[PATCH v10 0/7] PCI: brcmstb: root port turns on sub-device power

v10 -- Bindings commit example: in comment, refer to bridge under
       controller node as a root port. (Pali)
    -- Bindings commit example: remove three properties that are not
       appropriate for a PCIe endpoint node. (Rob)

v9  -- Simplify where this mechanism works: instead of looking for
       regulators below every bridge, just look for them at the
       bridge under the root bus (root port).  Now there is no
       modification of portdrv_{pci,core}.c in this submission.
    -- Although Pali is working on support for probing native
       PCIe controller drivers, this work may take some time to
       implement and it still might not be able to accomodate
       our driver's requirements (e.g. vreg suspend/resume control).
    -- Move regulator suspend/resume control to Brcm RC driver.  It
       must reside there because (a) in order to know when to
       initiate linkup during resume and (b) to turn on the
       regulators before any config-space accesses occur.
    -- Commit message spelling, word choice (Bjorn, Krzysztof)
    -- Refactor a small commit that was ignoring a funcs' return
       values (Bjorn).
    -- Here is a summary of this mechanism:

       If:
           -- PCIe RC driver sets pci_ops {add,remove)_bus to
              pci_subdev_regulators_{add,remove}_bus during its probe.
           -- There is a DT node "RB" under the host bridge DT node.
           -- During the RC driver's pci_host_probe() the add_bus callback
              is invoked where (bus->parent && pci_is_root_bus(bus->parent)
              is true

       Then:
           -- A struct subdev_regulators structure will be allocated and
              assigned to bus->dev.driver_data.
           -- regulator_bulk_{get,enable}() will be invoked on &bus->dev
              and the former will search for and process any
              vpcie{12v,3v3,3v3aux}-supply properties that reside in node "RB".
           -- The regulators will be turned off/on for any unbind/bind operations.
           -- The regulators will be turned off/on for any suspend/resumes, but
              only if the RC driver handles this on its own.  This will appear
              in a later commit for the pcie-brcmstb.c driver.

v8  -- Only the two binding commits and the "Change brcm_phy_stop()" commit
       are unchanged.
    -- The code has been moved to portdrv_pci.c and bus.c.  The regulators   
       are placed in bus->dev.driver_data (bus->sysdata is already occupied
       by the Broadcom PCIe).  Two functions, pci_subdev_regulators_{add,remove}_bus()
       are created to turn the regulators on/off.  The pcie_portdriver also sets
       its pci_driver methods suspend and resume when the conditions are
       right for this feature.  (Robh for suggestions, although I probably
       erred in following them).
    -- Have the root complex return 0xffffffff on accesses even when
       the link is down and the HW doesn't support such accesses (PaliR).
    -- Just call devm_bulk_regulator_get() on standard supplies; don't
       bother pre-scanning the DT for them (MarkB).

v7  -- RobH suggested putting the "vpcixxx-supply" property under the
       bridge-node rather than the endpoint device node.  Also, he said to
       use the pci-ops add_bus/remove methods.  Doing so simplifies the
       code greatly and three commits were dropped.  Thanks!

    -- Rob also suggested (I think) having this patchset be a general
       feature which is activated by an OF property under the bridge node.
       I tried to do that but realized that our root complex driver
       controls the regulators with its dev_pm_ops and there is no way to
       transfer this control when using general mechanism.  Note that
       although the regulator core deals with suspend, our RC driver wants
       the right to sometimes to preclude this for WOL scenarios.

    -- One commit was added to change the response to the return value of
       the pci_ops add_bus() method.  Currently, an error causes a WARNING,
       a dev_err(...), and continues to return the child bus.  The
       modification was, for returning -ENOLINK only, to skip WARNING &
       dev_err() and return NULL.  This is necessary for our RC HW, as if
       the code continues on it will do a pci_read_config_dword() for the
       vendor/id, and our HW flags a CPU abort (instead of returning
       0xffffffff) when the is no pcie-link established.

