From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To: "Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Rob Herring" <robh@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Kishon Vijay Abraham I" <kishon@kernel.org>,
"Thierry Reding" <thierry.reding@gmail.com>,
"Jonathan Hunter" <jonathanh@nvidia.com>,
"Jingoo Han" <jingoohan1@gmail.com>,
"Gustavo Pimentel" <gustavo.pimentel@synopsys.com>
Cc: linux-pci@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-kernel@vger.kernel.org, mhi@lists.linux.dev,
linux-tegra@vger.kernel.org,
Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Subject: [PATCH 07/11] PCI: dwc: ep: Add a generic dw_pcie_ep_linkdown() API to handle Link Down event
Date: Thu, 14 Mar 2024 20:53:46 +0530 [thread overview]
Message-ID: <20240314-pci-epf-rework-v1-7-6134e6c1d491@linaro.org> (raw)
In-Reply-To: <20240314-pci-epf-rework-v1-0-6134e6c1d491@linaro.org>
As per the PCIe base spec r5.0, section 5.2, Link Down event can happen
under any of the following circumstances:
1. Fundamental/Hot reset
2. Link disable transmission by upstream component
3. Moving from L2/L3 to L0
In those cases, Link Down causes some non-sticky DWC registers to loose the
state (like REBAR, etc...). So the drivers need to reinitialize them to
function properly once the link comes back again.
This is not a problem for drivers supporting PERST# IRQ, since they can
reinitialize the registers in the PERST# IRQ callback. But for the drivers
not supporting PERST#, there is no way they can reinitialize the registers
other than relying on Link Down IRQ received when the link goes down. So
let's add a DWC generic API dw_pcie_ep_linkdown() that reinitializes the
non-sticky registers and also notifies the EPF drivers about link going
down.
This API can also be used by the drivers supporting PERST# to handle the
scenario (2) mentioned above.
NOTE: For the sake of code organization, move the dw_pcie_ep_linkup()
definition just above dw_pcie_ep_linkdown().
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
drivers/pci/controller/dwc/pcie-designware-ep.c | 93 ++++++++++++++++---------
drivers/pci/controller/dwc/pcie-designware.h | 5 ++
2 files changed, 67 insertions(+), 31 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 3893a8c1a11c..5451057ca74b 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -14,18 +14,6 @@
#include <linux/pci-epc.h>
#include <linux/pci-epf.h>
-/**
- * dw_pcie_ep_linkup - Notify EPF drivers about link up event
- * @ep: DWC EP device
- */
-void dw_pcie_ep_linkup(struct dw_pcie_ep *ep)
-{
- struct pci_epc *epc = ep->epc;
-
- pci_epc_linkup(epc);
-}
-EXPORT_SYMBOL_GPL(dw_pcie_ep_linkup);
-
/**
* dw_pcie_ep_init_notify - Notify EPF drivers about EPC initialization
* complete
@@ -672,6 +660,29 @@ static unsigned int dw_pcie_ep_find_ext_capability(struct dw_pcie *pci, int cap)
return 0;
}
+static void dw_pcie_ep_init_non_sticky_registers(struct dw_pcie *pci)
