[PATCH v2 0/6] riscv: Make IPI_MAX visible and use it consistently

[PATCH v2 0/6] riscv: Make IPI_MAX visible and use it consistently

[Guo Ren]

This series removes the implicit assumption that RISC-V supports exactly
eight IPI message types.

Currently, the SBI, CLINT and ACLINT SSWI IPI providers use
BITS_PER_BYTE when sizing the generic IPI mux, while IMSIC carries a
separate IMSIC_NR_IPI definition set to 8. These values happen to match
IPI_MAX today, but neither is the proper source of truth for the number
of RISC-V IPI message types.

Move enum ipi_message_type to asm/smp.h so IPI providers can use IPI_MAX
directly, then replace the BITS_PER_BYTE and IMSIC_NR_IPI uses with
IPI_MAX.

This also makes adding future RISC-V IPI message types independent of
the current eight-entry assumption.

A follow-up patch renames the MediaTek VPU mailbox terminator from
IPI_MAX to IPI_VPU_MAX. That token belongs to the VPU firmware IPI id
enum and should follow the same prefixed convention as IPI_VPU_INIT
(and SCP_IPI_MAX on the SCP side), instead of reusing the generic
IPI_MAX name.

---
GUO Ren (XuanTie) (4):
      clocksource: clint: Use IPI_MAX for IPI muxing
      irqchip/aclint-sswi: Use IPI_MAX for IPI muxing
      irqchip/imsic: Use IPI_MAX instead of IMSIC_NR_IPI
      media: mtk-vpu: rename IPI_MAX to IPI_VPU_MAX

tip-bot2 for GUO Ren (XuanTie) (2):
      riscv: smp: Move enum ipi_message_type to asm/smp.h
      riscv: sbi: Use IPI_MAX for SBI IPI muxing

 arch/riscv/include/asm/smp.h                  | 12 ++++++++++++
 arch/riscv/kernel/sbi-ipi.c                   |  4 ++--
 arch/riscv/kernel/smp.c                       | 12 ------------
 drivers/clocksource/timer-clint.c             |  4 ++--
 drivers/irqchip/irq-aclint-sswi.c             |  4 ++--
 drivers/irqchip/irq-riscv-imsic-early.c       |  4 ++--
 drivers/irqchip/irq-riscv-imsic-state.h       |  1 -
 drivers/media/platform/mediatek/vpu/mtk_vpu.c | 12 ++++++------
 drivers/media/platform/mediatek/vpu/mtk_vpu.h |  4 ++--
 9 files changed, 28 insertions(+), 29 deletions(-)
---
base-commit: 08df884136f1c1197bab2a27814404fd329d9aac
change-id: 20260911-ipi_max-ff71eeadf6fd

Best regards,
--  
GUO Ren (XuanTie) <guoren@kernel.org>

[PATCH v2 1/6] riscv: smp: Move enum ipi_message_type to asm/smp.h

[Guo Ren]

From: "tip-bot2 for GUO Ren (XuanTie)" <tip-bot2@linutronix.de>

The following commit has been merged into the irq/drivers branch of tip:

Commit-ID:     1ae91dc397eb1dbc0f4fc6b96f2481cbc02fe0f9
Gitweb:        https://git.kernel.org/tip/1ae91dc397eb1dbc0f4fc6b96f2481cbc02fe0f9
Author:        GUO Ren (XuanTie) <guoren@kernel.org>
AuthorDate:    Sun, 16 Aug 2026 07:00:45
Committer:     Thomas Gleixner <tglx@kernel.org>
CommitterDate: Fri, 04 Sep 2026 15:34:34 +02:00

riscv: smp: Move enum ipi_message_type to asm/smp.h

The IPI message type enumeration (and therefore IPI_MAX) is currently
private to arch/riscv/kernel/smp.c.  Several IPI providers need to know
the exact number of IPIs that the architecture requires, so move the
enum into the public header.

This is a pure code movement with no functional change.

Signed-off-by: GUO Ren (XuanTie) <guoren@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Radu Rendec <radu@rendec.net>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://patch.msgid.link/20260816070049.2097442-2-guoren@kernel.org
---
 arch/riscv/include/asm/smp.h | 12 ++++++++++++
 arch/riscv/kernel/smp.c      | 12 ------------
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
index 0ecc67641b09..bed39fff1f8a 100644
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -15,6 +15,18 @@
 struct seq_file;
 extern unsigned long boot_cpu_hartid;
 
+enum ipi_message_type {
+	IPI_RESCHEDULE,
+	IPI_CALL_FUNC,
+	IPI_CPU_STOP,
+	IPI_CPU_CRASH_STOP,
+	IPI_IRQ_WORK,
+	IPI_TIMER,
+	IPI_CPU_BACKTRACE,
+	IPI_KGDB_ROUNDUP,
+	IPI_MAX
+};
+
 #ifdef CONFIG_SMP
 
