[PATCH v12 8/8] PCI: endpoint: Remove "core_init_notifier" flag

Manivannan Sadhasivam
2024-03-27T09:16:19Z

"core_init_notifier" flag is set by the glue drivers requiring refclk from
the host to complete the DWC core initialization. Also, those drivers will
send a notification to the EPF drivers once the initialization is fully
completed using the pci_epc_init_notify() API. Only then, the EPF drivers
will start functioning.

For the rest of the drivers generating refclk locally, EPF drivers will
start functioning post binding with them. EPF drivers rely on the
'core_init_notifier' flag to differentiate between the drivers.
Unfortunately, this creates two different flows for the EPF drivers.

So to avoid that, let's get rid of the "core_init_notifier" flag and follow
a single initialization flow for the EPF drivers. This is done by calling
the dw_pcie_ep_init_notify() from all glue drivers after the completion of
dw_pcie_ep_init_registers() API. This will allow all the glue drivers to
send the notification to the EPF drivers once the initialization is fully
completed.

Only difference here is that, the drivers requiring refclk from host will
send the notification once refclk is received, while others will send it
during probe time itself.

But this also requires the EPC core driver to deliver the notification
after EPF driver bind. Because, the glue driver can send the notification
before the EPF drivers bind() and in those cases the EPF drivers will miss
the event. To accommodate this, EPC core is now caching the state of the
EPC initialization in 'init_complete' flag and pci-ep-cfs driver sends the
notification to EPF drivers based on that after each EPF driver bind.

Tested-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
drivers/pci/controller/cadence/pcie-cadence-ep.c | 2 ++
drivers/pci/controller/dwc/pci-dra7xx.c | 2 ++
drivers/pci/controller/dwc/pci-imx6.c | 2 ++
drivers/pci/controller/dwc/pci-keystone.c | 2 ++
drivers/pci/controller/dwc/pci-layerscape-ep.c | 2 ++
drivers/pci/controller/dwc/pcie-artpec6.c | 2 ++
drivers/pci/controller/dwc/pcie-designware-ep.c | 1 +
drivers/pci/controller/dwc/pcie-designware-plat.c | 2 ++
drivers/pci/controller/dwc/pcie-keembay.c | 2 ++
drivers/pci/controller/dwc/pcie-qcom-ep.c | 1 -
drivers/pci/controller/dwc/pcie-rcar-gen4.c | 2 ++
drivers/pci/controller/dwc/pcie-tegra194.c | 1 -
drivers/pci/controller/dwc/pcie-uniphier-ep.c | 2 ++
drivers/pci/controller/pcie-rcar-ep.c | 2 ++
drivers/pci/controller/pcie-rockchip-ep.c | 2 ++
drivers/pci/endpoint/functions/pci-epf-test.c | 18 +++++-------------
drivers/pci/endpoint/pci-ep-cfs.c | 9 +++++++++
drivers/pci/endpoint/pci-epc-core.c | 22 ++++++++++++++++++++++
include/linux/pci-epc.h | 7 ++++---
19 files changed, 65 insertions(+), 18 deletions(-)

diff --git a/drivers/pci/controller/cadence/pcie-cadence-ep.c b/drivers/pci/controller/cadence/pcie-cadence-ep.c
index 81c50dc64da9..55c42ca2b777 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-ep.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-ep.c
@@ -746,6 +746,8 @@ int cdns_pcie_ep_setup(struct cdns_pcie_ep *ep)

spin_lock_init(&ep->lock);

+ pci_epc_init_notify(epc);
+
return 0;

free_epc_mem:
diff --git a/drivers/pci/controller/dwc/pci-dra7xx.c b/drivers/pci/controller/dwc/pci-dra7xx.c
index 395042b29ffc..d2d17d37d3e0 100644
--- a/drivers/pci/controller/dwc/pci-dra7xx.c
+++ b/drivers/pci/controller/dwc/pci-dra7xx.c
@@ -474,6 +474,8 @@ static int dra7xx_add_pcie_ep(struct dra7xx_pcie *dra7xx,
return ret;
}

+ dw_pcie_ep_init_notify(ep);
+
return 0;
}

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 8d28ecc381bc..917c69edee1d 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -1131,6 +1131,8 @@ static int imx6_add_pcie_ep(struct imx6_pcie *imx6_pcie,
return ret;
}