       [NOTE: MarkB, I did not add one of your two "Reviewed-by"s
              because the commit had a decent amount of change.]

v6   -- Dropped the idea of a placeholder regulator
        property (brcm-ep-a-supply). (MarkB)
     -- device_initialize() now called once.  Two
        commits were added for this.  (GKH)
     -- In two cases, separated a single function 
        into two or more functions (MarkB)
     -- "(void)foo();" => "foo()".  Note that although
        foo() returns an int, in this instance it is being
	invoked within a function returning void, and foo()
	already executes a dev_err() on error. (MarkB)
     -- Added a commit to correct PCIe interrupts in YAML.
     -- Removed "device_type = "pci";" for the EP node
        in the YAML example.
     -- Updated the URL related to the voltage regulator
        names on GitHub.  Note that I added vpciev3v3aux.

v5 [NOTE: It has been a while since v4.  Sorry]
     -- See "PCI: allow for callback to prepare nascent subdev"
        commit message for the cornerstone of this patchset
        and the reasons behind it.  This is a new commit.
     -- The RC driver now looks into its DT children and
        turns on regulators for a sub-device, and this occurs
	prior to PCIe link as it must.
     -- Dropped commits not related to the focus of this patchset.

v4 [NOTE: I'm not sure this fixes RobH and MarkB constraints but I'd
          like to use this pullreq as a basis for future discussion.]
   [Commit: Add bindings for ...]
     -- Fix syntax error in YAML bindings example (RobH)
     -- {vpcie12v,vpcie3v3}-supply props are back in root complex DT node
        (I believe RobH said this was okay)
   [Commit: Add control of ..]
     -- Do not do global search for regulator; now we look specifically
        for the property {vpcie12v,vpcie3v3}-supply in the root complex
	DT node and then call devm_regulator_bulk_get() (MarkB)
     -- Use devm_regulator_bulk_get() (Bjorn)
     -- s/EP/slot0 device/ (Bjorn)
     -- Spelling, capitalization (Bjorn)
     -- Have brcm_phy_stop() return a void (Bjorn)
   [Commit: Do not turn off ...]
     -- Capitalization (Bjorn)
   [Commit: Check return value ...]
     -- Commit message content (Bjorn)
     -- Move 6/6 hunk to 2/6 where it belongs (Bjorn)
     -- Move the rest of 6/6 before all other commits (Bjorn)

v3 -- Driver now searches for EP DT subnode for any regulators to turn on.
      If present, these regulators have the property names
      "vpcie12v-supply" and "vpcie3v3-supply".  The existence of these
      regulators in the EP subnode are currently pending as a pullreq
      in pci-bus.yaml at
      https://github.com/devicetree-org/dt-schema/pull/54
      (MarkB, RobH).
   -- Check return of brcm_set_regulators() (Florian)
   -- Specify one regulator string per line for easier update (Florian)
   -- Author/Committer/Signoff email changed from that of V2 from
      'james.quinlan@broadcom.com' to 'jim2101024@gmail.com'.

v2 -- Use regulator bulk API rather than multiple calls (MarkB).

v1 -- Bindings are added for fixed regulators that may power the EP device.
   -- The brcmstb RC driver is modified to control these regulators
      during probe, suspend, and resume.
   -- 7216 type SOCs have additional error reporting HW and a
      panic handler is added to dump its info.
   -- A missing return value check is added.


Jim Quinlan (7):
  PCI: brcmstb: Fix function return value handling
  dt-bindings: PCI: Correct brcmstb interrupts, interrupt-map.
  dt-bindings: PCI: Add bindings for Brcmstb EP voltage regulators
  PCI: Add mechanism to turn on subdev regulators
  PCI: brcmstb: Split brcm_pcie_setup() into two funcs
  PCI: brcmstb: Add control of subdevice voltage regulators
  PCI: brcmstb: Do not turn off WOL regulators on suspend

 .../bindings/pci/brcm,stb-pcie.yaml           |  31 ++-
 drivers/pci/bus.c                             |  67 ++++++
 drivers/pci/controller/pcie-brcmstb.c         | 209 +++++++++++++++---
 drivers/pci/pci.h                             |   8 +
 4 files changed, 277 insertions(+), 38 deletions(-)


base-commit: ee1703cda8dc777e937dec172da55beaf1a74919
prerequisite-patch-id: 0905430e81a95900a1366916fe2940b848317a7c
prerequisite-patch-id: 710896210c50354d87f6025fe0bd1b89981138eb
prerequisite-patch-id: 97d3886cb911cb12ef3d514fdfff2a0ab11e8570
prerequisite-patch-id: 241f1e1878fc177d941f4982ca12779a29feb62b
prerequisite-patch-id: d856608825e2294297db5d7f88f8c180f3e5a1f2
prerequisite-patch-id: 92bcbc9772fb4d248157bcf35e799ac37be8ee45
prerequisite-patch-id: 6f4b1aac459bb54523ade0e87c04e9d6c45bd9f5
prerequisite-patch-id: 090ee7a3112a4ecb03805b23ed10e2c96b3b34ed
-- 
2.17.1


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Do at least a dev_err() on some calls to reset_control_rearm() and
brcm_phy_stop().  In some cases it may not make sense to return this error
value "above" as doing so will cause more trouble than is warranted.

Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
---
 drivers/pci/controller/pcie-brcmstb.c | 28 +++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 1fc7bd49a7ad..9ed79ddb6a83 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c

@@ -1146,11 +1146,23 @@ static int brcm_pcie_suspend(struct device *dev)
 	int ret;
 
 	brcm_pcie_turn_off(pcie);
-	ret = brcm_phy_stop(pcie);
-	reset_control_rearm(pcie->rescal);
+	/*
+	 * If brcm_phy_stop() returns an error, just dev_err(). If we
+	 * return the error it will cause the suspend to fail and this is a
+	 * forgivable offense that will probably be erased on resume.
+	 */
+	if (brcm_phy_stop(pcie))
+		dev_err(dev, "Could not stop phy for suspend\n");
+
+	ret = reset_control_rearm(pcie->rescal);
+	if (ret) {
+		dev_err(dev, "Could not rearm rescal reset\n");
+		return ret;
+	}
+
 	clk_disable_unprepare(pcie->clk);
 
-	return ret;
+	return 0;
 }
 
 static int brcm_pcie_resume(struct device *dev)

@@ -1161,7 +1173,9 @@ static int brcm_pcie_resume(struct device *dev)
 	int ret;
 
 	base = pcie->base;
-	clk_prepare_enable(pcie->clk);
+	ret = clk_prepare_enable(pcie->clk);
+	if (ret)
+		return ret;
 
 	ret = reset_control_reset(pcie->rescal);
 	if (ret)

@@ -1202,8 +1216,10 @@ static void __brcm_pcie_remove(struct brcm_pcie *pcie)
 {
 	brcm_msi_remove(pcie);
 	brcm_pcie_turn_off(pcie);
-	brcm_phy_stop(pcie);
-	reset_control_rearm(pcie->rescal);
+	if (brcm_phy_stop(pcie))
+		dev_err(pcie->dev, "Could not stop phy\n");
+	if (reset_control_rearm(pcie->rescal))
+		dev_err(pcie->dev, "Could not rearm rescal reset\n");
 	clk_disable_unprepare(pcie->clk);
 }
 

-- 
2.17.1


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On 12/9/21 1:13 PM, Jim Quinlan wrote:

Do at least a dev_err() on some calls to reset_control_rearm() and
brcm_phy_stop().  In some cases it may not make sense to return this error
value "above" as doing so will cause more trouble than is warranted.

Signed-off-by: Jim Quinlan <jim2101024@gmail.com>

Acked-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

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The "pcie" and "msi" interrupts were given the same interrupt when they are
actually different.  Interrupt-map only had the INTA entry; the INTB, INTC,
and INTD entries are added.

Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
---
 Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml b/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml
index 1fe102743f82..22f2ef446f18 100644
--- a/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml
+++ b/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml

@@ -143,11 +143,15 @@ examples:
                     #address-cells = <3>;
                     #size-cells = <2>;
                     #interrupt-cells = <1>;
-                    interrupts = <GIC_SPI 148 IRQ_TYPE_LEVEL_HIGH>,
+                    interrupts = <GIC_SPI 147 IRQ_TYPE_LEVEL_HIGH>,
                                  <GIC_SPI 148 IRQ_TYPE_LEVEL_HIGH>;
                     interrupt-names = "pcie", "msi";
                     interrupt-map-mask = <0x0 0x0 0x0 0x7>;
-                    interrupt-map = <0 0 0 1 &gicv2 GIC_SPI 143 IRQ_TYPE_LEVEL_HIGH>;
+                    interrupt-map = <0 0 0 1 &gicv2 GIC_SPI 143 IRQ_TYPE_LEVEL_HIGH
+                                     0 0 0 2 &gicv2 GIC_SPI 144 IRQ_TYPE_LEVEL_HIGH
+                                     0 0 0 3 &gicv2 GIC_SPI 145 IRQ_TYPE_LEVEL_HIGH
+                                     0 0 0 4 &gicv2 GIC_SPI 146 IRQ_TYPE_LEVEL_HIGH>;
+
                     msi-parent = <&pcie0>;
                     msi-controller;
                     ranges = <0x02000000 0x0 0xf8000000 0x6 0x00000000 0x0 0x04000000>;

-- 
2.17.1


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Add bindings for Brcmstb EP voltage regulators.  A new mechanism is to be
added to the Linux PCI subsystem that will allocate and turn on/off
regulators.  These are standard regulators -- vpcie12v, vpcie3v3, and
vpcie3v3aux -- placed in the DT in the bridge node under the host bridge
device.

