Re: [PATCH v13 14/21] PCI: microchip: Add get_events() callback and add PLDA get_event()

[Minda Chen <minda.chen@starfivetech.com>]

On 2023/12/28 0:31, Lorenzo Pieralisi wrote:
> On Thu, Dec 14, 2023 at 03:28:32PM +0800, Minda Chen wrote:
>> PolarFire implements its own PCIe interrupts, additional to the regular
>> PCIe interrupts, due to lack of an MSI controller, so the interrupt to
>> event number mapping is different to the PLDA local interrupts,
> 
> I am sorry I don't understand what you mean here.
> 
> "its own PCIe interrupts" ?
> 
> "regular PCIe interrupts" ?
> 
> "PLDA local interrupts" ?
> 
> Can you spell out what those are referring to please ?
> 
> Thanks,
> Lorenzo
>

"its own PCIe interrupts" ?

PolarFire SoC PCIe implement 11 interrupt in their platform. 
(can be found in pcie-microchip-host.c:87)

#define EVENT_PCIE_L2_EXIT                      0
#define EVENT_PCIE_HOTRST_EXIT                  1
#define EVENT_PCIE_DLUP_EXIT                    2
#define EVENT_SEC_TX_RAM_SEC_ERR                3
#define EVENT_SEC_RX_RAM_SEC_ERR                4
#define EVENT_SEC_PCIE2AXI_RAM_SEC_ERR          5
#define EVENT_SEC_AXI2PCIE_RAM_SEC_ERR          6
#define EVENT_DED_TX_RAM_DED_ERR                7
#define EVENT_DED_RX_RAM_DED_ERR                8
#define EVENT_DED_PCIE2AXI_RAM_DED_ERR          9
#define EVENT_DED_AXI2PCIE_RAM_DED_ERR          10

"regular PCIe interrupts" ?
 
"PLDA local interrupts" ?

Actually they are the same. I will change this.
PLDA interrupt register graph in this patch.
 