+{
+ unsigned int offset;
+ unsigned int nbars;
+ u32 reg, i;
+
+ offset = dw_pcie_ep_find_ext_capability(pci, PCI_EXT_CAP_ID_REBAR);
+
+ dw_pcie_dbi_ro_wr_en(pci);
+
+ if (offset) {
+ reg = dw_pcie_readl_dbi(pci, offset + PCI_REBAR_CTRL);
+ nbars = (reg & PCI_REBAR_CTRL_NBAR_MASK) >>
+ PCI_REBAR_CTRL_NBAR_SHIFT;
+
+ for (i = 0; i < nbars; i++, offset += PCI_REBAR_CTRL)
+ dw_pcie_writel_dbi(pci, offset + PCI_REBAR_CAP, 0x0);
+ }
+
+ dw_pcie_setup(pci);
+ dw_pcie_dbi_ro_wr_dis(pci);
+}
+
/**
* dw_pcie_ep_init_registers - Initialize DWC EP specific registers
* @ep: DWC EP device
@@ -686,13 +697,11 @@ int dw_pcie_ep_init_registers(struct dw_pcie_ep *ep)
struct dw_pcie_ep_func *ep_func;
struct device *dev = pci->dev;
struct pci_epc *epc = ep->epc;
- unsigned int offset, ptm_cap_base;
- unsigned int nbars;
+ u32 ptm_cap_base, reg;
u8 hdr_type;
u8 func_no;
- int i, ret;
void *addr;
- u32 reg;
+ int ret;
hdr_type = dw_pcie_readb_dbi(pci, PCI_HEADER_TYPE) &
PCI_HEADER_TYPE_MASK;
@@ -755,20 +764,8 @@ int dw_pcie_ep_init_registers(struct dw_pcie_ep *ep)
if (ep->ops->init)
ep->ops->init(ep);
- offset = dw_pcie_ep_find_ext_capability(pci, PCI_EXT_CAP_ID_REBAR);
ptm_cap_base = dw_pcie_ep_find_ext_capability(pci, PCI_EXT_CAP_ID_PTM);
- dw_pcie_dbi_ro_wr_en(pci);
-
- if (offset) {
- reg = dw_pcie_readl_dbi(pci, offset + PCI_REBAR_CTRL);
- nbars = (reg & PCI_REBAR_CTRL_NBAR_MASK) >>
- PCI_REBAR_CTRL_NBAR_SHIFT;
-
- for (i = 0; i < nbars; i++, offset += PCI_REBAR_CTRL)
- dw_pcie_writel_dbi(pci, offset + PCI_REBAR_CAP, 0x0);
- }
-
/*
* PTM responder capability can be disabled only after disabling
* PTM root capability.
@@ -785,9 +782,6 @@ int dw_pcie_ep_init_registers(struct dw_pcie_ep *ep)
dw_pcie_dbi_ro_wr_dis(pci);
}
- dw_pcie_setup(pci);
- dw_pcie_dbi_ro_wr_dis(pci);
-
return 0;
err_remove_edma:
@@ -797,6 +791,43 @@ int dw_pcie_ep_init_registers(struct dw_pcie_ep *ep)
}
EXPORT_SYMBOL_GPL(dw_pcie_ep_init_registers);
+/**
+ * dw_pcie_ep_linkup - Notify EPF drivers about Link Up event
+ * @ep: DWC EP device
+ */
+void dw_pcie_ep_linkup(struct dw_pcie_ep *ep)
+{
+ struct pci_epc *epc = ep->epc;
+
+ pci_epc_linkup(epc);
+}
+EXPORT_SYMBOL_GPL(dw_pcie_ep_linkup);
+
+/**
+ * dw_pcie_ep_linkdown - Notify EPF drivers about Link Down event
+ * @ep: DWC EP device
+ *
+ * Non-sticky registers are also initialized before sending the notification to
+ * the EPF drivers. This is needed since the registers need to be initialized
+ * before the link comes back again.
+ */
+void dw_pcie_ep_linkdown(struct dw_pcie_ep *ep)
+{
+ struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
+ struct pci_epc *epc = ep->epc;
+
+ /*
+ * Initialize the non-sticky DWC registers as they would've reset post
+ * Link Down. This is specifically needed for drivers not supporting
+ * PERST# as they have no way to reinitialize the registers before the
+ * link comes back again.