+ dw_pcie_ep_init_notify(ep);
+
/* Start LTSSM. */
imx6_pcie_ltssm_enable(dev);

diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
index 81ebac520650..d3a7d14ee685 100644
--- a/drivers/pci/controller/dwc/pci-keystone.c
+++ b/drivers/pci/controller/dwc/pci-keystone.c
@@ -1293,6 +1293,8 @@ static int ks_pcie_probe(struct platform_device *pdev)
goto err_ep_init;
}

+ dw_pcie_ep_init_notify(&pci->ep);
+
break;
default:
dev_err(dev, "INVALID device type %d\n", mode);
diff --git a/drivers/pci/controller/dwc/pci-layerscape-ep.c b/drivers/pci/controller/dwc/pci-layerscape-ep.c
index 9eb2233e3d7f..7dde6d5fa4d8 100644
--- a/drivers/pci/controller/dwc/pci-layerscape-ep.c
+++ b/drivers/pci/controller/dwc/pci-layerscape-ep.c
@@ -286,6 +286,8 @@ static int __init ls_pcie_ep_probe(struct platform_device *pdev)
return ret;
}

+ dw_pcie_ep_init_notify(&pci->ep);
+
return ls_pcie_ep_interrupt_init(pcie, pdev);
}

diff --git a/drivers/pci/controller/dwc/pcie-artpec6.c b/drivers/pci/controller/dwc/pcie-artpec6.c
index a6095561db4a..a4630b92489b 100644
--- a/drivers/pci/controller/dwc/pcie-artpec6.c
+++ b/drivers/pci/controller/dwc/pcie-artpec6.c
@@ -452,6 +452,8 @@ static int artpec6_pcie_probe(struct platform_device *pdev)
return ret;
}

+ dw_pcie_ep_init_notify(&pci->ep);
+
break;
default:
dev_err(dev, "INVALID device type %d\n", artpec6_pcie->mode);
diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 2063cf2049e5..47391d7d3a73 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -632,6 +632,7 @@ void dw_pcie_ep_cleanup(struct dw_pcie_ep *ep)
struct dw_pcie *pci = to_dw_pcie_from_ep(ep);

dw_pcie_edma_remove(pci);
+ ep->epc->init_complete = false;
}
EXPORT_SYMBOL_GPL(dw_pcie_ep_cleanup);

diff --git a/drivers/pci/controller/dwc/pcie-designware-plat.c b/drivers/pci/controller/dwc/pcie-designware-plat.c
index ca9b22e654cd..8490c5d6ff9f 100644
--- a/drivers/pci/controller/dwc/pcie-designware-plat.c
+++ b/drivers/pci/controller/dwc/pcie-designware-plat.c
@@ -154,6 +154,8 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
dw_pcie_ep_deinit(&pci->ep);
}

+ dw_pcie_ep_init_notify(&pci->ep);
+
break;
default:
dev_err(dev, "INVALID device type %d\n", dw_plat_pcie->mode);
diff --git a/drivers/pci/controller/dwc/pcie-keembay.c b/drivers/pci/controller/dwc/pcie-keembay.c
index b2556dbcffb5..98bbc83182b4 100644
--- a/drivers/pci/controller/dwc/pcie-keembay.c
+++ b/drivers/pci/controller/dwc/pcie-keembay.c
@@ -442,6 +442,8 @@ static int keembay_pcie_probe(struct platform_device *pdev)
return ret;
}

+ dw_pcie_ep_init_notify(&pci->ep);
+
break;
default:
dev_err(dev, "Invalid device type %d\n", pcie->mode);
diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c
index 3697b4a944cc..2fb8c15e7a91 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-ep.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
@@ -775,7 +775,6 @@ static void qcom_pcie_ep_init_debugfs(struct qcom_pcie_ep *pcie_ep)

static const struct pci_epc_features qcom_pcie_epc_features = {
.linkup_notifier = true,
- .core_init_notifier = true,
.msi_capable = true,
.msix_capable = false,
.align = SZ_4K,
diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
index e155a905fb4f..cfeccc2f9ee1 100644
--- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
+++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
@@ -437,6 +437,8 @@ static int rcar_gen4_add_dw_pcie_ep(struct rcar_gen4_pcie *rcar)
rcar_gen4_pcie_ep_deinit(rcar);
}