>> necessitating a custom get_events() implementation.
>> 
>> plda_get_events() adds interrupt register to PLDA local event num mapping
>> codes except DMA engine interrupt events. The DMA engine interrupt events
>> are implemented by vendors.
>> 
>> Signed-off-by: Minda Chen <minda.chen@starfivetech.com>
>> Acked-by: Conor Dooley <conor.dooley@microchip.com>
>> ---
>>  .../pci/controller/plda/pcie-microchip-host.c | 35 ++++++++++++++++++-
>>  drivers/pci/controller/plda/pcie-plda.h       | 33 +++++++++++++++++
>>  2 files changed, 67 insertions(+), 1 deletion(-)
>> 
>> diff --git a/drivers/pci/controller/plda/pcie-microchip-host.c b/drivers/pci/controller/plda/pcie-microchip-host.c
>> index 00250781b11c..fd0d92c3d03f 100644
>> --- a/drivers/pci/controller/plda/pcie-microchip-host.c
>> +++ b/drivers/pci/controller/plda/pcie-microchip-host.c
>> @@ -627,6 +627,26 @@ static u32 mc_get_events(struct plda_pcie_rp *port)
>>  	return events;
>>  }
>>  
>> +static u32 plda_get_events(struct plda_pcie_rp *port)
>> +{
>> +	u32 events, val, origin;
>> +
>> +	origin = readl_relaxed(port->bridge_addr + ISTATUS_LOCAL);
>> +
>> +	/* Error events and doorbell events */
>> +	events = (origin & ERROR_AND_DOORBELL_MASK) >> A_ATR_EVT_POST_ERR_SHIFT;
>> +
>> +	/* INTx events */
>> +	if (origin & PM_MSI_INT_INTX_MASK)
>> +		events |= BIT(EVENT_PM_MSI_INT_INTX);
>> +
>> +	/* MSI event and sys events */
>> +	val = (origin & SYS_AND_MSI_MASK) >> PM_MSI_INT_MSI_SHIFT;
>> +	events |= val << EVENT_PM_MSI_INT_MSI;
>> +
>> +	return events;
>> +}
>> +
>>  static irqreturn_t mc_event_handler(int irq, void *dev_id)
>>  {
>>  	struct plda_pcie_rp *port = dev_id;
>> @@ -657,7 +677,7 @@ static void plda_handle_event(struct irq_desc *desc)
>>  
>>  	chained_irq_enter(chip, desc);
>>  
>> -	events = mc_get_events(port);
>> +	events = port->event_ops->get_events(port);
>>  
>>  	for_each_set_bit(bit, &events, port->num_events)
>>  		generic_handle_domain_irq(port->event_domain, bit);
>> @@ -751,6 +771,10 @@ static struct irq_chip mc_event_irq_chip = {
>>  	.irq_unmask = mc_unmask_event_irq,
>>  };
>>  
>> +static const struct plda_event_ops plda_event_ops = {
>> +	.get_events = plda_get_events,
>> +};
>> +
>>  static int plda_pcie_event_map(struct irq_domain *domain, unsigned int irq,
>>  			       irq_hw_number_t hwirq)
>>  {
>> @@ -816,6 +840,10 @@ static int mc_request_event_irq(struct plda_pcie_rp *plda, int event_irq,
>>  				0, event_cause[event].sym, plda);
>>  }
>>  
>> +static const struct plda_event_ops mc_event_ops = {
>> +	.get_events = mc_get_events,
>> +};
>> +
>>  static const struct plda_event mc_event = {
>>  	.request_event_irq = mc_request_event_irq,
>>  	.intx_event        = EVENT_LOCAL_PM_MSI_INT_INTX,
>> @@ -932,6 +960,9 @@ static int plda_init_interrupts(struct platform_device *pdev,
>>  	int i, intx_irq, msi_irq, event_irq;
>>  	int ret;
>>  
>> +	if (!port->event_ops)
>> +		port->event_ops = &plda_event_ops;
>> +
>>  	ret = plda_pcie_init_irq_domains(port);
>>  	if (ret) {
>>  		dev_err(dev, "failed creating IRQ domains\n");
>> @@ -1008,6 +1039,8 @@ static int mc_platform_init(struct pci_config_window *cfg)
>>  	if (ret)
>>  		return ret;
>>  
>> +	port->plda.event_ops = &mc_event_ops;
>> +
>>  	/* Address translation is up; safe to enable interrupts */
>>  	ret = plda_init_interrupts(pdev, &port->plda, &mc_event);
>>  	if (ret)
>> diff --git a/drivers/pci/controller/plda/pcie-plda.h b/drivers/pci/controller/plda/pcie-plda.h
>> index fba7343f9a96..dd8bc2750bfc 100644
>> --- a/drivers/pci/controller/plda/pcie-plda.h
>> +++ b/drivers/pci/controller/plda/pcie-plda.h
>> @@ -40,6 +40,7 @@
>>  #define  P_ATR_EVT_DISCARD_ERR_SHIFT		22
>>  #define  P_ATR_EVT_DOORBELL_MASK		0x00000000u
>>  #define  P_ATR_EVT_DOORBELL_SHIFT		23
>> +#define  ERROR_AND_DOORBELL_MASK		GENMASK(23, 16)
>>  #define  PM_MSI_INT_INTA_MASK			0x01000000u
>>  #define  PM_MSI_INT_INTA_SHIFT			24
>>  #define  PM_MSI_INT_INTB_MASK			0x02000000u
>> @@ -58,6 +59,7 @@
>>  #define  PM_MSI_INT_EVENTS_SHIFT		30
>>  #define  PM_MSI_INT_SYS_ERR_MASK		0x80000000u
>>  #define  PM_MSI_INT_SYS_ERR_SHIFT		31
>> +#define  SYS_AND_MSI_MASK			GENMASK(31, 28)
>>  #define  NUM_LOCAL_EVENTS			15
>>  #define ISTATUS_LOCAL				0x184
>>  #define IMASK_HOST				0x188
>> @@ -102,6 +104,36 @@
>>  #define EVENT_PM_MSI_INT_SYS_ERR		12
>>  #define NUM_PLDA_EVENTS				13
>>  
>> +/*
>> + * PLDA local interrupt register
>> + *
>> + * 31         27     23              15           7          0
>> + * +--+--+--+-+------+-+-+-+-+-+-+-+-+-----------+-----------+
>> + * |12|11|10|9| intx |7|6|5|4|3|2|1|0| DMA error | DMA end   |
>> + * +--+--+--+-+------+-+-+-+-+-+-+-+-+-----------+-----------+
>> + * 0:  AXI post error
>> + * 1:  AXI fetch error
>> + * 2:  AXI discard error
>> + * 3:  AXI doorbell
>> + * 4:  PCIe post error
>> + * 5:  PCIe fetch error
>> + * 6:  PCIe discard error
>> + * 7:  PCIe doorbell
>> + * 8:  4 INTx interruts
>> + * 9:  MSI interrupt
>> + * 10: AER event
>> + * 11: PM/LTR/Hotplug
>> + * 12: System error
>> + * DMA error : reserved for vendor implement
>> + * DMA end : reserved for vendor implement
>> + */
"PLDA local interrupts" ?

They are all the PLDA PCIe interrupts .

>> +
>> +struct plda_pcie_rp;
>> +
>> +struct plda_event_ops {
>> +	u32 (*get_events)(struct plda_pcie_rp *pcie);
>> +};
>> +
>>  struct plda_msi {
>>  	struct mutex lock;		/* Protect used bitmap */
>>  	struct irq_domain *msi_domain;
>> @@ -117,6 +149,7 @@ struct plda_pcie_rp {
>>  	struct irq_domain *event_domain;
>>  	raw_spinlock_t lock;
>>  	struct plda_msi msi;
>> +	const struct plda_event_ops *event_ops;
>>  	void __iomem *bridge_addr;
>>  	int num_events;
>>  };
>> -- 
>> 2.17.1
>>