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PCI: endpoint: pci-epf-test: Reuse pre-exposed doorbell targets

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pci-epf-test advertises the doorbell target to the RC as a BAR number
and an offset, and the RC rings the doorbell with a single DWORD MMIO
write.

Some doorbell backends may report that the doorbell target is already
exposed via a platform-owned fixed BAR (db_msg[0].bar/offset). In that
case, reuse the pre-exposed window and do not reprogram the BAR with
pci_epc_set_bar().

Also honor db_msg[0].irq_flags when requesting the doorbell IRQ, and
only restore the original BAR mapping on disable if pci-epf-test
programmed it.

Signed-off-by: Koichiro Den <den@valinux.co.jp>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
[bhelgaas: wrap comment]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260414141514.1341429-7-den@valinux.co.jp
This commit is contained in:
Koichiro Den
2026-04-14 23:15:13 +09:00
committed by Bjorn Helgaas
parent 0c3f82a584
commit 8fda2dd209
1 changed files with 59 additions and 27 deletions
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86
drivers/pci/endpoint/functions/pci-epf-test.c
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@@ -94,6 +94,7 @@ struct pci_epf_test {
bool dma_private;
const struct pci_epc_features *epc_features;
struct pci_epf_bar db_bar;
bool db_bar_programmed;
size_t bar_size[PCI_STD_NUM_BARS];
};
@@ -733,7 +734,9 @@ static void pci_epf_test_enable_doorbell(struct pci_epf_test *epf_test,
{
u32 status = le32_to_cpu(reg->status);
struct pci_epf *epf = epf_test->epf;
struct pci_epf_doorbell_msg *db;
struct pci_epc *epc = epf->epc;
unsigned long irq_flags;
struct msi_msg *msg;
enum pci_barno bar;
size_t offset;
@@ -743,13 +746,28 @@ static void pci_epf_test_enable_doorbell(struct pci_epf_test *epf_test,
if (ret)
goto set_status_err;
msg = &epf->db_msg[0].msg;
bar = pci_epc_get_next_free_bar(epf_test->epc_features, epf_test->test_reg_bar + 1);
if (bar < BAR_0)
goto err_doorbell_cleanup;
db = &epf->db_msg[0];
msg = &db->msg;
epf_test->db_bar_programmed = false;
if (db->bar != NO_BAR) {
/*
* The doorbell target is already exposed via a platform-owned
* fixed BAR
*/
bar = db->bar;
offset = db->offset;
} else {
bar = pci_epc_get_next_free_bar(epf_test->epc_features,
epf_test->test_reg_bar + 1);
if (bar < BAR_0)
goto err_doorbell_cleanup;
}
irq_flags = epf->db_msg[0].irq_flags | IRQF_ONESHOT;
ret = request_threaded_irq(epf->db_msg[0].virq, NULL,
pci_epf_test_doorbell_handler, IRQF_ONESHOT,
pci_epf_test_doorbell_handler, irq_flags,
"pci-ep-test-doorbell", epf_test);
if (ret) {
dev_err(&epf->dev,
@@ -761,22 +779,30 @@ static void pci_epf_test_enable_doorbell(struct pci_epf_test *epf_test,
reg->doorbell_data = cpu_to_le32(msg->data);
reg->doorbell_bar = cpu_to_le32(bar);
msg = &epf->db_msg[0].msg;
ret = pci_epf_align_inbound_addr(epf, bar, ((u64)msg->address_hi << 32) | msg->address_lo,
&epf_test->db_bar.phys_addr, &offset);
if (db->bar == NO_BAR) {
ret = pci_epf_align_inbound_addr(epf, bar,
((u64)msg->address_hi << 32) |
msg->address_lo,
&epf_test->db_bar.phys_addr,
&offset);
if (ret)
goto err_free_irq;
if (ret)
goto err_free_irq;
}
reg->doorbell_offset = cpu_to_le32(offset);
epf_test->db_bar.barno = bar;
epf_test->db_bar.size = epf->bar[bar].size;
epf_test->db_bar.flags = epf->bar[bar].flags;
if (db->bar == NO_BAR) {
epf_test->db_bar.barno = bar;
epf_test->db_bar.size = epf->bar[bar].size;
epf_test->db_bar.flags = epf->bar[bar].flags;
ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no, &epf_test->db_bar);
if (ret)
goto err_free_irq;
ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no, &epf_test->db_bar);
if (ret)
goto err_free_irq;
epf_test->db_bar_programmed = true;
}
status |= STATUS_DOORBELL_ENABLE_SUCCESS;
reg->status = cpu_to_le32(status);
@@ -806,17 +832,23 @@ static void pci_epf_test_disable_doorbell(struct pci_epf_test *epf_test,
free_irq(epf->db_msg[0].virq, epf_test);
pci_epf_test_doorbell_cleanup(epf_test);
/*
* The doorbell feature temporarily overrides the inbound translation
* to point to the address stored in epf_test->db_bar.phys_addr, i.e.,
* it calls set_bar() twice without ever calling clear_bar(), as
* calling clear_bar() would clear the BAR's PCI address assigned by
* the host. Thus, when disabling the doorbell, restore the inbound
* translation to point to the memory allocated for the BAR.
*/
ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no, &epf->bar[bar]);
if (ret)
goto set_status_err;
if (epf_test->db_bar_programmed) {
/*
* The doorbell feature temporarily overrides the inbound
* translation to point to the address stored in
* epf_test->db_bar.phys_addr, i.e., it calls set_bar()
* twice without ever calling clear_bar(), as calling
* clear_bar() would clear the BAR's PCI address assigned
* by the host. Thus, when disabling the doorbell, restore
* the inbound translation to point to the memory allocated
* for the BAR.
*/
ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no, &epf->bar[bar]);
if (ret)
goto set_status_err;
epf_test->db_bar_programmed = false;
}
status |= STATUS_DOORBELL_DISABLE_SUCCESS;
reg->status = cpu_to_le32(status);