 #include <linux/jump_label.h>
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index fa66f9c97d74..8930b62b15e7 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -28,18 +28,6 @@
 #include <asm/cacheflush.h>
 #include <asm/cpu_ops.h>
 
-enum ipi_message_type {
-	IPI_RESCHEDULE,
-	IPI_CALL_FUNC,
-	IPI_CPU_STOP,
-	IPI_CPU_CRASH_STOP,
-	IPI_IRQ_WORK,
-	IPI_TIMER,
-	IPI_CPU_BACKTRACE,
-	IPI_KGDB_ROUNDUP,
-	IPI_MAX
-};
-
 static const char * const ipi_names[] = {
 	[IPI_RESCHEDULE]	= "Rescheduling interrupts",
 	[IPI_CALL_FUNC]		= "Function call interrupts",

-- 
2.43.0

[PATCH v2 2/6] riscv: sbi: Use IPI_MAX for SBI IPI muxing

[Guo Ren]

From: "tip-bot2 for GUO Ren (XuanTie)" <tip-bot2@linutronix.de>

The following commit has been merged into the irq/drivers branch of tip:

Commit-ID:     2a0d49514f297baee259b19fb5553b538aa67d10
Gitweb:        https://git.kernel.org/tip/2a0d49514f297baee259b19fb5553b538aa67d10
Author:        GUO Ren (XuanTie) <guoren@kernel.org>
AuthorDate:    Sun, 16 Aug 2026 07:00:46
Committer:     Thomas Gleixner <tglx@kernel.org>
CommitterDate: Fri, 04 Sep 2026 15:34:34 +02:00

riscv: sbi: Use IPI_MAX for SBI IPI muxing

Now that IPI_MAX is visible from <asm/smp.h>, replace the hard-coded
BITS_PER_BYTE with the proper symbolic constant in the SBI IPI
extension driver.

No functional change; IPI_MAX is still 8.

Signed-off-by: GUO Ren (XuanTie) <guoren@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://patch.msgid.link/20260816070049.2097442-3-guoren@kernel.org
---
 arch/riscv/kernel/sbi-ipi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/kernel/sbi-ipi.c b/arch/riscv/kernel/sbi-ipi.c
index 0cc5559c08d8..eeec178a9b95 100644
--- a/arch/riscv/kernel/sbi-ipi.c
+++ b/arch/riscv/kernel/sbi-ipi.c
@@ -57,7 +57,7 @@ void __init sbi_ipi_init(void)
 		return;
 	}
 
-	virq = ipi_mux_create(BITS_PER_BYTE, sbi_send_ipi);
+	virq = ipi_mux_create(IPI_MAX, sbi_send_ipi);
 	if (virq <= 0) {
 		pr_err("unable to create muxed IPIs\n");
 		irq_dispose_mapping(sbi_ipi_virq);
@@ -75,7 +75,7 @@ void __init sbi_ipi_init(void)
 			  "irqchip/sbi-ipi:starting",
 			  sbi_ipi_starting_cpu, NULL);
 
-	riscv_ipi_set_virq_range(virq, BITS_PER_BYTE);
+	riscv_ipi_set_virq_range(virq, IPI_MAX);
 	pr_info("providing IPIs using SBI IPI extension\n");
 
 	/*

-- 
2.43.0

[PATCH v2 3/6] clocksource: clint: Use IPI_MAX for IPI muxing

[GUO Ren (XuanTie)]

Replace the hard-coded BITS_PER_BYTE with IPI_MAX now that the
constant is exported from riscv asm/smp.h.

Signed-off-by: GUO Ren (XuanTie) <guoren@kernel.org>
---
 drivers/clocksource/timer-clint.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/clocksource/timer-clint.c b/drivers/clocksource/timer-clint.c
index 0bdd9d7ec545..e56eee7e3781 100644
--- a/drivers/clocksource/timer-clint.c
+++ b/drivers/clocksource/timer-clint.c
@@ -243,7 +243,7 @@ static int __init clint_timer_init_dt(struct device_node *np)
 	}
 
 #ifdef CONFIG_SMP
-	rc = ipi_mux_create(BITS_PER_BYTE, clint_send_ipi);
+	rc = ipi_mux_create(IPI_MAX, clint_send_ipi);
 	if (rc <= 0) {
 		pr_err("unable to create muxed IPIs\n");
 		rc = (rc < 0) ? rc : -ENODEV;
@@ -251,7 +251,7 @@ static int __init clint_timer_init_dt(struct device_node *np)
 	}
 
 	irq_set_chained_handler(clint_ipi_irq, clint_ipi_interrupt);
-	riscv_ipi_set_virq_range(rc, BITS_PER_BYTE);
+	riscv_ipi_set_virq_range(rc, IPI_MAX);
 	clint_clear_ipi();
 #endif
 

-- 
2.43.0

[PATCH v2 4/6] irqchip/aclint-sswi: Use IPI_MAX for IPI muxing

[GUO Ren (XuanTie)]

Replace the hard-coded BITS_PER_BYTE with IPI_MAX now that the constant
is exported from riscv asm/smp.h.