The use of a regulator property in the pcie EP subnode such as
"vpcie12v-supply" depends on a pending pullreq to the pci-bus.yaml
file at

https://github.com/devicetree-org/dt-schema/pull/63

Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
---
 .../bindings/pci/brcm,stb-pcie.yaml           | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml b/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml
index 22f2ef446f18..3e3c8929c97c 100644
--- a/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml
+++ b/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml

@@ -159,5 +159,24 @@ examples:
                                  <0x42000000 0x1 0x80000000 0x3 0x00000000 0x0 0x80000000>;
                     brcm,enable-ssc;
                     brcm,scb-sizes =  <0x0000000080000000 0x0000000080000000>;
+
+                    /* PCIe bridge, Root Port */
+                    pci@0,0 {
+                            #address-cells = <3>;
+                            #size-cells = <2>;
+                            reg = <0x0 0x0 0x0 0x0 0x0>;
+                            compatible = "pciclass,0604";
+                            device_type = "pci";
+                            vpcie3v3-supply = <&vreg7>;
+                            ranges;
+
+                            /* PCIe endpoint */
+                            pci-ep@0,0 {
+                                    assigned-addresses =
+                                        <0x82010000 0x0 0xf8000000 0x6 0x00000000 0x0 0x2000>;
+                                    reg = <0x0 0x0 0x0 0x0 0x0>;
+                                    compatible = "pci14e4,1688";
+                            };
+                    };
             };
     };

-- 
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On Thu, Dec 09, 2021 at 04:14:01PM -0500, Jim Quinlan wrote:

Add bindings for Brcmstb EP voltage regulators.  A new mechanism is to be
added to the Linux PCI subsystem that will allocate and turn on/off
regulators.  These are standard regulators -- vpcie12v, vpcie3v3, and
vpcie3v3aux -- placed in the DT in the bridge node under the host bridge
device.

The use of a regulator property in the pcie EP subnode such as
"vpcie12v-supply" depends on a pending pullreq to the pci-bus.yaml
file at

https://github.com/devicetree-org/dt-schema/pull/63

Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
---
 .../bindings/pci/brcm,stb-pcie.yaml           | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

Reviewed-by: Rob Herring <robh@kernel.org>

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We need to take some code in brcm_pcie_setup() and put it in a new function
brcm_pcie_linkup().  In future commits the brcm_pcie_linkup() function will
be called indirectly by pci_host_probe() as opposed to the host driver
invoking it directly.

Some code that was executed after the PCIe linkup is now placed so that it
executes prior to linkup, since this code has to run prior to the
invocation of pci_host_probe().

Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
---
 drivers/pci/controller/pcie-brcmstb.c | 65 ++++++++++++++++-----------
 1 file changed, 39 insertions(+), 26 deletions(-)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 9ed79ddb6a83..5f373227aad6 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c

@@ -863,16 +863,9 @@ static inline int brcm_pcie_get_rc_bar2_size_and_offset(struct brcm_pcie *pcie,
 
 static int brcm_pcie_setup(struct brcm_pcie *pcie)
 {
-	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
 	u64 rc_bar2_offset, rc_bar2_size;
 	void __iomem *base = pcie->base;
-	struct device *dev = pcie->dev;
-	struct resource_entry *entry;
-	bool ssc_good = false;
-	struct resource *res;
-	int num_out_wins = 0;
-	u16 nlw, cls, lnksta;
-	int i, ret, memc;
+	int ret, memc;
 	u32 tmp, burst, aspm_support;
 
 	/* Reset the bridge */

@@ -957,6 +950,40 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
 	if (pcie->gen)
 		brcm_pcie_set_gen(pcie, pcie->gen);
 
