Re: [igt-dev] [PATCH i-g-t 3/9] lib/igt_pm: D3Cold runtime pm infrastructure

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Mon, Apr 18, 2022 at 06:20:42PM +0530, Anshuman Gupta wrote:
> Enable gfx card pci devices runtime pm for all pci devices
> and bridge under the topology of Gfx Card root port.
> 
> Added a library function to get the PCI root port ACPI
> D state and to print the pci card devices runtime pm
> status.
> 
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
> ---
>  lib/igt_pm.c | 226 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  lib/igt_pm.h |  21 +++++
>  2 files changed, 247 insertions(+)
> 
> diff --git a/lib/igt_pm.c b/lib/igt_pm.c
> index b409ec463..8e8a330f8 100644
> --- a/lib/igt_pm.c
> +++ b/lib/igt_pm.c
> @@ -28,6 +28,7 @@
>  #include <fcntl.h>
>  #include <stdio.h>
>  #include <limits.h>
> +#include <pciaccess.h>
>  #include <stdlib.h>
>  #include <string.h>
>  #include <unistd.h>
> @@ -75,6 +76,7 @@ enum {
>  #define MIN_POWER_STR		"min_power\n"
>  /* Remember to fix this if adding longer strings */
>  #define MAX_POLICY_STRLEN	strlen(MAX_PERFORMANCE_STR)
> +#define MAX_PCI_DEVICES		256
>  int8_t *__sata_pm_policies;
>  int __scsi_host_cnt;
>  
> @@ -856,3 +858,227 @@ bool i915_output_is_lpsp_capable(int drm_fd, igt_output_t *output)
>  
>  	return strstr(buf, "LPSP: capable");
>  }
> +
> +/**
> + * igt_pm_acpi_d3cold_suppoarted:

                              ^ typo

> + * @pci_dev: root port pci_dev.
> + * Check ACPI D3Cold support.
> + *
> + * Returns:
> + * True if ACPI D3Cold supported otherwise false.
> + */
> +bool igt_pm_acpi_d3cold_supported(struct pci_device *pci_dev)
> +{
> +	char name[PATH_MAX];
> +	int dir, fd;
> +
> +	snprintf(name, PATH_MAX,
> +		 "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/firmware_node",
> +		 pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func);
> +
> +	dir = open(name, O_RDONLY);
> +	igt_require(dir > 0);
> +
> +	/* BIOS need to enable ACPI D3Cold Support.*/
> +	fd = openat(dir, "real_power_state", O_RDONLY);
> +	if (fd < 0 && errno == ENOENT)
> +		return false;
> +
> +	igt_require(fd > 0);
> +
> +	return true;
> +}
> +
> +/**
> + * igt_pm_get_acpi_real_d_state:
> + * @pci_dev: root port pci_dev.
> + * Get ACPI D state for a given root port.
> + *
> + * Returns:
> + * igt_acpi_d_state state.
> + */
> +enum igt_acpi_d_state
> +igt_pm_get_acpi_real_d_state(struct pci_device *pci_dev)
> +{
> +	char name[PATH_MAX];
> +	char acpi_d_state[64];
> +	int fd, n_read;
> +
> +	snprintf(name, PATH_MAX,
> +		 "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/firmware_node/real_power_state",
> +		 pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func);
> +
> +	fd = open(name, O_RDONLY);
> +	if (fd < 0)
> +		return IGT_ACPI_UNKNOWN_STATE;
> +
> +	n_read = read(fd, acpi_d_state, sizeof(acpi_d_state) - 1);
> +	igt_assert(n_read >= 0);
> +	acpi_d_state[n_read] = '\0';
> +	close(fd);
> +
> +	if (strncmp(acpi_d_state, "D0\n", n_read) == 0)
> +		return IGT_ACPI_D0;
> +	else if  (strncmp(acpi_d_state, "D1\n", n_read) == 0)
> +		return IGT_ACPI_D1;
> +	else if  (strncmp(acpi_d_state, "D2\n", n_read) == 0)
> +		return IGT_ACPI_D2;
> +	else if  (strncmp(acpi_d_state, "D3hot\n", n_read) == 0)
> +		return IGT_ACPI_D3Hot;
> +	else if  (strncmp(acpi_d_state, "D3cold\n", n_read) == 0)
> +		return IGT_ACPI_D3Cold;
> +	else
> +		return IGT_ACPI_UNKNOWN_STATE;
> +}
> +
> +static struct igt_pm_pci_dev_control  __igt_pm_pci_control[MAX_PCI_DEVICES];

the only thing that I'm not totally comfortable with this patch is this global
struct of 256 items in a lib file.

