misc: mods: add IPI ioctls

* Added ioctl for triggering IPIs
 * Added handler to invoke ASM wfe,wfi commands or NOP

Change-Id: I907b6a27f3a7f3ff5b507e9f91066d8695dadbb4
Signed-off-by: Ian Grissom <igrissom@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvidia/+/2730675
Reviewed-by: Chris Dragan <kdragan@nvidia.com>
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>
GVS: Gerrit_Virtual_Submit <buildbot_gerritrpt@nvidia.com>

drivers/misc/mods/Makefile

@@ -18,6 +18,7 @@ mods-$(CONFIG_TEGRA_NVADSP)        += mods_adsp.o
 mods-$(CONFIG_COMMON_CLK)          += mods_clock.o
 mods-$(CONFIG_DEBUG_FS)            += mods_debugfs.o
 mods-$(CONFIG_DMA_ENGINE)          += mods_dma.o
+mods-$(CONFIG_ARCH_TEGRA)          += mods_ipi.o
 mods-$(CONFIG_NET)                 += mods_netdevice.o
 mods-$(CONFIG_ARCH_TEGRA)          += mods_oist.o
 mods-$(CONFIG_OPTEE)               += mods_optee.o

drivers/misc/mods/mods_internal.h

@@ -739,4 +739,8 @@ int smmu_driver_init(void);
 void smmu_driver_exit(void);
 #endif
 
+#if defined(MODS_HAS_TEGRA)
+int esc_mods_send_ipi(struct mods_client *client, struct MODS_SEND_IPI *p);
+#endif
+
 #endif	/* _MODS_INTERNAL_H_  */

drivers/misc/mods/mods_ipi.c

@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file is part of NVIDIA MODS kernel driver.
+ *
+ * Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved.
+ *
+ * NVIDIA MODS kernel driver is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * NVIDIA MODS kernel driver 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 NVIDIA MODS kernel driver.
+ * If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "mods_internal.h"
+
+#include <asm/barrier.h>
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+#include <linux/slab.h>
+#include <linux/smp.h>
+
+#define MAX_IPI_WFI_LOOPS	5
+#define MAX_IPI_WFE_LOOPS	10
+
+static void ipi_wfi_cpu(void *p)
+{
+	struct MODS_SEND_IPI *p_ipi = (struct MODS_SEND_IPI *)p;
+	u32 i;
+
+	for (i = 0; i < p_ipi->num_loops; i++)
+		wfi();
+}
+
+static void ipi_wfe_cpu(void *p)
+{
+	struct MODS_SEND_IPI *p_ipi = (struct MODS_SEND_IPI *)p;
+	u32 i;
+
+	for (i = 0; i < p_ipi->num_loops; i++)
+		wfe();
+}
+
+int esc_mods_send_ipi(struct mods_client *client, struct MODS_SEND_IPI *p)
+{
+	LOG_ENT();
+
+	switch (p->ipi_type) {
+	case MODS_IPI_KICK: {
+		kick_all_cpus_sync();
+		break;
+	}
+	case MODS_IPI_WFI: {
+		if (p->num_loops > MAX_IPI_WFI_LOOPS) {
+			cl_error("num_loops %u exceed maximum limit %d for MODS_IPI_WFI\n",
+				p->num_loops,
+				MAX_IPI_WFI_LOOPS);
+			LOG_EXT();
+			return -EINVAL;
+		}
+		preempt_disable();
+		smp_call_function_many(cpu_online_mask, ipi_wfi_cpu, (void *)p, 1);
+		preempt_enable();
+		break;
+	}
+	case MODS_IPI_WFE: {
+		if (p->num_loops > MAX_IPI_WFE_LOOPS) {
+			cl_error("num_loops %u exceed maximum limit %d for MODS_IPI_WFE\n",
+				p->num_loops,
+				MAX_IPI_WFE_LOOPS);
+			LOG_EXT();
+			return -EINVAL;
+		}
+		preempt_disable();
+		smp_call_function_many(cpu_online_mask, ipi_wfe_cpu, (void *)p, 1);
+		preempt_enable();
+		break;
+	}
+	default: {
+		cl_error("unsupported MODS_IPI_TYPE\n");
+		LOG_EXT();
+		return -EINVAL;
+	}
+	}
+
+	LOG_EXT();
+	return 0;
+}

drivers/misc/mods/mods_krnl.c

@@ -2604,6 +2604,11 @@ static long mods_krnl_ioctl(struct file  *fp,
 		MODS_IOCTL(MODS_ESC_OIST_STATUS,
 			   esc_mods_oist_status, MODS_TEGRA_OIST_STATUS);
 		break;
+
+	case MODS_ESC_MODS_SEND_IPI:
+		MODS_IOCTL(MODS_ESC_MODS_SEND_IPI,
+			   esc_mods_send_ipi, MODS_SEND_IPI);
+		break;
 #endif
 
 	case MODS_ESC_ACQUIRE_ACCESS_TOKEN:

include/uapi/misc/mods.h

@@ -1858,6 +1858,23 @@ struct MODS_TEGRA_OIST_STATUS {
 	__u64 smc_status;
 };
 
+enum MODS_IPI_TYPE {
+	MODS_IPI_KICK,
+	MODS_IPI_WFI,
+	MODS_IPI_WFE
+};
+
+/* Used by MODS_ESC_MODS_SEND_IPI ioctl.
+ *
+ * Available only on Tegra.
+ */
+struct MODS_SEND_IPI {
+	/* IN */
+	__u32 ipi_type;
+	/* IN */
+	__u32 num_loops;
+};
+
 #define MODS_IOMMU_MAP_CONTIGUOUS 1
 
 #define MODS_MAX_PROP_NAME_LEN 64
@@ -2097,5 +2114,6 @@ struct MODS_PROXIMITY_TO_NUMA_NODE {
 #define MODS_ESC_INVOKE_OPTEE_TA MODSIO(WR, 141, MODS_OPTEE_PARAMS)
 #define MODS_ESC_READ_DEV_PROPERTY MODSIO(WR, 142, MODS_READ_DEV_PROPERTY)
 #define MODS_ESC_PROXIMITY_TO_NUMA_NODE MODSIO(WR, 143, MODS_PROXIMITY_TO_NUMA_NODE)
+#define MODS_ESC_MODS_SEND_IPI MODSIO(W, 144, MODS_SEND_IPI)
 
 #endif /* _UAPI_MODS_H_  */