Re: [PATCH v3 4/6] iommu/exynos: Abstract non-common registers on different variants

From: Robin Murphy
Date: Fri Jul 15 2022 - 08:14:18 EST

On 2022-07-14 17:55, Sam Protsenko wrote:
At the moment the driver supports SysMMU v1..v5 versions. SysMMU v5 has
different register layout than SysMMU v1..v3. Instead of checking the
version each time before reading/writing the registers, let's create
corresponding register structure for each SysMMU version and set the
needed structure on init, checking the SysMMU version one single time.
This way is faster and more elegant.

No behavior changes from the user's point of view, it's only a
refactoring patch.

Signed-off-by: Sam Protsenko <semen.protsenko@xxxxxxxxxx>
Acked-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
Changes in v3:
- Added Marek's Acked-by tag
- Removed abstracting common regs, used plain readl/writel to access
those instead
- Used variant struct instead of array to keep non-common register
offsets

I'm a bit late, but just for the record I think the new approach in this version looks really good :)

Cheers,
Robin.

- Removed 0x1 value used as an offset for missing registers
- Merged __sysmmu_hw_info() into __sysmmu_get_version()
- Refactored __sysmmu_tlb_invalidate_entry() for "num_inv == 1" case
- Reworked the commit message w.r.t. all changes

Changes in v2:
- Reworked existing code (SysMMU v1..v5) to use this approach
- Extracted v7 registers to the separate patches
- Replaced MMU_REG() with corresponding SysMMU read/write functions
- Improved the comment for 0x1 offsets triggering an unaligned access
exception
- Removed support for VMID number, as only VMID=0 (default) is used
for now
- Renamed register index names to reflect the old SysMMU version
register names

