[PATCH v2 3/5] PCI: endpoint: pci-epf-test: add doorbell test

[Frank Li <Frank.Li@xxxxxxx>]

Add three register: doorbell_bar, doorbell_addr, doorbell_data,
doorbell_done. Call pci_epf_alloc_doorbell() all a doorbell address space.

Root complex(RC) side driver can trigger pci-epc-test's doorbell callback
handler by write doorbell_data to mapped doorbell_bar's address space.

pci-epc-test will set doorbell_done in doorbell callback.

Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---
 drivers/pci/endpoint/functions/pci-epf-test.c | 59 ++++++++++++++++++-
 1 file changed, 58 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index 1f0d2b84296a3..566549919b87b 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -11,6 +11,7 @@
 #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>
@@ -39,17 +40,21 @@
 #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 FLAG_USE_DMA			BIT(0)
 
 #define TIMER_RESOLUTION		1
 
+#define MAGIC_VERSION_MASK		GENMASK(7, 0)
+
 static struct workqueue_struct *kpcitest_workqueue;
 
 struct pci_epf_test {
 	void			*reg[PCI_STD_NUM_BARS];
 	struct pci_epf		*epf;
 	enum pci_barno		test_reg_bar;
+	enum pci_barno		doorbell_bar;
 	size_t			msix_table_offset;
 	struct delayed_work	cmd_handler;
 	struct dma_chan		*dma_chan_tx;
@@ -74,6 +79,9 @@ struct pci_epf_test_reg {
 	u32	irq_type;
 	u32	irq_number;
 	u32	flags;
+	u32	doorbell_bar;
+	u32	doorbell_addr;
+	u32	doorbell_data;
 } __packed;
 
 static struct pci_epf_header test_header = {
@@ -693,6 +701,8 @@ static void pci_epf_test_unbind(struct pci_epf *epf)
 	struct pci_epf_bar *epf_bar;
 	int bar;
 
+	pci_epf_free_doorbell(epf);
+
 	cancel_delayed_work(&epf_test->cmd_handler);
 	pci_epf_test_clean_dma_chan(epf_test);
 	for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) {
@@ -808,9 +818,22 @@ static int pci_epf_test_link_up(struct pci_epf *epf)
 	return 0;
 }
 
+static int pci_epf_test_doorbell(struct pci_epf *epf, int index)
+{
+	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
+	enum pci_barno test_reg_bar = epf_test->test_reg_bar;
+	struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
+
+	reg->status |= STATUS_DOORBELL_SUCCESS;
+	pci_epf_test_raise_irq(epf_test, reg);
+
+	return 0;
+}
+
 static const struct pci_epc_event_ops pci_epf_test_event_ops = {
 	.core_init = pci_epf_test_core_init,
 	.link_up = pci_epf_test_link_up,
+	.doorbell = pci_epf_test_doorbell,
 };
 
 static int pci_epf_test_alloc_space(struct pci_epf *epf)
@@ -859,7 +882,7 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
 		epf_bar = &epf->bar[bar];
 		add = (epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ? 2 : 1;
 
-		if (bar == test_reg_bar)
+		if (bar == test_reg_bar || bar == epf_test->doorbell_bar)
 			continue;
 
 		if (!!(epc_features->reserved_bar & (1 << bar)))
@@ -900,9 +923,14 @@ static int pci_epf_test_bind(struct pci_epf *epf)
 	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
 	const struct pci_epc_features *epc_features;
 	enum pci_barno test_reg_bar = BAR_0;
+	enum pci_barno doorbell_bar = NO_BAR;
 	struct pci_epc *epc = epf->epc;
 	bool linkup_notifier = false;
 	bool core_init_notifier = false;
+	struct pci_epf_test_reg *reg;
+	struct msi_msg *msg;
+	u64 doorbell_addr;
+	u32 align;
 
 	if (WARN_ON_ONCE(!epc))
 		return -EINVAL;
@@ -923,10 +951,39 @@ static int pci_epf_test_bind(struct pci_epf *epf)
 	epf_test->test_reg_bar = test_reg_bar;
 	epf_test->epc_features = epc_features;
 
+	align = epc_features->align;
+	align = align ? align : 128;
+
+	ret = pci_epf_alloc_doorbell(epf, 1);
+	if (!ret) {
+		msg = epf->msg;
+		doorbell_bar = pci_epc_get_next_free_bar(epc_features, test_reg_bar + 1);
+
+		if (doorbell_bar > 0) {
+			epf_test->doorbell_bar = doorbell_bar;
+			doorbell_addr = msg->address_hi;
+			doorbell_addr <<= 32;
+			doorbell_addr |= msg->address_lo;
+			epf->bar[doorbell_bar].phys_addr = round_down(doorbell_addr, align);
+			epf->bar[doorbell_bar].barno = doorbell_bar;
+			epf->bar[doorbell_bar].size = align;
+		} else {
+			pci_epf_free_doorbell(epf);
+		}
+	}
+
 	ret = pci_epf_test_alloc_space(epf);
 	if (ret)
 		return ret;
 
+	reg = epf_test->reg[test_reg_bar];
+	reg->magic |= FIELD_PREP(MAGIC_VERSION_MASK, 0x1);
+	if (doorbell_bar > 0) {
+		reg->doorbell_addr = doorbell_addr & (align - 1);
+		reg->doorbell_data = msg->data;
+		reg->doorbell_bar = doorbell_bar;
+	}
+
 	if (!core_init_notifier) {
 		ret = pci_epf_test_core_init(epf);
 		if (ret)
-- 
2.34.1