+ dw_pcie_ep_init_notify(ep);
+
return ret;
}

diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index db043f579fbe..ddc23602eca7 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -2006,7 +2006,6 @@ static int tegra_pcie_ep_raise_irq(struct dw_pcie_ep *ep, u8 func_no,

static const struct pci_epc_features tegra_pcie_epc_features = {
.linkup_notifier = true,
- .core_init_notifier = true,
.msi_capable = false,
.msix_capable = false,
.bar[BAR_0] = { .type = BAR_FIXED, .fixed_size = SZ_1M,
diff --git a/drivers/pci/controller/dwc/pcie-uniphier-ep.c b/drivers/pci/controller/dwc/pcie-uniphier-ep.c
index 0e5e7344de48..a2b844268e28 100644
--- a/drivers/pci/controller/dwc/pcie-uniphier-ep.c
+++ b/drivers/pci/controller/dwc/pcie-uniphier-ep.c
@@ -410,6 +410,8 @@ static int uniphier_pcie_ep_probe(struct platform_device *pdev)
return ret;
}

+ dw_pcie_ep_init_notify(&priv->pci.ep);
+
return 0;
}

diff --git a/drivers/pci/controller/pcie-rcar-ep.c b/drivers/pci/controller/pcie-rcar-ep.c
index 05967c6c0b42..047e2cef5afc 100644
--- a/drivers/pci/controller/pcie-rcar-ep.c
+++ b/drivers/pci/controller/pcie-rcar-ep.c
@@ -542,6 +542,8 @@ static int rcar_pcie_ep_probe(struct platform_device *pdev)
goto err_pm_put;
}

+ pci_epc_init_notify(epc);
+
return 0;

err_pm_put:
diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index c9046e97a1d2..8613df8184df 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -609,6 +609,8 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
rockchip_pcie_write(rockchip, PCIE_CLIENT_CONF_ENABLE,
PCIE_CLIENT_CONFIG);

+ pci_epc_init_notify(epc);
+
return 0;
err_epc_mem_exit:
pci_epc_mem_exit(epc);
diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index cd4ffb39dcdc..212fc303fb63 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -753,6 +753,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
const struct pci_epc_features *epc_features;
struct pci_epc *epc = epf->epc;
struct device *dev = &epf->dev;
+ bool linkup_notifier = false;
bool msix_capable = false;
bool msi_capable = true;
int ret;
@@ -795,6 +796,10 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
}
}

+ linkup_notifier = epc_features->linkup_notifier;
+ if (!linkup_notifier)
+ queue_work(kpcitest_workqueue, &epf_test->cmd_handler.work);
+
return 0;
}

@@ -890,8 +895,6 @@ static int pci_epf_test_bind(struct pci_epf *epf)
const struct pci_epc_features *epc_features;
enum pci_barno test_reg_bar = BAR_0;
struct pci_epc *epc = epf->epc;
- bool linkup_notifier = false;
- bool core_init_notifier = false;

if (WARN_ON_ONCE(!epc))
return -EINVAL;
@@ -902,8 +905,6 @@ static int pci_epf_test_bind(struct pci_epf *epf)
return -EOPNOTSUPP;
}

- linkup_notifier = epc_features->linkup_notifier;
- core_init_notifier = epc_features->core_init_notifier;
test_reg_bar = pci_epc_get_first_free_bar(epc_features);
if (test_reg_bar < 0)
return -EINVAL;
@@ -916,21 +917,12 @@ static int pci_epf_test_bind(struct pci_epf *epf)
if (ret)
return ret;

- if (!core_init_notifier) {
- ret = pci_epf_test_core_init(epf);
- if (ret)
- return ret;
- }
-
epf_test->dma_supported = true;

ret = pci_epf_test_init_dma_chan(epf_test);
if (ret)
epf_test->dma_supported = false;

- if (!linkup_notifier && !core_init_notifier)
- queue_work(kpcitest_workqueue, &epf_test->cmd_handler.work);
-
return 0;
}

diff --git a/drivers/pci/endpoint/pci-ep-cfs.c b/drivers/pci/endpoint/pci-ep-cfs.c
index 0ea64e24ed61..3b21e28f9b59 100644
--- a/drivers/pci/endpoint/pci-ep-cfs.c
+++ b/drivers/pci/endpoint/pci-ep-cfs.c
@@ -64,6 +64,9 @@ static int pci_secondary_epc_epf_link(struct config_item *epf_item,
return ret;
}

