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nxpfranklibjorn-helgaas
nxpfrankli
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bjorn-helgaas
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PCI: endpoint: pci-epf-test: Add doorbell test support
Add doorbell support by allocating a dedicated BAR using the pci_epf_alloc_doorbell() API and mapping the Endpoint MSI controller message data address to it. The data to be written in the message address is stored in the 'pci_epf_test_reg::doorbell_data' register. Finally, the RC can trigger doorbell in the Endpoint by writing the content of 'doorbell_data' register to the offset specified in 'doorbell_offset' of the 'doorbell_bar' BAR. Triggering of the doorbell is detected by pci_epf_test_doorbell_handler(), which is bound to the doorbell IRQ. On successful completion, STATUS_DOORBELL_SUCCESS status is set in the above mentioned handler. To avoid breaking compatibility between host and endpoint, add two new commands: COMMAND_ENABLE_DOORBELL and COMMAND_DISABLE_DOORBELL. The doorbell is allocated when COMMAND_ENABLE_DOORBELL command is called and destroyed when COMMAND_DISABLE_DOORBELL is called. This doorbell feature only works when both RC and EP drivers support it. If one of them doesn't support the feature, the testcase will fail. Signed-off-by: Frank Li <Frank.Li@nxp.com> [mani: code cleanups and reworded commit message] Signed-off-by: Manivannan Sadhasivam <mani@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Tested-by: Niklas Cassel <cassel@kernel.org> Link: https://patch.msgid.link/20250710-ep-msi-v21-6-57683fc7fb25@nxp.com
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‎drivers/pci/endpoint/functions/pci-epf-test.c‎

Lines changed: 130 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -11,12 +11,14 @@
1111
#include <linux/dmaengine.h>
1212
#include <linux/io.h>
1313
#include <linux/module.h>
14+
#include <linux/msi.h>
1415
#include <linux/slab.h>
1516
#include <linux/pci_ids.h>
1617
#include <linux/random.h>
1718

1819
#include <linux/pci-epc.h>
1920
#include <linux/pci-epf.h>
21+
#include <linux/pci-ep-msi.h>
2022
#include <linux/pci_regs.h>
2123

2224
#define IRQ_TYPE_INTX 0
@@ -29,6 +31,8 @@
2931
#define COMMAND_READ BIT(3)
3032
#define COMMAND_WRITE BIT(4)
3133
#define COMMAND_COPY BIT(5)
34+
#define COMMAND_ENABLE_DOORBELL BIT(6)
35+
#define COMMAND_DISABLE_DOORBELL BIT(7)
3236

3337
#define STATUS_READ_SUCCESS BIT(0)
3438
#define STATUS_READ_FAIL BIT(1)
@@ -39,6 +43,11 @@
3943
#define STATUS_IRQ_RAISED BIT(6)
4044
#define STATUS_SRC_ADDR_INVALID BIT(7)
4145
#define STATUS_DST_ADDR_INVALID BIT(8)
46+
#define STATUS_DOORBELL_SUCCESS BIT(9)
47+
#define STATUS_DOORBELL_ENABLE_SUCCESS BIT(10)
48+
#define STATUS_DOORBELL_ENABLE_FAIL BIT(11)
49+
#define STATUS_DOORBELL_DISABLE_SUCCESS BIT(12)
50+
#define STATUS_DOORBELL_DISABLE_FAIL BIT(13)
4251

4352
#define FLAG_USE_DMA BIT(0)
4453

@@ -66,6 +75,7 @@ struct pci_epf_test {
6675
bool dma_supported;
6776
bool dma_private;
6877
const struct pci_epc_features *epc_features;
78+
struct pci_epf_bar db_bar;
6979
};
7080

7181
struct pci_epf_test_reg {
@@ -80,6 +90,9 @@ struct pci_epf_test_reg {
8090
__le32 irq_number;
8191
__le32 flags;
8292
__le32 caps;
93+
__le32 doorbell_bar;
94+
__le32 doorbell_offset;
95+
__le32 doorbell_data;
8396
} __packed;
8497

8598
static struct pci_epf_header test_header = {
@@ -667,6 +680,115 @@ static void pci_epf_test_raise_irq(struct pci_epf_test *epf_test,
667680
}
668681
}
669682

