[RFC PATCH 06/18] drm/panthor: Derive MMU AS register addresses from base and stride
From: Karunika Choo
Date: Thu May 28 2026 - 11:20:09 EST
Move the MMU address-space register layout into the hardware description
by storing the MMU_AS base offset and per-AS stride in the Panthor HW
map.
Use those values to compute the iomem pointer for each AS slot and make
the MMU AS register definitions relative to the per-slot register window
instead of hard-coding the slot offset in every register macro.
This prepares the MMU code for GPUs where the MMU AS register region is
not at a fixed offset while keeping the existing register accesses
scoped to a single AS window.
Signed-off-by: Karunika Choo <karunika.choo@xxxxxxx>
---
drivers/gpu/drm/panthor/panthor_hw.c | 8 +++++
drivers/gpu/drm/panthor/panthor_hw.h | 8 +++++
drivers/gpu/drm/panthor/panthor_mmu.c | 35 ++++++++++++++--------
drivers/gpu/drm/panthor/panthor_mmu_regs.h | 23 ++++++--------
4 files changed, 47 insertions(+), 27 deletions(-)
diff --git a/drivers/gpu/drm/panthor/panthor_hw.c b/drivers/gpu/drm/panthor/panthor_hw.c
index 1f7fab4caf4d..e677f1a8f488 100644
--- a/drivers/gpu/drm/panthor/panthor_hw.c
+++ b/drivers/gpu/drm/panthor/panthor_hw.c
@@ -41,6 +41,10 @@ static struct panthor_hw panthor_hw_arch_v10 = {
.map = {
.gpu_control_base = 0x0,
.mcu_control_base = 0x700,
+ .mmu_as = {
+ .base = 0x2400,
+ .stride = 0x40,
+ },
},
};
@@ -54,6 +58,10 @@ static struct panthor_hw panthor_hw_arch_v14 = {
.gpu_control_base = 0x0,
.pwr_control_base = 0x800,
.mcu_control_base = 0x700,
+ .mmu_as = {
+ .base = 0x2400,
+ .stride = 0x40,
+ },
},
};
diff --git a/drivers/gpu/drm/panthor/panthor_hw.h b/drivers/gpu/drm/panthor/panthor_hw.h
index 58673a427bc9..0ae11b78c77e 100644
--- a/drivers/gpu/drm/panthor/panthor_hw.h
+++ b/drivers/gpu/drm/panthor/panthor_hw.h
@@ -38,6 +38,14 @@ struct panthor_hw_regmap {
/** @mcu_control_base: MCU_CONTROL base address */
u32 mcu_control_base;
+
+ struct {
+ /** @mmu_as.base: MMU_AS base address */
+ u32 base;
+
+ /** @mmu_as.stride: Stride between subsequent MMU_AS register blocks */
+ u32 stride;
+ } mmu_as;
};
/**
diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
index 48127313332f..9a64f977d28c 100644
--- a/drivers/gpu/drm/panthor/panthor_mmu.c
+++ b/drivers/gpu/drm/panthor/panthor_mmu.c
@@ -36,6 +36,7 @@
#include "panthor_gpu.h"
#include "panthor_gpu_regs.h"
#include "panthor_heap.h"
+#include "panthor_hw.h"
#include "panthor_mmu.h"
#include "panthor_mmu_regs.h"
#include "panthor_sched.h"
@@ -57,7 +58,7 @@ struct panthor_as_slot {
*/
struct panthor_mmu {
/** @iomem: CPU mapping of MMU_AS_CONTROL iomem region */
- void __iomem *iomem;
+ void __iomem *iomem[MAX_AS_SLOTS];
/** @irq: The MMU irq. */
struct panthor_irq irq;
@@ -528,7 +529,7 @@ static int wait_ready(struct panthor_device *ptdev, u32 as_nr)
/* Wait for the MMU status to indicate there is no active command, in
* case one is pending.
