Re: [PATCH v8 04/14] powerpc/vas: Alloc and setup IRQ and trigger port address

["Cédric Le Goater" <clg@kaod.org>]

On 3/19/20 7:14 AM, Haren Myneni wrote:
> 
> Alloc IRQ and get trigger port address for each VAS instance. Kernel
> register this IRQ per VAS instance and sets this port for each send
> window. NX interrupts the kernel when it sees page fault.

I don't understand why this is not done by the OPAL driver for each VAS 
of the system. Is the VAS unit very different from OpenCAPI regarding
the fault ? 


C.

> 
> Signed-off-by: Haren Myneni <haren@linux.ibm.com>
> ---
>  arch/powerpc/platforms/powernv/vas.c | 34 ++++++++++++++++++++++++++++------
>  arch/powerpc/platforms/powernv/vas.h |  2 ++
>  2 files changed, 30 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/powernv/vas.c b/arch/powerpc/platforms/powernv/vas.c
> index ed9cc6d..168ab68 100644
> --- a/arch/powerpc/platforms/powernv/vas.c
> +++ b/arch/powerpc/platforms/powernv/vas.c
> @@ -15,6 +15,7 @@
>  #include <linux/of_address.h>
>  #include <linux/of.h>
>  #include <asm/prom.h>
> +#include <asm/xive.h>
>  
>  #include "vas.h"
>  
> @@ -25,10 +26,12 @@
>  
>  static int init_vas_instance(struct platform_device *pdev)
>  {
> -	int rc, cpu, vasid;
> -	struct resource *res;
> -	struct vas_instance *vinst;
>  	struct device_node *dn = pdev->dev.of_node;
> +	struct vas_instance *vinst;
> +	uint32_t chipid, irq;
> +	struct resource *res;
> +	int rc, cpu, vasid;
> +	uint64_t port;
>  
>  	rc = of_property_read_u32(dn, "ibm,vas-id", &vasid);
>  	if (rc) {
> @@ -36,6 +39,12 @@ static int init_vas_instance(struct platform_device *pdev)
>  		return -ENODEV;
>  	}
>  
> +	rc = of_property_read_u32(dn, "ibm,chip-id", &chipid);
> +	if (rc) {
> +		pr_err("No ibm,chip-id property for %s?\n", pdev->name);
> +		return -ENODEV;
> +	}
> +
>  	if (pdev->num_resources != 4) {
>  		pr_err("Unexpected DT configuration for [%s, %d]\n",
>  				pdev->name, vasid);
> @@ -69,9 +78,22 @@ static int init_vas_instance(struct platform_device *pdev)
>  
>  	vinst->paste_win_id_shift = 63 - res->end;
>  
> -	pr_devel("Initialized instance [%s, %d], paste_base 0x%llx, "
> -			"paste_win_id_shift 0x%llx\n", pdev->name, vasid,
> -			vinst->paste_base_addr, vinst->paste_win_id_shift);
> +	rc = xive_native_alloc_get_irq_info(chipid, &irq, &port);
> +	if (rc)
> +		return rc;
> +
> +	vinst->virq = irq_create_mapping(NULL, irq);
> +	if (!vinst->virq) {
> +		pr_err("Inst%d: Unable to map global irq %d\n",
> +				vinst->vas_id, irq);
> +		return -EINVAL;
> +	}
> +
> +	vinst->irq_port = port;
> +	pr_devel("Initialized instance [%s, %d] paste_base 0x%llx paste_win_id_shift 0x%llx IRQ %d Port 0x%llx\n",
> +			pdev->name, vasid, vinst->paste_base_addr,
> +			vinst->paste_win_id_shift, vinst->virq,
> +			vinst->irq_port);
>  
>  	for_each_possible_cpu(cpu) {
>  		if (cpu_to_chip_id(cpu) == of_get_ibm_chip_id(dn))
> diff --git a/arch/powerpc/platforms/powernv/vas.h b/arch/powerpc/platforms/powernv/vas.h
> index 5574aec..598608b 100644
> --- a/arch/powerpc/platforms/powernv/vas.h
> +++ b/arch/powerpc/platforms/powernv/vas.h
> @@ -313,6 +313,8 @@ struct vas_instance {
>  	u64 paste_base_addr;
>  	u64 paste_win_id_shift;
>  
> +	u64 irq_port;
> +	int virq;
>  	struct mutex mutex;
>  	struct vas_window *rxwin[VAS_COP_TYPE_MAX];
>  	struct vas_window *windows[VAS_WINDOWS_PER_CHIP];
>