683+
static irqreturn_t pci_epf_test_doorbell_handler(int irq, void *data)
684+
{
685+
struct pci_epf_test *epf_test = data;
686+
enum pci_barno test_reg_bar = epf_test->test_reg_bar;
687+
struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
688+
u32 status = le32_to_cpu(reg->status);
689+
690+
status |= STATUS_DOORBELL_SUCCESS;
691+
reg->status = cpu_to_le32(status);
692+
pci_epf_test_raise_irq(epf_test, reg);
693+
694+
return IRQ_HANDLED;
695+
}
696+
697+
static void pci_epf_test_doorbell_cleanup(struct pci_epf_test *epf_test)
698+
{
699+
struct pci_epf_test_reg *reg = epf_test->reg[epf_test->test_reg_bar];
700+
struct pci_epf *epf = epf_test->epf;
701+
702+
free_irq(epf->db_msg[0].virq, epf_test);
703+
reg->doorbell_bar = cpu_to_le32(NO_BAR);
704+
705+
pci_epf_free_doorbell(epf);
706+
}
707+
708+
static void pci_epf_test_enable_doorbell(struct pci_epf_test *epf_test,
709+
struct pci_epf_test_reg *reg)
710+
{
711+
u32 status = le32_to_cpu(reg->status);
712+
struct pci_epf *epf = epf_test->epf;
713+
struct pci_epc *epc = epf->epc;
714+
struct msi_msg *msg;
715+
enum pci_barno bar;
716+
size_t offset;
717+
int ret;
718+
719+
ret = pci_epf_alloc_doorbell(epf, 1);
720+
if (ret)
721+
goto set_status_err;
722+
723+
msg = &epf->db_msg[0].msg;
724+
bar = pci_epc_get_next_free_bar(epf_test->epc_features, epf_test->test_reg_bar + 1);
725+
if (bar < BAR_0)
726+
goto err_doorbell_cleanup;
727+
728+
ret = request_irq(epf->db_msg[0].virq, pci_epf_test_doorbell_handler, 0,
729+
"pci-ep-test-doorbell", epf_test);
730+
if (ret) {
731+
dev_err(&epf->dev,
732+
"Failed to request doorbell IRQ: %d\n",
733+
epf->db_msg[0].virq);
734+
goto err_doorbell_cleanup;
735+
}
736+
737+
reg->doorbell_data = cpu_to_le32(msg->data);
738+
reg->doorbell_bar = cpu_to_le32(bar);
739+
740+
msg = &epf->db_msg[0].msg;
741+
ret = pci_epf_align_inbound_addr(epf, bar, ((u64)msg->address_hi << 32) | msg->address_lo,
742+
&epf_test->db_bar.phys_addr, &offset);
743+
744+
if (ret)
745+
goto err_doorbell_cleanup;
746+
747+
reg->doorbell_offset = cpu_to_le32(offset);
748+
749+
epf_test->db_bar.barno = bar;
750+
epf_test->db_bar.size = epf->bar[bar].size;
751+
epf_test->db_bar.flags = epf->bar[bar].flags;
752+
753+
ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no, &epf_test->db_bar);
754+
if (ret)
755+
goto err_doorbell_cleanup;
756+
757+
status |= STATUS_DOORBELL_ENABLE_SUCCESS;
758+
reg->status = cpu_to_le32(status);
759+
return;
760+
761+
err_doorbell_cleanup:
762+
pci_epf_test_doorbell_cleanup(epf_test);
763+
set_status_err:
764+
status |= STATUS_DOORBELL_ENABLE_FAIL;
765+
reg->status = cpu_to_le32(status);
766+
}
767+
768+
static void pci_epf_test_disable_doorbell(struct pci_epf_test *epf_test,
769+
struct pci_epf_test_reg *reg)
770+
{
771+
enum pci_barno bar = le32_to_cpu(reg->doorbell_bar);
772+
u32 status = le32_to_cpu(reg->status);
773+
struct pci_epf *epf = epf_test->epf;
774+
struct pci_epc *epc = epf->epc;
775+
776+
if (bar < BAR_0)
777+
goto set_status_err;
778+
779+
pci_epf_test_doorbell_cleanup(epf_test);
780+
pci_epc_clear_bar(epc, epf->func_no, epf->vfunc_no, &epf_test->db_bar);
781+
782+
status |= STATUS_DOORBELL_DISABLE_SUCCESS;
783+
reg->status = cpu_to_le32(status);
784+
785+
return;
786+
787+
set_status_err:
788+
status |= STATUS_DOORBELL_DISABLE_FAIL;
789+
reg->status = cpu_to_le32(status);
790+
}
791+
670792
static void pci_epf_test_cmd_handler(struct work_struct *work)
671793
{
672794
u32 command;
@@ -714,6 +836,14 @@ static void pci_epf_test_cmd_handler(struct work_struct *work)
714836
pci_epf_test_copy(epf_test, reg);
715837
pci_epf_test_raise_irq(epf_test, reg);
716838
break;
839+
case COMMAND_ENABLE_DOORBELL:
840+
pci_epf_test_enable_doorbell(epf_test, reg);
841+
pci_epf_test_raise_irq(epf_test, reg);
842+
break;
843+
case COMMAND_DISABLE_DOORBELL:
844+
pci_epf_test_disable_doorbell(epf_test, reg);
845+
pci_epf_test_raise_irq(epf_test, reg);
846+
break;
717847
default:
718848
dev_err(dev, "Invalid command 0x%x\n", command);
719849
break;

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