drivers/iommu/exynos-iommu.c | 100 +++++++++++++++++++++--------------
1 file changed, 60 insertions(+), 40 deletions(-)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 494f7d7aa9c5..6a0299fe1722 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -148,26 +148,12 @@ static u32 lv2ent_offset(sysmmu_iova_t iova)
#define MAKE_MMU_VER(maj, min) ((((maj) & 0xF) << 7) | ((min) & 0x7F))
/* v1.x - v3.x registers */
-#define REG_MMU_FLUSH 0x00C
-#define REG_MMU_FLUSH_ENTRY 0x010
-#define REG_PT_BASE_ADDR 0x014
-#define REG_INT_STATUS 0x018
-#define REG_INT_CLEAR 0x01C
-
#define REG_PAGE_FAULT_ADDR 0x024
#define REG_AW_FAULT_ADDR 0x028
#define REG_AR_FAULT_ADDR 0x02C
#define REG_DEFAULT_SLAVE_ADDR 0x030
/* v5.x registers */
-#define REG_V5_PT_BASE_PFN 0x00C
-#define REG_V5_MMU_FLUSH_ALL 0x010
-#define REG_V5_MMU_FLUSH_ENTRY 0x014
-#define REG_V5_MMU_FLUSH_RANGE 0x018
-#define REG_V5_MMU_FLUSH_START 0x020
-#define REG_V5_MMU_FLUSH_END 0x024
-#define REG_V5_INT_STATUS 0x060
-#define REG_V5_INT_CLEAR 0x064
#define REG_V5_FAULT_AR_VA 0x070
#define REG_V5_FAULT_AW_VA 0x080
@@ -250,6 +236,21 @@ struct exynos_iommu_domain {
struct iommu_domain domain; /* generic domain data structure */
};
+/*
+ * SysMMU version specific data. Contains offsets for the registers which can
+ * be found in different SysMMU variants, but have different offset values.
+ */
+struct sysmmu_variant {
+ u32 pt_base; /* page table base address (physical) */
+ u32 flush_all; /* invalidate all TLB entries */
+ u32 flush_entry; /* invalidate specific TLB entry */
+ u32 flush_range; /* invalidate TLB entries in specified range */
+ u32 flush_start; /* start address of range invalidation */
+ u32 flush_end; /* end address of range invalidation */
+ u32 int_status; /* interrupt status information */
+ u32 int_clear; /* clear the interrupt */
+};
+
/*
* This structure hold all data of a single SYSMMU controller, this includes
* hw resources like registers and clocks, pointers and list nodes to connect
@@ -274,6 +275,30 @@ struct sysmmu_drvdata {
unsigned int version; /* our version */
struct iommu_device iommu; /* IOMMU core handle */
+ const struct sysmmu_variant *variant; /* version specific data */
+};
+
+#define SYSMMU_REG(data, reg) ((data)->sfrbase + (data)->variant->reg)
+
+/* SysMMU v1..v3 */
+static const struct sysmmu_variant sysmmu_v1_variant = {
+ .flush_all = 0x0c,
+ .flush_entry = 0x10,
+ .pt_base = 0x14,
+ .int_status = 0x18,
+ .int_clear = 0x1c,
+};
+
+/* SysMMU v5 */
+static const struct sysmmu_variant sysmmu_v5_variant = {
+ .pt_base = 0x0c,
+ .flush_all = 0x10,
+ .flush_entry = 0x14,
+ .flush_range = 0x18,
+ .flush_start = 0x20,
+ .flush_end = 0x24,
+ .int_status = 0x60,
+ .int_clear = 0x64,
};
static struct exynos_iommu_domain *to_exynos_domain(struct iommu_domain *dom)
@@ -304,10 +329,7 @@ static bool sysmmu_block(struct sysmmu_drvdata *data)
static void __sysmmu_tlb_invalidate(struct sysmmu_drvdata *data)
{
- if (MMU_MAJ_VER(data->version) < 5)
- writel(0x1, data->sfrbase + REG_MMU_FLUSH);
- else
- writel(0x1, data->sfrbase + REG_V5_MMU_FLUSH_ALL);
+ writel(0x1, SYSMMU_REG(data, flush_all));
}
static void __sysmmu_tlb_invalidate_entry(struct sysmmu_drvdata *data,
@@ -315,33 +337,30 @@ static void __sysmmu_tlb_invalidate_entry(struct sysmmu_drvdata *data,
{
unsigned int i;
- if (MMU_MAJ_VER(data->version) < 5) {
+ if (MMU_MAJ_VER(data->version) < 5 || num_inv == 1) {
for (i = 0; i < num_inv; i++) {
writel((iova & SPAGE_MASK) | 1,
- data->sfrbase + REG_MMU_FLUSH_ENTRY);
+ SYSMMU_REG(data, flush_entry));
iova += SPAGE_SIZE;
}
} else {
- if (num_inv == 1) {
- writel((iova & SPAGE_MASK) | 1,
- data->sfrbase + REG_V5_MMU_FLUSH_ENTRY);
- } else {
- writel((iova & SPAGE_MASK),
- data->sfrbase + REG_V5_MMU_FLUSH_START);
- writel((iova & SPAGE_MASK) + (num_inv - 1) * SPAGE_SIZE,
- data->sfrbase + REG_V5_MMU_FLUSH_END);
- writel(1, data->sfrbase + REG_V5_MMU_FLUSH_RANGE);
- }
+ writel(iova & SPAGE_MASK, SYSMMU_REG(data, flush_start));
+ writel((iova & SPAGE_MASK) + (num_inv - 1) * SPAGE_SIZE,
+ SYSMMU_REG(data, flush_end));
+ writel(0x1, SYSMMU_REG(data, flush_range));
}
}
static void __sysmmu_set_ptbase(struct sysmmu_drvdata *data, phys_addr_t pgd)
{
+ u32 pt_base;
+
if (MMU_MAJ_VER(data->version) < 5)
- writel(pgd, data->sfrbase + REG_PT_BASE_ADDR);
+ pt_base = pgd;
else
- writel(pgd >> SPAGE_ORDER, data->sfrbase + REG_V5_PT_BASE_PFN);
+ pt_base = pgd >> SPAGE_ORDER;
+ writel(pt_base, SYSMMU_REG(data, pt_base));
__sysmmu_tlb_invalidate(data);
}
@@ -378,6 +397,11 @@ 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));
+ if (MMU_MAJ_VER(data->version) < 5)
+ data->variant = &sysmmu_v1_variant;
+ else
+ data->variant = &sysmmu_v5_variant;
+
__sysmmu_disable_clocks(data);
}
@@ -405,19 +429,14 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
const struct sysmmu_fault_info *finfo;
unsigned int i, n, itype;
sysmmu_iova_t fault_addr;
- unsigned short reg_status, reg_clear;
int ret = -ENOSYS;
WARN_ON(!data->active);
if (MMU_MAJ_VER(data->version) < 5) {
- reg_status = REG_INT_STATUS;
- reg_clear = REG_INT_CLEAR;
finfo = sysmmu_faults;
n = ARRAY_SIZE(sysmmu_faults);
} else {
- reg_status = REG_V5_INT_STATUS;
- reg_clear = REG_V5_INT_CLEAR;
finfo = sysmmu_v5_faults;
n = ARRAY_SIZE(sysmmu_v5_faults);
}
@@ -426,7 +445,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
clk_enable(data->clk_master);
- itype = __ffs(readl(data->sfrbase + reg_status));
+ itype = __ffs(readl(SYSMMU_REG(data, int_status)));
for (i = 0; i < n; i++, finfo++)
if (finfo->bit == itype)
break;
@@ -443,7 +462,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
/* fault is not recovered by fault handler */
BUG_ON(ret != 0);
- writel(1 << itype, data->sfrbase + reg_clear);
+ writel(1 << itype, SYSMMU_REG(data, int_clear));
sysmmu_unblock(data);
@@ -622,6 +641,8 @@ static int exynos_sysmmu_probe(struct platform_device *pdev)
data->sysmmu = dev;
spin_lock_init(&data->lock);
+ __sysmmu_get_version(data);
+
ret = iommu_device_sysfs_add(&data->iommu, &pdev->dev, NULL,
dev_name(data->sysmmu));
if (ret)
@@ -633,7 +654,6 @@ 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;