Re: [PATCH v9 15/22] powerpc/powernv: Functions to get/set PCI slot state

[Alistair Popple <alistair@popple.id.au>]

Gavin,

On Tue, 3 May 2016 23:22:46 Gavin Shan wrote:
> This exports 4 functions, which base on the corresponding OPAL
> APIs to get/set PCI slot status. Those functions are going to
> be used by PowerNV PCI hotplug driver:
> 
>    pnv_pci_get_device_tree()    opal_get_device_tree()
>    pnv_pci_get_presence_state() opal_pci_get_presence_state()
>    pnv_pci_get_power_state()    opal_pci_get_power_state()
>    pnv_pci_set_power_state()    opal_pci_set_power_state()
> 
> Besides, the patch also exports pnv_pci_hotplug_notifier_{register,
> unregister}() to allow registration and unregistration of PCI hotplug
> notifier, which will be used to receive PCI hotplug message from
> skiboot firmware in PowerNV PCI hotplug driver.
> 
> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
>  arch/powerpc/include/asm/opal-api.h            |  18 ++++-
>  arch/powerpc/include/asm/opal.h                |   5 ++
>  arch/powerpc/include/asm/pnv-pci.h             |   7 ++
>  arch/powerpc/platforms/powernv/opal-wrappers.S |   5 ++
>  arch/powerpc/platforms/powernv/pci.c           | 102 
+++++++++++++++++++++++++
>  5 files changed, 136 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/include/asm/opal-api.h 
b/arch/powerpc/include/asm/opal-api.h
> index 9bb8ddf..728e04e 100644
> --- a/arch/powerpc/include/asm/opal-api.h
> +++ b/arch/powerpc/include/asm/opal-api.h
> @@ -158,7 +158,12 @@
>  #define OPAL_LEDS_SET_INDICATOR			115
>  #define OPAL_CEC_REBOOT2			116
>  #define OPAL_CONSOLE_FLUSH			117
> -#define OPAL_LAST				117
> +#define OPAL_GET_DEVICE_TREE			118
> +#define OPAL_PCI_GET_PRESENCE_STATE		119
> +#define OPAL_PCI_GET_POWER_STATE		120
> +#define OPAL_PCI_SET_POWER_STATE		121
> +#define OPAL_PCI_POLL2				122
> +#define OPAL_LAST				122
>  
>  /* Device tree flags */
>  
> @@ -344,6 +349,16 @@ enum OpalPciResetState {
>  	OPAL_ASSERT_RESET   = 1
>  };
>  
> +enum OpalPciSlotPresentenceState {
> +	OPAL_PCI_SLOT_EMPTY	= 0,
> +	OPAL_PCI_SLOT_PRESENT	= 1
> +};
> +
> +enum OpalPciSlotPowerState {
> +	OPAL_PCI_SLOT_POWER_OFF	= 0,
> +	OPAL_PCI_SLOT_POWER_ON	= 1
> +};
> +
>  enum OpalSlotLedType {
>  	OPAL_SLOT_LED_TYPE_ID = 0,	/* IDENTIFY LED */
>  	OPAL_SLOT_LED_TYPE_FAULT = 1,	/* FAULT LED */
> @@ -378,6 +393,7 @@ enum opal_msg_type {
>  	OPAL_MSG_DPO		= 5,
>  	OPAL_MSG_PRD		= 6,
>  	OPAL_MSG_OCC		= 7,
> +	OPAL_MSG_PCI_HOTPLUG	= 8,
>  	OPAL_MSG_TYPE_MAX,
>  };
>  
> diff --git a/arch/powerpc/include/asm/opal.h 
b/arch/powerpc/include/asm/opal.h
> index 348132c..1a83c80 100644
> --- a/arch/powerpc/include/asm/opal.h
> +++ b/arch/powerpc/include/asm/opal.h
> @@ -209,6 +209,11 @@ int64_t opal_flash_write(uint64_t id, uint64_t offset, 
uint64_t buf,
>  		uint64_t size, uint64_t token);
>  int64_t opal_flash_erase(uint64_t id, uint64_t offset, uint64_t size,
>  		uint64_t token);
> +int64_t opal_get_device_tree(uint32_t phandle, uint64_t buf, uint64_t len);
> +int64_t opal_pci_get_presence_state(uint64_t id, uint64_t data);