*/
- ret = gpu_read_relaxed_poll_timeout_atomic(mmu->iomem, AS_STATUS(as_nr), val,
+ ret = gpu_read_relaxed_poll_timeout_atomic(mmu->iomem[as_nr], AS_STATUS, val,
!(val & AS_STATUS_AS_ACTIVE), 10, 100000);
if (ret) {
@@ -546,7 +547,7 @@ static int as_send_cmd_and_wait(struct panthor_device *ptdev, u32 as_nr, u32 cmd
/* write AS_COMMAND when MMU is ready to accept another command */
status = wait_ready(ptdev, as_nr);
if (!status) {
- gpu_write(ptdev->mmu->iomem, AS_COMMAND(as_nr), cmd);
+ gpu_write(ptdev->mmu->iomem[as_nr], AS_COMMAND, cmd);
status = wait_ready(ptdev, as_nr);
}
@@ -599,9 +600,9 @@ static int panthor_mmu_as_enable(struct panthor_device *ptdev, u32 as_nr,
panthor_mmu_irq_enable_events(&ptdev->mmu->irq,
panthor_mmu_as_fault_mask(ptdev, as_nr));
- gpu_write64(mmu->iomem, AS_TRANSTAB(as_nr), transtab);
- gpu_write64(mmu->iomem, AS_MEMATTR(as_nr), memattr);
- gpu_write64(mmu->iomem, AS_TRANSCFG(as_nr), transcfg);
+ gpu_write64(mmu->iomem[as_nr], AS_TRANSTAB, transtab);
+ gpu_write64(mmu->iomem[as_nr], AS_MEMATTR, memattr);
+ gpu_write64(mmu->iomem[as_nr], AS_TRANSCFG, transcfg);
return as_send_cmd_and_wait(ptdev, as_nr, AS_COMMAND_UPDATE);
}
@@ -637,9 +638,9 @@ static int panthor_mmu_as_disable(struct panthor_device *ptdev, u32 as_nr,
if (recycle_slot)
return 0;
- gpu_write64(mmu->iomem, AS_TRANSTAB(as_nr), 0);
- gpu_write64(mmu->iomem, AS_MEMATTR(as_nr), 0);
- gpu_write64(mmu->iomem, AS_TRANSCFG(as_nr), AS_TRANSCFG_ADRMODE_UNMAPPED);
+ gpu_write64(mmu->iomem[as_nr], AS_TRANSTAB, 0);
+ gpu_write64(mmu->iomem[as_nr], AS_MEMATTR, 0);
+ gpu_write64(mmu->iomem[as_nr], AS_TRANSCFG, AS_TRANSCFG_ADRMODE_UNMAPPED);
return as_send_cmd_and_wait(ptdev, as_nr, AS_COMMAND_UPDATE);
}
@@ -1739,7 +1740,7 @@ static int panthor_vm_lock_region(struct panthor_vm *vm, u64 start, u64 size)
mutex_lock(&ptdev->mmu->as.slots_lock);
if (vm->as.id >= 0 && size) {
/* Lock the region that needs to be updated */
- gpu_write64(ptdev->mmu->iomem, AS_LOCKADDR(vm->as.id),
+ gpu_write64(ptdev->mmu->iomem[vm->as.id], AS_LOCKADDR,
pack_region_range(ptdev, &start, &size));
/* If the lock succeeded, update the locked_region info. */
@@ -1801,8 +1802,8 @@ static void panthor_mmu_irq_handler(struct panthor_device *ptdev, u32 status)
u32 access_type;
u32 source_id;
- fault_status = gpu_read(mmu->iomem, AS_FAULTSTATUS(as));
- addr = gpu_read64(mmu->iomem, AS_FAULTADDRESS(as));
+ fault_status = gpu_read(mmu->iomem[as], AS_FAULTSTATUS);
+ addr = gpu_read64(mmu->iomem[as], AS_FAULTADDRESS);
/* decode the fault status */
exception_type = fault_status & 0xFF;
@@ -3237,8 +3238,11 @@ static void panthor_mmu_release_wq(struct drm_device *ddev, void *res)
int panthor_mmu_init(struct panthor_device *ptdev)
{
u32 va_bits = GPU_MMU_FEATURES_VA_BITS(ptdev->gpu_info.mmu_features);