+ /* Send any pending EPC initialization complete to the EPF driver */
+ pci_epc_notify_pending_init(epc, epf);
+
return 0;
}

@@ -125,6 +128,9 @@ static int pci_primary_epc_epf_link(struct config_item *epf_item,
return ret;
}

+ /* Send any pending EPC initialization complete to the EPF driver */
+ pci_epc_notify_pending_init(epc, epf);
+
return 0;
}

@@ -230,6 +236,9 @@ static int pci_epc_epf_link(struct config_item *epc_item,
return ret;
}

+ /* Send any pending EPC initialization complete to the EPF driver */
+ pci_epc_notify_pending_init(epc, epf);
+
return 0;
}

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index da3fc0795b0b..47d27ec7439d 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -748,10 +748,32 @@ void pci_epc_init_notify(struct pci_epc *epc)
epf->event_ops->core_init(epf);
mutex_unlock(&epf->lock);
}
+ epc->init_complete = true;
mutex_unlock(&epc->list_lock);
}
EXPORT_SYMBOL_GPL(pci_epc_init_notify);

+/**
+ * pci_epc_notify_pending_init() - Notify the pending EPC device initialization
+ * complete to the EPF device
+ * @epc: the EPC device whose core initialization is pending to be notified
+ * @epf: the EPF device to be notified
+ *
+ * Invoke to notify the pending EPC device initialization complete to the EPF
+ * device. This is used to deliver the notification if the EPC initialization
+ * got completed before the EPF driver bind.
+ */
+void pci_epc_notify_pending_init(struct pci_epc *epc, struct pci_epf *epf)
+{
+ if (epc->init_complete) {
+ mutex_lock(&epf->lock);
+ if (epf->event_ops && epf->event_ops->core_init)
+ epf->event_ops->core_init(epf);
+ mutex_unlock(&epf->lock);
+ }
+}
+EXPORT_SYMBOL_GPL(pci_epc_notify_pending_init);
+
/**
* pci_epc_bme_notify() - Notify the EPF device that the EPC device has received
* the BME event from the Root complex
diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index cc2f70d061c8..acc5f96161fe 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -128,6 +128,8 @@ struct pci_epc_mem {
* @group: configfs group representing the PCI EPC device
* @lock: mutex to protect pci_epc ops
* @function_num_map: bitmap to manage physical function number
+ * @init_complete: flag to indicate whether the EPC initialization is complete
+ * or not
*/
struct pci_epc {
struct device dev;
@@ -143,6 +145,7 @@ struct pci_epc {
/* mutex to protect against concurrent access of EP controller */
struct mutex lock;
unsigned long function_num_map;
+ bool init_complete;
};

/**
@@ -179,8 +182,6 @@ struct pci_epc_bar_desc {
/**
* struct pci_epc_features - features supported by a EPC device per function
* @linkup_notifier: indicate if the EPC device can notify EPF driver on link up
- * @core_init_notifier: indicate cores that can notify about their availability
- * for initialization
* @msi_capable: indicate if the endpoint function has MSI capability
* @msix_capable: indicate if the endpoint function has MSI-X capability
* @bar: array specifying the hardware description for each BAR
@@ -188,7 +189,6 @@ struct pci_epc_bar_desc {
*/
struct pci_epc_features {
unsigned int linkup_notifier : 1;
- unsigned int core_init_notifier : 1;
unsigned int msi_capable : 1;
unsigned int msix_capable : 1;
struct pci_epc_bar_desc bar[PCI_STD_NUM_BARS];
@@ -225,6 +225,7 @@ int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf,
void pci_epc_linkup(struct pci_epc *epc);
void pci_epc_linkdown(struct pci_epc *epc);
void pci_epc_init_notify(struct pci_epc *epc);
+void pci_epc_notify_pending_init(struct pci_epc *epc, struct pci_epf *epf);
void pci_epc_bme_notify(struct pci_epc *epc);
void pci_epc_remove_epf(struct pci_epc *epc, struct pci_epf *epf,
enum pci_epc_interface_type type);

--
2.25.1