> +int64_t opal_pci_get_power_state(uint64_t id, uint64_t data);
> +int64_t opal_pci_set_power_state(uint64_t id, uint64_t data);
> +int64_t opal_pci_poll2(uint64_t id, uint64_t data);
>  
>  /* Internal functions */
>  extern int early_init_dt_scan_opal(unsigned long node, const char *uname,
> diff --git a/arch/powerpc/include/asm/pnv-pci.h 
b/arch/powerpc/include/asm/pnv-pci.h
> index c607902..8db7439 100644
> --- a/arch/powerpc/include/asm/pnv-pci.h
> +++ b/arch/powerpc/include/asm/pnv-pci.h
> @@ -17,6 +17,13 @@
>  #define PCI_SLOT_ID(phb_id, bdfn)	\
>  	(PCI_SLOT_ID_PREFIX | ((uint64_t)(bdfn) << 16) | (phb_id))
>  
> +extern int pnv_pci_get_device_tree(uint32_t phandle, void *buf, uint64_t 
len);
> +extern int pnv_pci_get_presence_state(uint64_t id, uint8_t *state);
> +extern int pnv_pci_get_power_state(uint64_t id, uint8_t *state);
> +extern int pnv_pci_set_power_state(uint64_t id, uint8_t state);
> +extern int pnv_pci_hotplug_notifier_register(struct notifier_block *nb);
> +extern int pnv_pci_hotplug_notifier_unregister(struct notifier_block *nb);
> +
>  int pnv_phb_to_cxl_mode(struct pci_dev *dev, uint64_t mode);
>  int pnv_cxl_ioda_msi_setup(struct pci_dev *dev, unsigned int hwirq,
>  			   unsigned int virq);
> diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S 
b/arch/powerpc/platforms/powernv/opal-wrappers.S
> index e45b88a..60397d2 100644
> --- a/arch/powerpc/platforms/powernv/opal-wrappers.S
> +++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
> @@ -302,3 +302,8 @@ OPAL_CALL(opal_prd_msg,				
OPAL_PRD_MSG);
>  OPAL_CALL(opal_leds_get_ind,			OPAL_LEDS_GET_INDICATOR);
>  OPAL_CALL(opal_leds_set_ind,			OPAL_LEDS_SET_INDICATOR);
>  OPAL_CALL(opal_console_flush,			OPAL_CONSOLE_FLUSH);
> +OPAL_CALL(opal_get_device_tree,			OPAL_GET_DEVICE_TREE);
> +OPAL_CALL(opal_pci_get_presence_state,		
OPAL_PCI_GET_PRESENCE_STATE);
> +OPAL_CALL(opal_pci_get_power_state,		OPAL_PCI_GET_POWER_STATE);
> +OPAL_CALL(opal_pci_set_power_state,		OPAL_PCI_SET_POWER_STATE);
> +OPAL_CALL(opal_pci_poll2,			OPAL_PCI_POLL2);
> diff --git a/arch/powerpc/platforms/powernv/pci.c 
b/arch/powerpc/platforms/powernv/pci.c
> index 67a33e9..6e10ac4 100644
> --- a/arch/powerpc/platforms/powernv/pci.c
> +++ b/arch/powerpc/platforms/powernv/pci.c
> @@ -42,6 +42,108 @@
>  #define cfg_dbg(fmt...)	do { } while(0)
>  //#define cfg_dbg(fmt...)	printk(fmt)
>  
> +int pnv_pci_get_device_tree(uint32_t phandle, void *buf, uint64_t len)
> +{
> +	int64_t rc;
> +
> +	if (!opal_check_token(OPAL_GET_DEVICE_TREE))
> +		return -ENXIO;
> +
> +	rc = opal_get_device_tree(phandle, (uint64_t)buf, len);
> +	if (rc != OPAL_SUCCESS)
> +		return -EIO;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(pnv_pci_get_device_tree);
> +
> +static int pnv_pci_poll2(uint64_t id, uint8_t *state)
> +{
> +	int64_t rc;
> +
> +	if (!opal_check_token(OPAL_PCI_POLL2))
> +		return -ENXIO;
> +
> +	while (1) {
> +		rc = opal_pci_poll2(id, (uint64_t)state);
> +		if (rc <= OPAL_SUCCESS)
> +			break;
> +
> +		if (system_state < SYSTEM_RUNNING)
> +			udelay(1000 * rc);
> +		else
> +			msleep(rc);

