iio: proximity: vl53l0x-i2c: claim direct mode for raw readsgrafted

vl53l0x_read_raw() starts a single-shot ranging measurement and reads
back the result. Once the triggered buffer is enabled the sensor runs in
continuous mode and its data-ready interrupt is routed to the trigger,
so a concurrent in_distance_raw read disturbs the streaming setup and
never gets its completion, returning -ETIMEDOUT.

The original submission claimed direct mode here, but it was dropped
during review because the driver had no buffer support at the time [1].
Continuous (buffered) mode was later added without restoring the
claim [2], reintroducing the conflict.

Reject direct reads while buffered capture is active by claiming direct
mode around the measurement, as the vl53l1x sibling already does.

Fixes: 762186c6e7b1 ("iio: proximity: vl53l0x-i2c: Added continuous mode support")
Link: https://lore.kernel.org/linux-iio/20180911160300.GA9212@himanshu-Vostro-3559/ [1]
Link: https://lore.kernel.org/linux-iio/20240909101508.263085-3-abhashkumarjha123@gmail.com/ [2]
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

1 files changed, 132 insertions, 0 deletions

diff --git a/samples/acrn/vm-sample.c b/samples/acrn/vm-sample.c
new file mode 100644
index 000000000..c61e0f914
--- /dev/null
+++ b/samples/acrn/vm-sample.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * A sample program to run a User VM on the ACRN hypervisor
+ *
+ * This sample runs in a Service VM, which is a privileged VM of ACRN.
+ * CONFIG_ACRN_HSM needs to be enabled in the Service VM.
+ *
+ * Guest VM code in guest16.s will be executed after the VM launched.
+ *
+ * Copyright (C) 2020 Intel Corporation. All rights reserved.
+ */
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <signal.h>
+#include <sys/ioctl.h>
+#include <linux/acrn.h>
+
+#define GUEST_MEMORY_SIZE	(1024*1024)
+void *guest_memory;
+
+extern const unsigned char guest16[], guest16_end[];
+static char io_request_page[4096] __attribute__((aligned(4096)));
+static struct acrn_io_request *io_req_buf = (struct acrn_io_request *)io_request_page;
+
+__u16 vcpu_num;
+__u16 vmid;
+
+int hsm_fd;
+int is_running = 1;
+
+void vm_exit(int sig)
+{
+	sig = sig;
+
+	is_running = 0;
+	ioctl(hsm_fd, ACRN_IOCTL_PAUSE_VM, vmid);
+	ioctl(hsm_fd, ACRN_IOCTL_DESTROY_IOREQ_CLIENT, 0);
+}
+
+int main(int argc, char **argv)
+{
+	int vcpu_id, ret;
+	struct acrn_vm_creation create_vm = {0};
+	struct acrn_vm_memmap ram_map = {0};
+	struct acrn_vcpu_regs regs;
+	struct acrn_io_request *io_req;
+	struct acrn_ioreq_notify __attribute__((aligned(8))) notify;
+
+	argc = argc;
+	argv = argv;
+
+	ret = posix_memalign(&guest_memory, 4096, GUEST_MEMORY_SIZE);
+	if (ret < 0) {
+		printf("Not enough memory!\n");
+		return -1;
+	}
+	hsm_fd = open("/dev/acrn_hsm", O_RDWR|O_CLOEXEC);
+
+	create_vm.ioreq_buf = (__u64)io_req_buf;
+	ret = ioctl(hsm_fd, ACRN_IOCTL_CREATE_VM, &create_vm);
+	printf("Created VM! [%d]\n", ret);
+	vcpu_num = create_vm.vcpu_num;
+	vmid = create_vm.vmid;
+
+	/* setup guest memory */
+	ram_map.type = ACRN_MEMMAP_RAM;
+	ram_map.vma_base = (__u64)guest_memory;
+	ram_map.len = GUEST_MEMORY_SIZE;
+	ram_map.user_vm_pa = 0;
+	ram_map.attr = ACRN_MEM_ACCESS_RWX;
+	ret = ioctl(hsm_fd, ACRN_IOCTL_SET_MEMSEG, &ram_map);
+	printf("Set up VM memory! [%d]\n", ret);
+
+	memcpy(guest_memory, guest16, guest16_end-guest16);
+
+	/* setup vcpu registers */
+	memset(&regs, 0, sizeof(regs));
+	regs.vcpu_id = 0;
+	regs.vcpu_regs.rip = 0;
+
+	/* CR0_ET | CR0_NE */
+	regs.vcpu_regs.cr0 = 0x30U;
+	regs.vcpu_regs.cs_ar = 0x009FU;
+	regs.vcpu_regs.cs_sel = 0xF000U;
+	regs.vcpu_regs.cs_limit = 0xFFFFU;
+	regs.vcpu_regs.cs_base = 0 & 0xFFFF0000UL;
+	regs.vcpu_regs.rip = 0 & 0xFFFFUL;
+
+	ret = ioctl(hsm_fd, ACRN_IOCTL_SET_VCPU_REGS, &regs);
+	printf("Set up VM BSP registers! [%d]\n", ret);
+
+	/* create an ioreq client for this VM */
+	ret = ioctl(hsm_fd, ACRN_IOCTL_CREATE_IOREQ_CLIENT, 0);
+	printf("Created IO request client! [%d]\n", ret);
+
+	/* run vm */
+	ret = ioctl(hsm_fd, ACRN_IOCTL_START_VM, vmid);
+	printf("Start VM! [%d]\n", ret);
+
+	signal(SIGINT, vm_exit);
+	while (is_running) {
+		ret = ioctl(hsm_fd, ACRN_IOCTL_ATTACH_IOREQ_CLIENT, 0);
+
+		for (vcpu_id = 0; vcpu_id < vcpu_num; vcpu_id++) {
+			io_req = &io_req_buf[vcpu_id];
+			if ((__sync_add_and_fetch(&io_req->processed, 0) == ACRN_IOREQ_STATE_PROCESSING)
+					&& (!io_req->kernel_handled))
+				if (io_req->type == ACRN_IOREQ_TYPE_PORTIO) {
+					int bytes, port, in;
+
+					port = io_req->reqs.pio_request.address;
+					bytes = io_req->reqs.pio_request.size;
+					in = (io_req->reqs.pio_request.direction == ACRN_IOREQ_DIR_READ);
+					printf("Guest VM %s PIO[%x] with size[%x]\n", in ? "read" : "write", port, bytes);
+
+					notify.vmid = vmid;
+					notify.vcpu = vcpu_id;
+					ioctl(hsm_fd, ACRN_IOCTL_NOTIFY_REQUEST_FINISH, &notify);
+				}
+		}
+	}
+
+	ret = ioctl(hsm_fd, ACRN_IOCTL_DESTROY_VM, NULL);
+	printf("Destroy VM! [%d]\n", ret);
+	close(hsm_fd);
+	free(guest_memory);
+	return 0;
+}