Signed-off-by: GUO Ren (XuanTie) <guoren@kernel.org>
---
 drivers/irqchip/irq-aclint-sswi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-aclint-sswi.c b/drivers/irqchip/irq-aclint-sswi.c
index ca06efd86fa1..5e010fc401f7 100644
--- a/drivers/irqchip/irq-aclint-sswi.c
+++ b/drivers/irqchip/irq-aclint-sswi.c
@@ -138,7 +138,7 @@ static int __init aclint_sswi_probe(struct fwnode_handle *fwnode)
 	}
 
 	/* Register SSWI irq and handler */
-	virq = ipi_mux_create(BITS_PER_BYTE, aclint_sswi_ipi_send);
+	virq = ipi_mux_create(IPI_MAX, aclint_sswi_ipi_send);
 	if (virq <= 0) {
 		pr_err("unable to create muxed IPIs\n");
 		irq_dispose_mapping(sswi_ipi_virq);
@@ -152,7 +152,7 @@ static int __init aclint_sswi_probe(struct fwnode_handle *fwnode)
 			  aclint_sswi_starting_cpu,
 			  aclint_sswi_dying_cpu);
 
-	riscv_ipi_set_virq_range(virq, BITS_PER_BYTE);
+	riscv_ipi_set_virq_range(virq, IPI_MAX);
 
 	return 0;
 }

-- 
2.43.0

[PATCH v2 5/6] irqchip/imsic: Use IPI_MAX instead of IMSIC_NR_IPI

[GUO Ren (XuanTie)]

IMSIC was defining its own IMSIC_NR_IPI (= 8) which happened to match
the architecture's IPI_MAX. Now that IPI_MAX is exported from riscv
asm/smp.h, use the architecture constant and drop the private define.

This keeps the number of multiplexed IPIs in sync with the rest of the
RISC-V IPI infrastructure.

Signed-off-by: GUO Ren (XuanTie) <guoren@kernel.org>
---
 drivers/irqchip/irq-riscv-imsic-early.c | 4 ++--
 drivers/irqchip/irq-riscv-imsic-state.h | 1 -
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-riscv-imsic-early.c b/drivers/irqchip/irq-riscv-imsic-early.c
index 12efd241ce88..823f5f2ecb3d 100644
--- a/drivers/irqchip/irq-riscv-imsic-early.c
+++ b/drivers/irqchip/irq-riscv-imsic-early.c
@@ -67,12 +67,12 @@ static int __init imsic_ipi_domain_init(void)
 		return 0;
 
 	/* Create IMSIC IPI multiplexing */
-	virq = ipi_mux_create(IMSIC_NR_IPI, imsic_ipi_send);
+	virq = ipi_mux_create(IPI_MAX, imsic_ipi_send);
 	if (virq <= 0)
 		return virq < 0 ? virq : -ENOMEM;
 
 	/* Set vIRQ range */
-	riscv_ipi_set_virq_range(virq, IMSIC_NR_IPI);
+	riscv_ipi_set_virq_range(virq, IPI_MAX);
 
 	/* Announce that IMSIC is providing IPIs */
 	pr_info("%pfwP: providing IPIs using interrupt %d\n", imsic->fwnode, IMSIC_IPI_ID);
diff --git a/drivers/irqchip/irq-riscv-imsic-state.h b/drivers/irqchip/irq-riscv-imsic-state.h
index c42ee180b305..878cc192ccec 100644
--- a/drivers/irqchip/irq-riscv-imsic-state.h
+++ b/drivers/irqchip/irq-riscv-imsic-state.h
@@ -13,7 +13,6 @@
 #include <linux/timer.h>
 
 #define IMSIC_IPI_ID				1
-#define IMSIC_NR_IPI				8
 
 struct imsic_vector {
 	/* Fixed details of the vector */

-- 
2.43.0

[PATCH v2 6/6] media: mtk-vpu: rename IPI_MAX to IPI_VPU_MAX

[GUO Ren (XuanTie)]

The last enumerator of this driver's firmware IPI id list is a bound
for the VPU mailbox protocol, not a generic host IPI limit. Follow the
existing naming in this header: IPI_VPU_INIT already carries a VPU
prefix, so the terminator should match.

The same convention is used by the SCP IPI enum, which ends with a
prefixed SCP_IPI_MAX rather than a bare IPI_MAX.

Rename IPI_MAX to IPI_VPU_MAX and update the descriptor table bounds
and range checks. No functional change.