As we discussed offline I think this interface needs to change. Skiboot now 
has good support for timers which can be scheduled for cranking state 
machines, etc. rather than relying on the kernel.

If the kernel needs to wait for completion it can poll on a relevant status by 
using opal_pci_get_power_state() to return the current state for example, or 
perhaps better it could wait to receive a message or interrupt asynchronously.

Regards,

Alistair

> +	}
> +
> +	if (rc != OPAL_SUCCESS)
> +		return -EIO;
> +
> +	return 0;
> +}
> +
> +int pnv_pci_get_presence_state(uint64_t id, uint8_t *state)
> +{
> +	int64_t rc;
> +
> +	if (!opal_check_token(OPAL_PCI_GET_PRESENCE_STATE))
> +		return -ENXIO;
> +
> +	rc = opal_pci_get_presence_state(id, (uint64_t)state);
> +	if (rc == OPAL_SUCCESS)
> +		return 0;
> +	else if (rc < OPAL_SUCCESS)
> +		return -EIO;
> +
> +	return pnv_pci_poll2(id, state);
> +}
> +EXPORT_SYMBOL_GPL(pnv_pci_get_presence_state);
> +
> +int pnv_pci_get_power_state(uint64_t id, uint8_t *state)
> +{
> +	int64_t rc;
> +
> +	if (!opal_check_token(OPAL_PCI_GET_POWER_STATE))
> +		return -ENXIO;
> +
> +	rc = opal_pci_get_power_state(id, (uint64_t)state);
> +	if (rc == OPAL_SUCCESS)
> +		return 0;
> +	else if (rc < OPAL_SUCCESS)
> +		return -EIO;
> +
> +	return pnv_pci_poll2(id, state);
> +}
> +EXPORT_SYMBOL_GPL(pnv_pci_get_power_state);
> +
> +int pnv_pci_set_power_state(uint64_t id, uint8_t state)
> +{
> +	int64_t rc;
> +
> +	if (!opal_check_token(OPAL_PCI_SET_POWER_STATE))
> +		return -ENXIO;
> +
> +	rc = opal_pci_set_power_state(id, (uint64_t)&state);
> +	if (rc == OPAL_SUCCESS)
> +		return 0;
> +	else if (rc < OPAL_SUCCESS)
> +		return -EIO;
> +
> +	return pnv_pci_poll2(id, &state);
> +}
> +EXPORT_SYMBOL_GPL(pnv_pci_set_power_state);
> +
> +int pnv_pci_hotplug_notifier_register(struct notifier_block *nb)
> +{
> +	return opal_message_notifier_register(OPAL_MSG_PCI_HOTPLUG, nb);
> +}
> +EXPORT_SYMBOL_GPL(pnv_pci_hotplug_notifier_register);
> +
> +int pnv_pci_hotplug_notifier_unregister(struct notifier_block *nb)
> +{
> +	return opal_message_notifier_unregister(OPAL_MSG_PCI_HOTPLUG, nb);
> +}
> +EXPORT_SYMBOL_GPL(pnv_pci_hotplug_notifier_unregister);
> +
>  #ifdef CONFIG_PCI_MSI
>  int pnv_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
>  {
>