Re: [igt-dev] [PATCH i-g-t v3 5/5] tests/device_reset: Add cold reset IGT test

["Iddamsetty, Aravind" <aravind.iddamsetty@intel.com>]

On 23-11-2022 14:24, Anshuman Gupta wrote:
> Add cold-reset IGT subtest, IGT subtest will use
> /sys/bus/pci/slots/$SUN/power sysfs in order to
> initiate a cold reset sequence. $SUN value will be
> retrieved from PCIe device ACPI firmware node.
> 
> v2:
> - %s/igt_require(fd > 0)/igt_assert(errno >0)
> v3:
> - Added Slot Power Controller capability check. [Aravind]
> - Check whether slot is powered down before powering up. [Aravind]
> 
> Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
> Reviewed-by: Badal Nilawar <badal.nilawar@intel.com>
> ---
>  lib/igt_pm.c         |  40 +++++++++++
>  lib/igt_pm.h         |   1 +
>  tests/device_reset.c | 153 ++++++++++++++++++++++++++++++++++++++++---
>  3 files changed, 184 insertions(+), 10 deletions(-)
> 
> diff --git a/lib/igt_pm.c b/lib/igt_pm.c
> index 4f0cfbdd10..9b7ed4be64 100644
> --- a/lib/igt_pm.c
> +++ b/lib/igt_pm.c
> @@ -877,6 +877,46 @@ static int igt_pm_open_pci_firmware_node(struct pci_device *pci_dev)
>  	return dir;
>  }
>  
> +/**
> + * igt_pm_get_pcie_acpihp_slot:
> + * @pci_dev: pci bridge device.
> + * Get pci bridge acpi hotplug slot number, if bridge's ACPI firmware_node
> + * handle supports _SUN method.
> + *
> + * Returns:
> + * PCIe bridge Slot number.
> + * Returns -ENOENT number in case firmware_node/sun is not supported by the
> + * bridge.
> + */
> +int igt_pm_get_pcie_acpihp_slot(struct pci_device *pci_dev)
> +{
> +	int firmware_node_fd, fd, n_read;
> +	char sun[8];
> +
> +	firmware_node_fd = igt_pm_open_pci_firmware_node(pci_dev);
> +
> +	if (firmware_node_fd < 0 && errno == ENOENT)
> +		return -ENOENT;
> +
> +	igt_require(firmware_node_fd > 0);
> +
> +	fd = openat(firmware_node_fd, "sun", O_RDONLY);
> +	if (fd < 0 && errno == ENOENT) {
> +		close(firmware_node_fd);
> +		return -ENOENT;
> +	}
> +
> +	igt_assert(errno > 0);
> +
> +	n_read = read(fd, sun, sizeof(sun));
> +	igt_assert(n_read > 0);
> +
> +	close(firmware_node_fd);
> +	close(fd);
> +
> +	return strtol(sun, NULL, 10);
> +}
> +
>  /**
>   * igt_pm_acpi_d3cold_supported:
>   * @pci_dev: root port pci_dev.