+	/* Don't advertise L0s capability if 'aspm-no-l0s' */
+	aspm_support = PCIE_LINK_STATE_L1;
+	if (!of_property_read_bool(pcie->np, "aspm-no-l0s"))
+		aspm_support |= PCIE_LINK_STATE_L0S;
+	tmp = readl(base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
+	u32p_replace_bits(&tmp, aspm_support,
+		PCIE_RC_CFG_PRIV1_LINK_CAPABILITY_ASPM_SUPPORT_MASK);
+	writel(tmp, base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
+
+	/*
+	 * For config space accesses on the RC, show the right class for
+	 * a PCIe-PCIe bridge (the default setting is to be EP mode).
+	 */
+	tmp = readl(base + PCIE_RC_CFG_PRIV1_ID_VAL3);
+	u32p_replace_bits(&tmp, 0x060400,
+			  PCIE_RC_CFG_PRIV1_ID_VAL3_CLASS_CODE_MASK);
+	writel(tmp, base + PCIE_RC_CFG_PRIV1_ID_VAL3);
+
+	return 0;
+}
+
+static int brcm_pcie_linkup(struct brcm_pcie *pcie)
+{
+	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
+	struct device *dev = pcie->dev;
+	void __iomem *base = pcie->base;
+	struct resource_entry *entry;
+	struct resource *res;
+	int num_out_wins = 0;
+	u16 nlw, cls, lnksta;
+	bool ssc_good = false;
+	u32 tmp;
+	int ret, i;
+
 	/* Unassert the fundamental reset */
 	pcie->perst_set(pcie, 0);
 

@@ -994,24 +1021,6 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
 		num_out_wins++;
 	}
 
-	/* Don't advertise L0s capability if 'aspm-no-l0s' */
-	aspm_support = PCIE_LINK_STATE_L1;
-	if (!of_property_read_bool(pcie->np, "aspm-no-l0s"))
-		aspm_support |= PCIE_LINK_STATE_L0S;
-	tmp = readl(base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
-	u32p_replace_bits(&tmp, aspm_support,
-		PCIE_RC_CFG_PRIV1_LINK_CAPABILITY_ASPM_SUPPORT_MASK);
-	writel(tmp, base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
-
-	/*
-	 * For config space accesses on the RC, show the right class for
-	 * a PCIe-PCIe bridge (the default setting is to be EP mode).
-	 */
-	tmp = readl(base + PCIE_RC_CFG_PRIV1_ID_VAL3);
-	u32p_replace_bits(&tmp, 0x060400,
-			  PCIE_RC_CFG_PRIV1_ID_VAL3_CLASS_CODE_MASK);
-	writel(tmp, base + PCIE_RC_CFG_PRIV1_ID_VAL3);
-
 	if (pcie->ssc) {
 		ret = brcm_pcie_set_ssc(pcie);
 		if (ret == 0)

@@ -1200,6 +1209,10 @@ static int brcm_pcie_resume(struct device *dev)
 	if (ret)
 		goto err_reset;
 
+	ret = brcm_pcie_linkup(pcie);
+	if (ret)
+		goto err_reset;
+
 	if (pcie->msi)
 		brcm_msi_set_regs(pcie->msi);
 

-- 
2.17.1


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This Broadcom STB PCIe RC driver has one port and connects directly to one
device, be it a switch or an endpoint.  We want to be able to leverage
the recently added mechansim that allocates and turns on/off subdevice
regulators.

All that needs to be done is to put the regulator DT nodes in the bridge
below host and to set the pci_ops methods add_bus and remove_bus.

Note that the pci_subdev_regulators_add_bus() method is wrapped for two
reasons:

   1. To acheive linkup after the voltage regulators are turned on.

   2. If, in the case of an unsuccessful linkup, to redirect
      any PCIe accesses to subdevices, e.g. the scan for
      DEV/ID.  This redirection is needed because the Broadcom
      PCIe HW wil issue a CPU abort if such an access is made when
      there is no linkup.

Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
---
 drivers/pci/controller/pcie-brcmstb.c | 81 +++++++++++++++++++++++++--
 1 file changed, 77 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 5f373227aad6..9b4df253e79a 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c

@@ -191,6 +191,7 @@ static inline void brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie,
 static inline void brcm_pcie_perst_set_4908(struct brcm_pcie *pcie, u32 val);
 static inline void brcm_pcie_perst_set_7278(struct brcm_pcie *pcie, u32 val);
 static inline void brcm_pcie_perst_set_generic(struct brcm_pcie *pcie, u32 val);
+static int brcm_pcie_add_bus(struct pci_bus *bus);
 
 enum {
 	RGR1_SW_INIT_1,

@@ -295,6 +296,8 @@ struct brcm_pcie {
 	u32			hw_rev;
 	void			(*perst_set)(struct brcm_pcie *pcie, u32 val);
 	void			(*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val);
+	bool			refusal_mode;
+	struct subdev_regulators *sr;
 };
 
 /*

@@ -711,6 +714,18 @@ static void __iomem *brcm_pcie_map_conf(struct pci_bus *bus, unsigned int devfn,
 	/* Accesses to the RC go right to the RC registers if slot==0 */
 	if (pci_is_root_bus(bus))
 		return PCI_SLOT(devfn) ? NULL : base + where;
+	if (pcie->refusal_mode) {
+		/*
+		 * At this point we do not have link.  There will be a CPU
+		 * abort -- a quirk with this controller --if Linux tries
+		 * to read any config-space registers besides those
+		 * targeting the host bridge.  To prevent this we hijack
+		 * the address to point to a safe access that will return
+		 * 0xffffffff.
+		 */
+		writel(0xffffffff, base + PCIE_MISC_RC_BAR2_CONFIG_HI);
+		return base + PCIE_MISC_RC_BAR2_CONFIG_HI + (where & 0x3);
+	}
 
 	/* For devices, write to the config space index register */
 	idx = PCIE_ECAM_OFFSET(bus->number, devfn, 0);

@@ -722,6 +737,8 @@ static struct pci_ops brcm_pcie_ops = {
 	.map_bus = brcm_pcie_map_conf,
 	.read = pci_generic_config_read,
 	.write = pci_generic_config_write,
+	.add_bus = brcm_pcie_add_bus,
+	.remove_bus = pci_subdev_regulators_remove_bus,
 };
 
 static inline void brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie, u32 val)

@@ -1169,6 +1186,14 @@ static int brcm_pcie_suspend(struct device *dev)
 		return ret;
 	}
 
+	if (pcie->sr) {
+		ret = regulator_bulk_disable(pcie->sr->num_supplies, pcie->sr->supplies);
+		if (ret) {
+			dev_err(dev, "Could not turn off regulators\n");
+			reset_control_reset(pcie->rescal);
+			return ret;
+		}
+	}
 	clk_disable_unprepare(pcie->clk);
 
 	return 0;

@@ -1186,9 +1211,17 @@ static int brcm_pcie_resume(struct device *dev)
 	if (ret)
 		return ret;
 
+	if (pcie->sr) {
+		ret = regulator_bulk_enable(pcie->sr->num_supplies, pcie->sr->supplies);
+		if (ret) {
+			dev_err(dev, "Could not turn on regulators\n");
+			goto err_disable_clk;
+		}
+	}
+
 	ret = reset_control_reset(pcie->rescal);
 	if (ret)
-		goto err_disable_clk;
+		goto err_regulator;
 
 	ret = brcm_phy_start(pcie);
 	if (ret)

@@ -1220,6 +1253,8 @@ static int brcm_pcie_resume(struct device *dev)
 
 err_reset:
 	reset_control_rearm(pcie->rescal);
+err_regulator:
+	regulator_bulk_disable(pcie->sr->num_supplies, pcie->sr->supplies);
 err_disable_clk:
 	clk_disable_unprepare(pcie->clk);
 	return ret;

@@ -1258,6 +1293,34 @@ static const struct of_device_id brcm_pcie_match[] = {
 	{},
 };
 
+static int brcm_pcie_add_bus(struct pci_bus *bus)
+{
+	struct device *dev = &bus->dev;
+	struct brcm_pcie *pcie = (struct brcm_pcie *) bus->sysdata;
+	int ret;
+
+	if (!dev->of_node || !bus->parent || !pci_is_root_bus(bus->parent))
+		return 0;
+
+	ret = pci_subdev_regulators_add_bus(bus);
+	if (ret)
+		return ret;
+
+	/* Grab the regulators for suspend/resume */
+	pcie->sr = bus->dev.driver_data;
+
+	/*
+	 * If we have failed linkup there is no point to return an error as
+	 * currently it will cause a WARNING() from pci_alloc_child_bus().
+	 * We return 0 and turn on the "refusal_mode" so that any further
+	 * accesses to the pci_dev just get 0xffffffff
+	 */
+	if (brcm_pcie_linkup(pcie) != 0)
+		pcie->refusal_mode = true;
+
+	return 0;
+}
+
 static int brcm_pcie_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node, *msi_np;

