[PATCH v11 2/2] iommu/riscv: create a auxiliary device for HPM
From: Zong Li <hidden>
Date: 2026-09-14 03:57:30
Also in:
linux-iommu, linux-riscv, lkml
Subsystem:
iommu subsystem, risc-v iommu, the rest · Maintainers:
Joerg Roedel, Will Deacon, Tomasz Jeznach, Linus Torvalds
Create an auxiliary device for HPM when the IOMMU supports a hardware performance monitor. Tested-by: Chen Pei <redacted> Tested-by: Fangyu Yu <redacted> Reviewed-by: Nutty Liu <redacted> Reviewed-by: Guo Ren <guoren@kernel.org> Reviewed-by: Yicong Yang <redacted> Suggested-by: Samuel Holland <samuel.holland@sifive.com> Signed-off-by: Zong Li <redacted> --- drivers/iommu/riscv/Kconfig | 1 + drivers/iommu/riscv/iommu.c | 37 +++++++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+)
diff --git a/drivers/iommu/riscv/Kconfig b/drivers/iommu/riscv/Kconfig
index b86e5ab94183..8025bf0fb67f 100644
--- a/drivers/iommu/riscv/Kconfig
+++ b/drivers/iommu/riscv/Kconfig@@ -10,6 +10,7 @@ config RISCV_IOMMU select GENERIC_PT select IOMMU_PT select IOMMU_PT_RISCV64 + select AUXILIARY_BUS help Support for implementations of the RISC-V IOMMU architecture that complements the RISC-V MMU capabilities, providing similar address
diff --git a/drivers/iommu/riscv/iommu.c b/drivers/iommu/riscv/iommu.c
index fe8e6d0f8a23..c7495cc57720 100644
--- a/drivers/iommu/riscv/iommu.c
+++ b/drivers/iommu/riscv/iommu.c@@ -14,6 +14,7 @@ #include <linux/acpi.h> #include <linux/acpi_rimt.h> +#include <linux/auxiliary_bus.h> #include <linux/compiler.h> #include <linux/crash_dump.h> #include <linux/init.h>
@@ -48,6 +49,9 @@ static DEFINE_IDA(riscv_iommu_pscids); #define RISCV_IOMMU_MAX_PSCID (BIT(20) - 1) +/* IOMMU PMU auxiliary device id allocation namespace. */ +static DEFINE_IDA(riscv_iommu_pmu_ida); + /* Device resource-managed allocations */ struct riscv_iommu_devres { void *addr;
@@ -587,6 +591,36 @@ static irqreturn_t riscv_iommu_fltq_process(int irq, void *data) return IRQ_HANDLED; } +/* + * IOMMU Hardware performance monitor + */ +static void riscv_iommu_pmu_id_free(void *data) +{ + ida_free(&riscv_iommu_pmu_ida, (unsigned long)data); +} + +static int riscv_iommu_hpm_enable(struct riscv_iommu_device *iommu) +{ + struct auxiliary_device *auxdev; + int id, ret; + + id = ida_alloc(&riscv_iommu_pmu_ida, GFP_KERNEL); + if (id < 0) + return id; + + ret = devm_add_action_or_reset(iommu->dev, riscv_iommu_pmu_id_free, + (void *)(unsigned long)id); + if (ret) + return ret; + + auxdev = __devm_auxiliary_device_create(iommu->dev, "riscv-iommu", + "pmu", iommu, id); + if (!auxdev) + return -ENODEV; + + return 0; +} + /* Lookup and initialize device context info structure. */ static struct riscv_iommu_dc *riscv_iommu_get_dc(struct riscv_iommu_device *iommu, unsigned int devid)
@@ -1636,6 +1670,9 @@ int riscv_iommu_init(struct riscv_iommu_device *iommu) goto err_remove_sysfs; } + if (iommu->caps & RISCV_IOMMU_CAPABILITIES_HPM) + riscv_iommu_hpm_enable(iommu); + return 0; err_remove_sysfs:
--
2.43.7