> diff --git a/lib/igt_pm.h b/lib/igt_pm.h
> index e81fceb897..f65b960c38 100644
> --- a/lib/igt_pm.h
> +++ b/lib/igt_pm.h
> @@ -73,6 +73,7 @@ bool igt_wait_for_pm_status(enum igt_runtime_pm_status status);
>  bool igt_pm_dmc_loaded(int debugfs);
>  bool igt_pm_pc8_plus_residencies_enabled(int msr_fd);
>  bool i915_output_is_lpsp_capable(int drm_fd, igt_output_t *output);
> +int igt_pm_get_pcie_acpihp_slot(struct pci_device *pci_dev);
>  bool igt_pm_acpi_d3cold_supported(struct pci_device *pci_dev);
>  enum igt_acpi_d_state
>  igt_pm_get_acpi_real_d_state(struct pci_device *pci_dev);
> diff --git a/tests/device_reset.c b/tests/device_reset.c
> index 0c477a02c0..4c624ce7d3 100644
> --- a/tests/device_reset.c
> +++ b/tests/device_reset.c
> @@ -9,7 +9,9 @@
>  
>  #include "i915/gem.h"
>  #include "igt.h"
> +#include "igt_device.h"
>  #include "igt_device_scan.h"
> +#include "igt_pci.h"
>  #include "igt_sysfs.h"
>  #include "igt_kmod.h"
>  
> @@ -33,6 +35,7 @@ struct device_fds {
>  		int dev;
>  		int dev_dir;
>  		int drv_dir;
> +		int slot_dir; /* pci hotplug slots fd */
>  	} fds;
>  	char dev_bus_addr[DEV_BUS_ADDR_LEN];
>  	bool snd_unload;
> @@ -62,6 +65,45 @@ static int open_driver_sysfs_dir(int fd)
>  	return __open_sysfs_dir(fd, "device/driver");
>  }
>  
> +static int open_slot_sysfs_dir(int fd)
> +{
> +	struct pci_device *pci_dev = NULL;
> +	int slot_fd = -1, slot;
> +	char slot_fd_path[PATH_MAX];
> +
> +	pci_dev = igt_device_get_pci_device(fd);
> +	igt_require(pci_dev);
> +
> +	while ((pci_dev = pci_device_get_parent_bridge(pci_dev))) {
> +		slot = igt_pm_get_pcie_acpihp_slot(pci_dev);
> +		if (slot == -ENOENT) {
> +			igt_debug("Bridge PCI device %04x:%02x:%02x.%01x does not support acpihp slot\n",
> +				  pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func);
> +			continue;
> +		}
> +
> +		/*
> +		 * Upon getting the valid acpihp slot number break the loop.
> +		 * It is the desired acpihp slot for gfx card.
> +		 */
> +		if (slot > 0) {
> +			igt_debug("Bridge PCI device %04x:%02x:%02x.%01x associated acpihp slot %d\n",
> +				  pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func, slot);
> +			break;
> +		}
> +	}
> +
> +	if (!pci_dev)
> +		return slot_fd;
> +
> +	snprintf(slot_fd_path, PATH_MAX, "/sys/bus/pci/slots/%d", slot);
> +	slot_fd = open(slot_fd_path, O_RDONLY);
> +	if (slot_fd < 0)
> +		return -errno;
> +
> +	return slot_fd;
> +}
> +
>  /**
>   * device_sysfs_path:
>   * @fd: opened device file descriptor
> @@ -124,6 +166,8 @@ static void init_device_fds(struct device_fds *dev)
>  
>  	dev->fds.drv_dir = open_driver_sysfs_dir(dev->fds.dev);
>  	igt_assert_fd(dev->fds.drv_dir);
> +
> +	dev->fds.slot_dir = open_slot_sysfs_dir(dev->fds.dev);
>  }
>  
>  static int close_if_opened(int *fd)
> @@ -142,6 +186,7 @@ static void cleanup_device_fds(struct device_fds *dev)
>  	igt_ignore_warn(close_if_opened(&dev->fds.dev));
>  	igt_ignore_warn(close_if_opened(&dev->fds.dev_dir));
>  	igt_ignore_warn(close_if_opened(&dev->fds.drv_dir));
> +	igt_ignore_warn(close_if_opened(&dev->fds.slot_dir));
>  }
>  
>  /**
> @@ -179,6 +224,60 @@ static bool is_sysfs_reset_supported(int fd)
>  	return true;
>  }
>  
> +/**
> + * is_sysfs_cold_reset_supported:
> + * @fd: opened device file descriptor
> + *
> + * Check if device supports cold reset based on sysfs file presence.
> + *
> + * Returns:
> + * True if device supports reset, false otherwise.
> + */
> +static bool is_sysfs_cold_reset_supported(int slot_fd)
> +{
> +	struct stat st;
> +	int rc;
> +	int cold_reset_fd = -1;
> +
> +	cold_reset_fd = openat(slot_fd, "power", O_WRONLY);
> +
> +	if (cold_reset_fd < 0)
> +		return false;
> +
> +	rc = fstat(cold_reset_fd, &st);
> +	close(cold_reset_fd);
> +
> +	if (rc || !S_ISREG(st.st_mode))
> +		return false;
> +
> +	return true;
> +}
> +

why do not you combine the below two checks into
is_sysfs_cold_reset_supported as the check will be done only if power
sysfs is present.

Thanks,
Aravind.
