmmu_get_version(data);
 	if (MMU_MAJ_VER(data->version) >= 7 && __sysmmu_has_capa1(data))
 		__sysmmu_get_vcr(data);
+	if (data->has_vcr)
+		data->regs = sysmmu_regs[REG_SET_VM];
+	else
+		data->regs = sysmmu_regs[REG_SET_NON_VM];
 
 	__sysmmu_disable_clocks(data);
 }
-- 
2.30.2