Although I liked the use of the exit handler to restore the status...

> +
> +static void __igt_pm_pci_card_exit_handler(int sig)
> +{
> +	igt_pm_restore_pci_card_runtime_pm();
> +}
> +
> +static void
> +__igt_pm_setup_pci_card_runtime_pm(struct pci_device *pci_dev, int index)
> +{
> +	char name[PATH_MAX], buf[6];
> +	int fd, control_size, size;
> +	char *control;
> +
> +	igt_assert(index <  MAX_PCI_DEVICES);
> +
> +	control = __igt_pm_pci_control[index].control;
> +	control_size =  sizeof(__igt_pm_pci_control[index].control);
> +	__igt_pm_pci_control[index].pci_dev = pci_dev;
> +
> +	snprintf(name, PATH_MAX, "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/power/control",
> +		 pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func);
> +
> +	fd = open(name, O_RDWR);
> +	igt_assert_f(fd >= 0, "Can't open control\n");
> +
> +	igt_assert(read(fd, control, control_size - 1) > 0);
> +	strchomp(control);
> +
> +	igt_debug("Saved runtime power management for PCI '%04x:%02x:%02x.%01x' '%s'\n",
> +		  pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func, control);
> +	igt_install_exit_handler(__igt_pm_pci_card_exit_handler);
> +
> +	size = write(fd, "auto\n", 5);
> +	igt_assert(size == 5);
> +
> +	lseek(fd, 0, SEEK_SET);
> +	size = read(fd, buf, ARRAY_SIZE(buf));
> +	igt_assert(size == 5);
> +	igt_assert(strncmp(buf, "auto\n", 5) == 0);
> +
> +	close(fd);
> +}
> +
> +/**
> + * igt_pm_setup_pci_card_runtime_pm:
> + * @pci_dev: root port pci_dev.
> + * Setup runtime PM for all PCI endpoints devices for a given
> + * root port. It also save power control attribute for all PCI endpoints
> + * devices for a given root port.
> + */
> +void igt_pm_setup_pci_card_runtime_pm(struct pci_device *pci_dev)
> +{
> +	int primary, secondary, subordinate, ret;
> +	struct pci_device_iterator *iter;
> +	struct pci_device *dev;
> +	int i = 0;
> +
> +	memset(__igt_pm_pci_control, 0, sizeof(__igt_pm_pci_control));
> +	ret = pci_device_get_bridge_buses(pci_dev, &primary, &secondary, &subordinate);
> +	igt_assert(!ret);
> +
> +	ret = pci_system_init();
> +	igt_assert(!ret);
> +
> +	iter = pci_slot_match_iterator_create(NULL);
> +	/* Setup runtime pm for PCI root port */
> +	__igt_pm_setup_pci_card_runtime_pm(pci_dev, i++);
> +	while ((dev = pci_device_next(iter)) != NULL) {
> +		if (dev->bus >= secondary && dev->bus <= subordinate)
> +			__igt_pm_setup_pci_card_runtime_pm(dev, i++);
> +	}
> +}
> +
> +static void igt_pm_restore_pci_dev_runtime_pm(struct pci_device *pci_dev, char *control, int len)
> +{
> +	char name[PATH_MAX];
> +	int fd;
> +
> +	igt_debug("Restoring runtime power management for PCI '%04x:%02x:%02x.%01x' '%s'\n",
> +		  pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func, control);
> +
> +	snprintf(name, PATH_MAX, "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/power/control",
> +		 pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func);
> +
> +	fd = open(name, O_WRONLY);