> +static bool is_pci_power_ctrl_present(struct pci_device *dev)
> +{
> +	int offset;
> +	uint32_t slot_cap;
> +
> +	offset = find_pci_cap_offset(dev, PCI_EXPRESS_CAP_ID);
> +	igt_require_f(offset > 0, "PCI Express Capability not found\n");
> +	igt_assert(!pci_device_cfg_read_u32(dev, &slot_cap, offset + PCI_SLOT_CAP_OFFSET));
> +	igt_debug("slot cap register 0x%x\n", slot_cap);
> +
> +	return slot_cap & PCI_SLOT_PWR_CTRL_PRESENT;
> +}
> +
> +static bool is_slot_power_ctrl_present(int fd)
> +{
> +	struct pci_device *root;
> +
> +	/*
> +	 * Card root port Slot Capabilities Register
> +	 * determines Power Controller Presence.
> +	 */
> +	root = igt_device_get_pci_root_port(fd);
> +	return is_pci_power_ctrl_present(root);
> +}
> +
>  /* Unbind the driver from the device */
>  static void driver_unbind(struct device_fds *dev)
>  {
> @@ -231,8 +330,13 @@ static void initiate_device_reset(struct device_fds *dev, enum reset type)
>  {
>  	igt_debug("reset device\n");
>  
> -	if (type == FLR_RESET)
> +	if (type == FLR_RESET) {
>  		igt_assert(igt_sysfs_set(dev->fds.dev_dir, "reset", "1"));
> +	} else if (type == COLD_RESET) {
> +		igt_assert(igt_sysfs_set(dev->fds.slot_dir, "power", "0"));
> +		igt_assert(!igt_sysfs_get_boolean(dev->fds.slot_dir, "power"));
> +		igt_assert(igt_sysfs_set(dev->fds.slot_dir, "power", "1"));
> +	}
>  
>  }
>  
> @@ -311,17 +415,46 @@ igt_main
>  		igt_skip_on(!is_sysfs_reset_supported(dev.fds.dev));
>  	}
>  
> -	igt_describe("Unbinds driver from device, initiates reset"
> -		     " then rebinds driver to device");
> -	igt_subtest("unbind-reset-rebind") {
> -		unbind_reset_rebind(&dev, FLR_RESET);
> -		healthcheck(&dev);
> +	igt_subtest_group {
> +		igt_describe("Unbinds driver from device, initiates reset"
> +			     " then rebinds driver to device");
> +		igt_subtest("unbind-reset-rebind") {
> +			unbind_reset_rebind(&dev, FLR_RESET);
> +			healthcheck(&dev);
> +		}
> +
> +		igt_describe("Resets device with bound driver");
> +		igt_subtest("reset-bound") {
> +			initiate_device_reset(&dev, FLR_RESET);
> +			/*
> +			 * Cold reset will initiate card boot sequence again,
> +			 * therefore let healthcheck() re-epen the dev fd.
> +			 */
> +			dev.fds.dev = -1;
> +			healthcheck(&dev);
> +		}
>  	}
>  
> -	igt_describe("Resets device with bound driver");
> -	igt_subtest("reset-bound") {
> -		initiate_device_reset(&dev, FLR_RESET);
> -		healthcheck(&dev);
> +	igt_subtest_group {
> +		igt_fixture {
> +			igt_skip_on_f(dev.fds.slot_dir < 0, "Gfx Card does not support any "
> +				      "pcie slot for cold reset\n");
> +			igt_skip_on(!is_sysfs_cold_reset_supported(dev.fds.slot_dir));
> +			igt_skip_on(!is_slot_power_ctrl_present(dev.fds.dev));
> +		}
> +
> +		igt_describe("Unbinds driver from device, initiates cold reset"
> +			     " then rebinds driver to device");
> +		igt_subtest("unbind-cold-reset-rebind") {
> +			unbind_reset_rebind(&dev, COLD_RESET);
> +			healthcheck(&dev);
> +		}
> +
> +		igt_describe("Cold Resets device with bound driver");
> +		igt_subtest("cold-reset-bound") {
> +			initiate_device_reset(&dev, COLD_RESET);
> +			healthcheck(&dev);
> +		}
>  	}
>  
>  	igt_fixture {