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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
This commit is contained in:
Frank Li 2025-07-10 15:13:52 -04:00 committed by Bjorn Helgaas
parent 4ff4252a23
commit eff0c286aa
1 changed files with 130 additions and 0 deletions
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130
drivers/pci/endpoint/functions/pci-epf-test.c
View File

@ -11,12 +11,14 @@
#include <linux/dmaengine.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/msi.h>
#include <linux/slab.h>
#include <linux/pci_ids.h>
#include <linux/random.h>
#include <linux/pci-epc.h>
#include <linux/pci-epf.h>
#include <linux/pci-ep-msi.h>
#include <linux/pci_regs.h>
#define IRQ_TYPE_INTX 0
@ -29,6 +31,8 @@
#define COMMAND_READ BIT(3)
#define COMMAND_WRITE BIT(4)
#define COMMAND_COPY BIT(5)
#define COMMAND_ENABLE_DOORBELL BIT(6)
#define COMMAND_DISABLE_DOORBELL BIT(7)
#define STATUS_READ_SUCCESS BIT(0)
#define STATUS_READ_FAIL BIT(1)
@ -39,6 +43,11 @@
#define STATUS_IRQ_RAISED BIT(6)
#define STATUS_SRC_ADDR_INVALID BIT(7)
#define STATUS_DST_ADDR_INVALID BIT(8)
#define STATUS_DOORBELL_SUCCESS BIT(9)
#define STATUS_DOORBELL_ENABLE_SUCCESS BIT(10)
#define STATUS_DOORBELL_ENABLE_FAIL BIT(11)
#define STATUS_DOORBELL_DISABLE_SUCCESS BIT(12)
#define STATUS_DOORBELL_DISABLE_FAIL BIT(13)
#define FLAG_USE_DMA BIT(0)
@ -66,6 +75,7 @@ struct pci_epf_test {
bool dma_supported;
bool dma_private;
const struct pci_epc_features *epc_features;
struct pci_epf_bar db_bar;
};
struct pci_epf_test_reg {
@ -80,6 +90,9 @@ struct pci_epf_test_reg {
__le32 irq_number;
__le32 flags;
__le32 caps;
__le32 doorbell_bar;
__le32 doorbell_offset;
__le32 doorbell_data;
} __packed;
static struct pci_epf_header test_header = {
@ -667,6 +680,115 @@ static void pci_epf_test_raise_irq(struct pci_epf_test *epf_test,
}
}
static irqreturn_t pci_epf_test_doorbell_handler(int irq, void *data)
{
struct pci_epf_test *epf_test = data;
enum pci_barno test_reg_bar = epf_test->test_reg_bar;
struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
u32 status = le32_to_cpu(reg->status);
status |= STATUS_DOORBELL_SUCCESS;
reg->status = cpu_to_le32(status);
pci_epf_test_raise_irq(epf_test, reg);
return IRQ_HANDLED;
}
static void pci_epf_test_doorbell_cleanup(struct pci_epf_test *epf_test)
{
struct pci_epf_test_reg *reg = epf_test->reg[epf_test->test_reg_bar];
struct pci_epf *epf = epf_test->epf;
free_irq(epf->db_msg[0].virq, epf_test);
reg->doorbell_bar = cpu_to_le32(NO_BAR);
pci_epf_free_doorbell(epf);
}
static void pci_epf_test_enable_doorbell(struct pci_epf_test *epf_test,
struct pci_epf_test_reg *reg)
{
u32 status = le32_to_cpu(reg->status);
struct pci_epf *epf = epf_test->epf;
struct pci_epc *epc = epf->epc;
struct msi_msg *msg;
enum pci_barno bar;
size_t offset;
int ret;
ret = pci_epf_alloc_doorbell(epf, 1);
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;
ret = request_irq(epf->db_msg[0].virq, pci_epf_test_doorbell_handler, 0,
"pci-ep-test-doorbell", epf_test);
if (ret) {
dev_err(&epf->dev,
"Failed to request doorbell IRQ: %d\n",
epf->db_msg[0].virq);
goto err_doorbell_cleanup;
}
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 (ret)
goto err_doorbell_cleanup;
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;
ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no, &epf_test->db_bar);
if (ret)
goto err_doorbell_cleanup;
status |= STATUS_DOORBELL_ENABLE_SUCCESS;
reg->status = cpu_to_le32(status);
return;
err_doorbell_cleanup:
pci_epf_test_doorbell_cleanup(epf_test);
set_status_err:
status |= STATUS_DOORBELL_ENABLE_FAIL;
reg->status = cpu_to_le32(status);
}
static void pci_epf_test_disable_doorbell(struct pci_epf_test *epf_test,
struct pci_epf_test_reg *reg)
{
enum pci_barno bar = le32_to_cpu(reg->doorbell_bar);
u32 status = le32_to_cpu(reg->status);
struct pci_epf *epf = epf_test->epf;
struct pci_epc *epc = epf->epc;
if (bar < BAR_0)
goto set_status_err;
pci_epf_test_doorbell_cleanup(epf_test);
pci_epc_clear_bar(epc, epf->func_no, epf->vfunc_no, &epf_test->db_bar);
status |= STATUS_DOORBELL_DISABLE_SUCCESS;
reg->status = cpu_to_le32(status);
return;
set_status_err:
status |= STATUS_DOORBELL_DISABLE_FAIL;
reg->status = cpu_to_le32(status);
}
static void pci_epf_test_cmd_handler(struct work_struct *work)
{
u32 command;
@ -714,6 +836,14 @@ static void pci_epf_test_cmd_handler(struct work_struct *work)
pci_epf_test_copy(epf_test, reg);
pci_epf_test_raise_irq(epf_test, reg);
break;
case COMMAND_ENABLE_DOORBELL:
pci_epf_test_enable_doorbell(epf_test, reg);
pci_epf_test_raise_irq(epf_test, reg);
break;
case COMMAND_DISABLE_DOORBELL:
pci_epf_test_disable_doorbell(epf_test, reg);
pci_epf_test_raise_irq(epf_test, reg);
break;
default:
dev_err(dev, "Invalid command 0x%x\n", command);
break;