> +	igt_assert_f(fd >= 0, "Can't open control\n");
> +
> +	igt_assert(write(fd, control, len) == len);
> +	close(fd);
> +}
> +
> +/**
> + * igt_pm_restore_pci_card_runtime_pm:
> + * @pci_dev: root port pci_dev.
> + * Restore power control attribute for all PCI endpoints devices for a given
> + * root port.
> + */
> +void igt_pm_restore_pci_card_runtime_pm(void)
> +{
> +	int i = 0;
> +
> +	for (i = 0; i < MAX_PCI_DEVICES; i++) {
> +		if (!__igt_pm_pci_control[i].pci_dev)
> +			break;
> +
> +		igt_pm_restore_pci_dev_runtime_pm(__igt_pm_pci_control[i].pci_dev,
> +						  __igt_pm_pci_control[i].control,
> +						  sizeof(__igt_pm_pci_control[i].control));
> +	}
> +
> +	memset(__igt_pm_pci_control, 0, sizeof(__igt_pm_pci_control));
> +	pci_system_cleanup();
> +}
> +
> +static void igt_pm_print_pci_dev_runtime_status(struct pci_device *pci_dev)
> +{
> +	char name[PATH_MAX], runtime_status[64];
> +	int fd, n_read;
> +
> +	snprintf(name, PATH_MAX, "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/power/runtime_status",
> +		 pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func);
> +
> +	fd = open(name, O_RDONLY);
> +	igt_assert_f(fd >= 0, "Can't open runtime_status\n");
> +
> +	n_read = read(fd, runtime_status, sizeof(runtime_status) - 1);
> +	igt_assert(n_read >= 0);
> +	runtime_status[n_read] = '\0';
> +	igt_info("runtime suspend status for PCI '%04x:%02x:%02x.%01x' %s\n",
> +		 pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func, runtime_status);
> +	close(fd);
> +}
> +
> +/**
> + * igt_pm_print_pci_card_runtime_status:
> + * @pci_dev: root port pci_dev.
> + * Print runtime suspend status for all PCI endpoints devices for a given
> + * root port.
> + */
> +void igt_pm_print_pci_card_runtime_status(void)
> +{
> +	int i = 0;
> +
> +	for (i = 0; i < MAX_PCI_DEVICES; i++) {
> +		if (!__igt_pm_pci_control[i].pci_dev)
> +			break;
> +
> +		igt_pm_print_pci_dev_runtime_status(__igt_pm_pci_control[i].pci_dev);
> +	}
> +}
> diff --git a/lib/igt_pm.h b/lib/igt_pm.h
> index 162d3ca3c..a5a9c4760 100644
> --- a/lib/igt_pm.h
> +++ b/lib/igt_pm.h
> @@ -46,6 +46,21 @@ enum igt_runtime_pm_status {
>  	IGT_RUNTIME_PM_STATUS_UNKNOWN,
>  };
>  
> +/* PCI ACPI firmware node real state */
> +enum igt_acpi_d_state {
> +	IGT_ACPI_D0,
> +	IGT_ACPI_D1,
> +	IGT_ACPI_D2,
> +	IGT_ACPI_D3Hot,
> +	IGT_ACPI_D3Cold,
> +	IGT_ACPI_UNKNOWN_STATE,
> +};
> +
> +struct	igt_pm_pci_dev_control {
> +	struct pci_device *pci_dev;
> +	char control[64];
> +};
> +
>  bool igt_setup_runtime_pm(int device);
>  void igt_disable_runtime_pm(void);
>  void igt_restore_runtime_pm(void);
> @@ -54,5 +69,11 @@ 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);
> +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);
> +void igt_pm_setup_pci_card_runtime_pm(struct pci_device *pci_dev);
> +void igt_pm_restore_pci_card_runtime_pm(void);
> +void igt_pm_print_pci_card_runtime_status(void);
>  
>  #endif /* IGT_PM_H */
> -- 
> 2.26.2
>