@@ -1349,7 +1412,17 @@ static int brcm_pcie_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, pcie);
 
-	return pci_host_probe(bridge);
+	ret = pci_host_probe(bridge);
+	if (!ret && !brcm_pcie_link_up(pcie))
+		ret = -ENODEV;
+
+	if (ret) {
+		brcm_pcie_remove(pdev);
+		return ret;
+	}
+
+	return 0;
+
 fail:
 	__brcm_pcie_remove(pcie);
 	return ret;

@@ -1358,8 +1431,8 @@ static int brcm_pcie_probe(struct platform_device *pdev)
 MODULE_DEVICE_TABLE(of, brcm_pcie_match);
 
 static const struct dev_pm_ops brcm_pcie_pm_ops = {
-	.suspend = brcm_pcie_suspend,
-	.resume = brcm_pcie_resume,
+	.suspend_noirq = brcm_pcie_suspend,
+	.resume_noirq = brcm_pcie_resume,
 };
 
 static struct platform_driver brcm_pcie_driver = {

-- 
2.17.1


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If any downstream device can be awoken do not turn off
the regulators as the device will need them on.

Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
---
 drivers/pci/controller/pcie-brcmstb.c | 53 ++++++++++++++++++++++-----
 1 file changed, 44 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 9b4df253e79a..8e5cbf6850cd 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c

@@ -298,6 +298,7 @@ struct brcm_pcie {
 	void			(*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val);
 	bool			refusal_mode;
 	struct subdev_regulators *sr;
+	bool			ep_wakeup_capable;
 };
 
 /*

@@ -1166,9 +1167,21 @@ static void brcm_pcie_turn_off(struct brcm_pcie *pcie)
 	pcie->bridge_sw_init_set(pcie, 1);
 }
 
+static int pci_dev_may_wakeup(struct pci_dev *dev, void *data)
+{
+	bool *ret = data;
+
+	if (device_may_wakeup(&dev->dev)) {
+		*ret = true;
+		dev_info(&dev->dev, "disable cancelled for wake-up device\n");
+	}
+	return (int) *ret;
+}
+
 static int brcm_pcie_suspend(struct device *dev)
 {
 	struct brcm_pcie *pcie = dev_get_drvdata(dev);
+	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
 	int ret;
 
 	brcm_pcie_turn_off(pcie);

@@ -1187,11 +1200,22 @@ static int brcm_pcie_suspend(struct device *dev)
 	}
 
 	if (pcie->sr) {
-		ret = regulator_bulk_disable(pcie->sr->num_supplies, pcie->sr->supplies);
-		if (ret) {
-			dev_err(dev, "Could not turn off regulators\n");
-			reset_control_reset(pcie->rescal);
-			return ret;
+		/*
+		 * Now turn off the regulators, but if at least one
+		 * downstream device is enabled as a wake-up source, do not
+		 * turn off regulators.
+		 */
+		pcie->ep_wakeup_capable = false;
+		pci_walk_bus(bridge->bus, pci_dev_may_wakeup,
+			     &pcie->ep_wakeup_capable);
+		if (!pcie->ep_wakeup_capable) {
+			ret = regulator_bulk_disable(pcie->sr->num_supplies,
+						     pcie->sr->supplies);
+			if (ret) {
+				dev_err(dev, "Could not turn off regulators\n");
+				reset_control_reset(pcie->rescal);
+				return ret;
+			}
 		}
 	}
 	clk_disable_unprepare(pcie->clk);

@@ -1212,10 +1236,21 @@ static int brcm_pcie_resume(struct device *dev)
 		return ret;
 
 	if (pcie->sr) {
-		ret = regulator_bulk_enable(pcie->sr->num_supplies, pcie->sr->supplies);
-		if (ret) {
-			dev_err(dev, "Could not turn on regulators\n");
-			goto err_disable_clk;
+		if (pcie->ep_wakeup_capable) {
+			/*
+			 * We are resuming from a suspend.  In the suspend we
+			 * did not disable the power supplies, so there is
+			 * no need to enable them (and falsely increase their
+			 * usage count).
+			 */
+			pcie->ep_wakeup_capable = false;
+		} else {
+			ret = regulator_bulk_enable(pcie->sr->num_supplies,
+						    pcie->sr->supplies);
+			if (ret) {
+				dev_err(dev, "Could not turn on regulators\n");
+				goto err_disable_clk;
+			}
 		}
 	}
 