Link: https://lore.kernel.org/linux-riscv/20260908222349.GA2324870@ax162
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: GUO Ren (XuanTie) <guoren@kernel.org>
---
 drivers/media/platform/mediatek/vpu/mtk_vpu.c | 12 ++++++------
 drivers/media/platform/mediatek/vpu/mtk_vpu.h |  4 ++--
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/media/platform/mediatek/vpu/mtk_vpu.c b/drivers/media/platform/mediatek/vpu/mtk_vpu.c
index 8d8319f0cd22..b3e9f8c4ab7a 100644
--- a/drivers/media/platform/mediatek/vpu/mtk_vpu.c
+++ b/drivers/media/platform/mediatek/vpu/mtk_vpu.c
@@ -211,7 +211,7 @@ struct mtk_vpu {
 	struct vpu_regs reg;
 	struct vpu_run run;
 	struct vpu_wdt wdt;
-	struct vpu_ipi_desc ipi_desc[IPI_MAX];
+	struct vpu_ipi_desc ipi_desc[IPI_VPU_MAX];
 	struct share_obj __iomem *recv_buf;
 	struct share_obj __iomem *send_buf;
 	struct device *dev;
@@ -221,7 +221,7 @@ struct mtk_vpu {
 	struct mutex vpu_mutex; /* for protecting vpu data data structure */
 	u32 wdt_refcnt;
 	wait_queue_head_t ack_wq;
-	bool ipi_id_ack[IPI_MAX];
+	bool ipi_id_ack[IPI_VPU_MAX];
 };
 
 static inline void vpu_cfg_writel(struct mtk_vpu *vpu, u32 val, u32 offset)
@@ -296,7 +296,7 @@ int vpu_ipi_register(struct platform_device *pdev,
 		return -EPROBE_DEFER;
 	}
 
-	if (id < IPI_MAX && handler) {
+	if (id < IPI_VPU_MAX && handler) {
 		ipi_desc = vpu->ipi_desc;
 		ipi_desc[id].name = name;
 		ipi_desc[id].handler = handler;
@@ -319,7 +319,7 @@ int vpu_ipi_send(struct platform_device *pdev,
 	unsigned long timeout;
 	int ret = 0;
 
-	if (id <= IPI_VPU_INIT || id >= IPI_MAX ||
+	if (id <= IPI_VPU_INIT || id >= IPI_VPU_MAX ||
 	    len > sizeof(send_obj->share_buf) || !buf) {
 		dev_err(vpu->dev, "failed to send ipi message\n");
 		return -EINVAL;
@@ -748,7 +748,7 @@ static void vpu_ipi_handler(struct mtk_vpu *vpu)
 	s32 id = readl(&rcv_obj->id);
 
 	memcpy_fromio(data, rcv_obj->share_buf, sizeof(data));
-	if (id < IPI_MAX && ipi_desc[id].handler) {
+	if (id < IPI_VPU_MAX && ipi_desc[id].handler) {
 		ipi_desc[id].handler(data, readl(&rcv_obj->len),
 				     ipi_desc[id].priv);
 		if (id > IPI_VPU_INIT) {
@@ -934,7 +934,7 @@ static int mtk_vpu_probe(struct platform_device *pdev)
 #ifdef CONFIG_DEBUG_FS
 	debugfs_remove(vpu_debugfs);
 #endif
-	memset(vpu->ipi_desc, 0, sizeof(struct vpu_ipi_desc) * IPI_MAX);
+	memset(vpu->ipi_desc, 0, sizeof(struct vpu_ipi_desc) * IPI_VPU_MAX);
 vpu_mutex_destroy:
 	mutex_destroy(&vpu->vpu_mutex);
 disable_vpu_clk:
diff --git a/drivers/media/platform/mediatek/vpu/mtk_vpu.h b/drivers/media/platform/mediatek/vpu/mtk_vpu.h
index 3951547e9ec5..44ab631ec904 100644
--- a/drivers/media/platform/mediatek/vpu/mtk_vpu.h
+++ b/drivers/media/platform/mediatek/vpu/mtk_vpu.h
@@ -49,7 +49,7 @@ typedef void (*ipi_handler_t) (void *data,
  *			 handle VP8 video encoder job,, and vice versa.
  * @IPI_MDP:		 The interrupt from vpu is to notify kernel to
  *			 handle MDP (Media Data Path) job, and vice versa.
- * @IPI_MAX:		 The maximum IPI number
+ * @IPI_VPU_MAX:	 The maximum VPU IPI number
  */
 
 enum ipi_id {
@@ -60,7 +60,7 @@ enum ipi_id {
 	IPI_VENC_H264,
 	IPI_VENC_VP8,
 	IPI_MDP,
-	IPI_MAX,
+	IPI_VPU_MAX,
 };
 
 /**

-- 
2.43.0