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platform-msi: Track shared domain allocation 

We have two flavours of platform-MSI:

- MSIs generated by devices for themselves (the usual case)

- MSIs generated on behalf of other devices, as the generating
  device is some form of bridge (either a wire-to-MSI bridge,
  or even a non-transparent PCI bridge that repaints the PCI
  requester ID).

In the latter case, the underlying interrupt architecture may need
to track this in order to keep the mapping alive even when no MSI
are currently being generated.

Add a set of flags to the generic msi_alloc_info_t structure, as
well as the MSI_ALLOC_FLAGS_PROXY_DEVICE flag that will get
advertized by the platform-MSI code when allocating an irqdomain
for a device.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Tested-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/20201129135208.680293-2-maz@kernel.org
zero-sugar-mainline-defconfig
Marc Zyngier 2020-11-29 13:52:06 +00:00
parent fc6c7cd387
commit 91f90daa4f
2 changed files with 11 additions and 0 deletions
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7
drivers/base/platform-msi.c
View File

@ -59,9 +59,15 @@ static int platform_msi_init(struct irq_domain *domain,
return irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
info->chip, info->chip_data);
}
static void platform_msi_set_proxy_dev(msi_alloc_info_t *arg)
{
arg->flags |= MSI_ALLOC_FLAGS_PROXY_DEVICE;
}
#else
#define platform_msi_set_desc NULL
#define platform_msi_init NULL
#define platform_msi_set_proxy_dev(x) do {} while(0)
#endif
static void platform_msi_update_dom_ops(struct msi_domain_info *info)
@ -343,6 +349,7 @@ __platform_msi_create_device_domain(struct device *dev,
if (!domain)
goto free_priv;
platform_msi_set_proxy_dev(&data->arg);
err = msi_domain_prepare_irqs(domain->parent, dev, nvec, &data->arg);
if (err)
goto free_domain;

4
include/asm-generic/msi.h
View File

@ -22,12 +22,16 @@ struct msi_desc;
typedef struct msi_alloc_info {
struct msi_desc *desc;
irq_hw_number_t hwirq;
unsigned long flags;
union {
unsigned long ul;
void *ptr;
} scratchpad[NUM_MSI_ALLOC_SCRATCHPAD_REGS];
} msi_alloc_info_t;
/* Device generating MSIs is proxying for another device */
#define MSI_ALLOC_FLAGS_PROXY_DEVICE (1UL << 0)
#define GENERIC_MSI_DOMAIN_OPS 1
#endif