+ */
+ dw_pcie_ep_init_non_sticky_registers(pci);
+
+ pci_epc_linkdown(epc);
+}
+EXPORT_SYMBOL_GPL(dw_pcie_ep_linkdown);
+
/**
* dw_pcie_ep_init - Initialize the endpoint device
* @ep: DWC EP device
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index f8e5431a207b..152969545b0a 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -668,6 +668,7 @@ static inline void __iomem *dw_pcie_own_conf_map_bus(struct pci_bus *bus,
#ifdef CONFIG_PCIE_DW_EP
void dw_pcie_ep_linkup(struct dw_pcie_ep *ep);
+void dw_pcie_ep_linkdown(struct dw_pcie_ep *ep);
int dw_pcie_ep_init(struct dw_pcie_ep *ep);
int dw_pcie_ep_init_registers(struct dw_pcie_ep *ep);
void dw_pcie_ep_init_notify(struct dw_pcie_ep *ep);
@@ -688,6 +689,10 @@ static inline void dw_pcie_ep_linkup(struct dw_pcie_ep *ep)
{
}
+static inline void dw_pcie_ep_linkdown(struct dw_pcie_ep *ep)
+{
+}
+
static inline int dw_pcie_ep_init(struct dw_pcie_ep *ep)
{
return 0;
--
2.25.1
next prev parent reply other threads:[~2024-03-14 15:24 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-14 15:23 [PATCH 00/11] PCI: endpoint: Make host reboot handling more robust Manivannan Sadhasivam
2024-03-14 15:23 ` [PATCH 01/11] PCI: qcom-ep: Disable resources unconditionally during PERST# assert Manivannan Sadhasivam
2024-03-22 16:08 ` Niklas Cassel
2024-03-26 7:44 ` Manivannan Sadhasivam
2024-03-26 10:24 ` Niklas Cassel
2024-03-26 11:10 ` Manivannan Sadhasivam
2024-03-26 13:47 ` Niklas Cassel
2024-03-26 13:55 ` Manivannan Sadhasivam
2024-03-26 10:37 ` Niklas Cassel
2024-03-14 15:23 ` [PATCH 02/11] PCI: endpoint: Decouple EPC and PCIe bus specific events Manivannan Sadhasivam
2024-03-22 16:08 ` Niklas Cassel
2024-03-26 7:49 ` Manivannan Sadhasivam
2024-03-14 15:23 ` [PATCH 03/11] PCI: endpoint: Rename core_init() callback in 'struct pci_epc_event_ops' to init() Manivannan Sadhasivam
2024-03-22 16:08 ` Niklas Cassel
2024-03-26 7:56 ` Manivannan Sadhasivam
2024-03-14 15:23 ` [PATCH 04/11] PCI: epf-test: Refactor pci_epf_test_unbind() function Manivannan Sadhasivam
2024-03-22 16:09 ` Niklas Cassel
2024-03-26 7:58 ` Manivannan Sadhasivam
2024-03-14 15:23 ` [PATCH 05/11] PCI: epf-{mhi/test}: Move DMA initialization to EPC init callback Manivannan Sadhasivam
2024-03-22 16:10 ` Niklas Cassel
2024-03-26 8:26 ` Manivannan Sadhasivam
2024-03-26 11:05 ` Niklas Cassel
2024-03-26 14:27 ` Niklas Cassel
2024-03-27 6:20 ` Manivannan Sadhasivam
2024-03-27 6:18 ` Manivannan Sadhasivam
2024-03-27 11:39 ` Niklas Cassel
2024-03-28 18:42 ` Vinod Koul
2024-04-04 8:44 ` Niklas Cassel
2024-04-22 7:55 ` Manivannan Sadhasivam
2024-04-22 9:30 ` Niklas Cassel
2024-03-14 15:23 ` [PATCH 06/11] PCI: endpoint: Introduce EPC 'deinit' event and notify the EPF drivers Manivannan Sadhasivam
2024-03-22 16:10 ` Niklas Cassel
2024-03-26 8:31 ` Manivannan Sadhasivam
2024-03-14 15:23 ` Manivannan Sadhasivam [this message]
2024-03-22 16:10 ` [PATCH 07/11] PCI: dwc: ep: Add a generic dw_pcie_ep_linkdown() API to handle Link Down event Niklas Cassel
2024-03-27 18:06 ` Niklas Cassel
2024-04-01 16:34 ` Manivannan Sadhasivam
2024-03-14 15:23 ` [PATCH 08/11] PCI: qcom-ep: Use the " Manivannan Sadhasivam
2024-03-14 15:23 ` [PATCH 09/11] PCI: epf-test: Handle " Manivannan Sadhasivam
2024-03-22 16:10 ` Niklas Cassel
2024-03-14 15:23 ` [PATCH 10/11] PCI: qcom-ep: Rework {start/stop}_link() callbacks implementation Manivannan Sadhasivam
2024-03-22 16:10 ` Niklas Cassel
2024-03-26 8:33 ` Manivannan Sadhasivam
2024-03-14 15:23 ` [PATCH 11/11] PCI: tegra194: " Manivannan Sadhasivam
2024-03-22 16:11 ` Niklas Cassel
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