hw/riscv/riscv-iommu: add riscv-iommu-hpm file

The HPM (Hardware Performance Monitor) support consists of almost 7
hundred lines that would be put on top of the base riscv-iommu
emulation.

To avoid clogging riscv-iommu.c, add a separated riscv-iommu-hpm file
that will contain HPM specific code.

We'll start by adding riscv_iommu_hpmcycle_read(), a helper that will be
called during the riscv_iommu_mmio_read() callback.

This change will have no effect on the existing emulation since we're
not declaring HPM feature support.

Signed-off-by: Tomasz Jeznach <tjeznach@rivosinc.com>
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20250224190826.1858473-4-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

hw/riscv/riscv-iommu-hpm.h

@@ -0,0 +1,27 @@
+/*
+ * RISC-V IOMMU - Hardware Performance Monitor (HPM) helpers
+ *
+ * Copyright (C) 2022-2023 Rivos Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef HW_RISCV_IOMMU_HPM_H
+#define HW_RISCV_IOMMU_HPM_H
+
+#include "qom/object.h"
+#include "hw/riscv/riscv-iommu.h"
+
+uint64_t riscv_iommu_hpmcycle_read(RISCVIOMMUState *s);
+
+#endif