+ unsigned long as_present_mask = ptdev->gpu_info.as_present;
+ struct panthor_hw_regmap *regmap = &ptdev->hw->map;
struct panthor_mmu *mmu;
int ret, irq;
+ u32 as_id;
mmu = drmm_kzalloc(&ptdev->base, sizeof(*mmu), GFP_KERNEL);
if (!mmu)
@@ -3255,7 +3259,12 @@ int panthor_mmu_init(struct panthor_device *ptdev)
if (ret)
return ret;
- mmu->iomem = ptdev->iomem + MMU_AS_BASE;
+ for_each_set_bit(as_id, &as_present_mask, MAX_AS_SLOTS) {
+ u64 offset = regmap->mmu_as.base + (regmap->mmu_as.stride * as_id);
+
+ mmu->iomem[as_id] = ptdev->iomem + offset;
+ }
+
ptdev->mmu = mmu;
irq = platform_get_irq_byname(to_platform_device(ptdev->base.dev), "mmu");
diff --git a/drivers/gpu/drm/panthor/panthor_mmu_regs.h b/drivers/gpu/drm/panthor/panthor_mmu_regs.h
index 4e32ab931949..9d3747601e69 100644
--- a/drivers/gpu/drm/panthor/panthor_mmu_regs.h
+++ b/drivers/gpu/drm/panthor/panthor_mmu_regs.h
@@ -10,13 +10,8 @@
/* AS_COMMAND register commands */
-#define MMU_AS_BASE 0x2400
-
-#define MMU_AS_SHIFT 6
-#define MMU_AS(as) ((as) << MMU_AS_SHIFT)
-
-#define AS_TRANSTAB(as) (MMU_AS(as) + 0x0)
-#define AS_MEMATTR(as) (MMU_AS(as) + 0x8)
+#define AS_TRANSTAB 0x0
+#define AS_MEMATTR 0x8
#define AS_MEMATTR_AARCH64_INNER_ALLOC_IMPL (2 << 2)
#define AS_MEMATTR_AARCH64_INNER_ALLOC_EXPL(w, r) ((3 << 2) | \
((w) ? BIT(0) : 0) | \
@@ -28,8 +23,8 @@
#define AS_MEMATTR_AARCH64_INNER_OUTER_NC (1 << 6)
#define AS_MEMATTR_AARCH64_INNER_OUTER_WB (2 << 6)
#define AS_MEMATTR_AARCH64_FAULT (3 << 6)
-#define AS_LOCKADDR(as) (MMU_AS(as) + 0x10)
-#define AS_COMMAND(as) (MMU_AS(as) + 0x18)
+#define AS_LOCKADDR 0x10
+#define AS_COMMAND 0x18
#define AS_COMMAND_NOP 0
#define AS_COMMAND_UPDATE 1
#define AS_COMMAND_LOCK 2
@@ -37,16 +32,16 @@
#define AS_COMMAND_FLUSH_PT 4
#define AS_COMMAND_FLUSH_MEM 5
#define AS_LOCK_REGION_MIN_SIZE (1ULL << 15)
-#define AS_FAULTSTATUS(as) (MMU_AS(as) + 0x1C)
+#define AS_FAULTSTATUS 0x1C
#define AS_FAULTSTATUS_ACCESS_TYPE_MASK (0x3 << 8)
#define AS_FAULTSTATUS_ACCESS_TYPE_ATOMIC (0x0 << 8)
#define AS_FAULTSTATUS_ACCESS_TYPE_EX (0x1 << 8)
#define AS_FAULTSTATUS_ACCESS_TYPE_READ (0x2 << 8)
#define AS_FAULTSTATUS_ACCESS_TYPE_WRITE (0x3 << 8)
-#define AS_FAULTADDRESS(as) (MMU_AS(as) + 0x20)
-#define AS_STATUS(as) (MMU_AS(as) + 0x28)
+#define AS_FAULTADDRESS 0x20
+#define AS_STATUS 0x28
#define AS_STATUS_AS_ACTIVE BIT(0)
-#define AS_TRANSCFG(as) (MMU_AS(as) + 0x30)
+#define AS_TRANSCFG 0x30
#define AS_TRANSCFG_ADRMODE_UNMAPPED (1 << 0)
#define AS_TRANSCFG_ADRMODE_IDENTITY (2 << 0)
#define AS_TRANSCFG_ADRMODE_AARCH64_4K (6 << 0)
@@ -64,6 +59,6 @@
#define AS_TRANSCFG_DISABLE_AF_FAULT BIT(34)
#define AS_TRANSCFG_WXN BIT(35)
#define AS_TRANSCFG_XREADABLE BIT(36)
-#define AS_FAULTEXTRA(as) (MMU_AS(as) + 0x38)
+#define AS_FAULTEXTRA 0x38
#endif /* __PANTHOR_MMU_REGS_H__ */
--
2.43.0