-- 
2.17.1


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On Thu, Dec 09, 2021 at 04:13:58PM -0500, Jim Quinlan wrote:

v10 -- Bindings commit example: in comment, refer to bridge under
       controller node as a root port. (Pali)
    -- Bindings commit example: remove three properties that are not
       appropriate for a PCIe endpoint node. (Rob)

v9  -- Simplify where this mechanism works: instead of looking for
       regulators below every bridge, just look for them at the
       bridge under the root bus (root port).  Now there is no
       modification of portdrv_{pci,core}.c in this submission.
    -- Although Pali is working on support for probing native
       PCIe controller drivers, this work may take some time to
       implement and it still might not be able to accomodate
       our driver's requirements (e.g. vreg suspend/resume control).
    -- Move regulator suspend/resume control to Brcm RC driver.  It
       must reside there because (a) in order to know when to
       initiate linkup during resume and (b) to turn on the
       regulators before any config-space accesses occur.

You now have a mixture of 'generic' add/remove_bus hooks and the host 
controller suspend/resume managing the regulators. I think long term, 
the portdrv is going to be the right place for all of this with some 
interface defined for link control. So I think this solution moves 
sideways rather than towards anything common.

Unfortunately, the only leverage maintainers have to get folks to care 
about any refactoring is to reject features. We're lucky to find anyone 
to test refactoring when posted if done independently. There's a long 
list of commits of PCI hosts that I've broken to prove that. So it's 
up to Lorenzo and Bjorn on what they want to do here.

Rob

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On 12/10/21 10:44 AM, Rob Herring wrote:

On Thu, Dec 09, 2021 at 04:13:58PM -0500, Jim Quinlan wrote:

quoted

v10 -- Bindings commit example: in comment, refer to bridge under
       controller node as a root port. (Pali)
    -- Bindings commit example: remove three properties that are not
       appropriate for a PCIe endpoint node. (Rob)

v9  -- Simplify where this mechanism works: instead of looking for
       regulators below every bridge, just look for them at the
       bridge under the root bus (root port).  Now there is no
       modification of portdrv_{pci,core}.c in this submission.
    -- Although Pali is working on support for probing native
       PCIe controller drivers, this work may take some time to
       implement and it still might not be able to accomodate
       our driver's requirements (e.g. vreg suspend/resume control).
    -- Move regulator suspend/resume control to Brcm RC driver.  It
       must reside there because (a) in order to know when to
       initiate linkup during resume and (b) to turn on the
       regulators before any config-space accesses occur.

You now have a mixture of 'generic' add/remove_bus hooks and the host 
controller suspend/resume managing the regulators. I think long term, 
the portdrv is going to be the right place for all of this with some 
interface defined for link control. So I think this solution moves 
sideways rather than towards anything common.

Unfortunately, the only leverage maintainers have to get folks to care 
about any refactoring is to reject features. We're lucky to find anyone 
to test refactoring when posted if done independently. There's a long 
list of commits of PCI hosts that I've broken to prove that. So it's 
up to Lorenzo and Bjorn on what they want to do here.

After version 10, it would seem pretty clear that we are still very much
committed to and interested in getting that set merged and do it the
most acceptable way possible. Common code with a single user is always a
little bit of a grey area to me as it tends to be developed to cater for
the specific needs of that single user, so the entire common aspect is
debatable. I suppose as long as we have the binding right, the code can
change at will.

Not trying to coerce Bjorn and Lorenzo into accepting these patches if
they don't feel comfortable, but what about getting it included so we
can sort of move on from that topic for a little bit (as we have other
PCIe changes coming in, supporting additional chips etc.) and we work
with Pali on a common solution and ensure it works on our pcie-brcmstb.c
based devices? We are not going to vanish and not come back looking at this.
-- 
Florian

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On Fri, Dec 10, 2021 at 12:31:10PM -0800, Florian Fainelli wrote:

On 12/10/21 10:44 AM, Rob Herring wrote:

quoted

On Thu, Dec 09, 2021 at 04:13:58PM -0500, Jim Quinlan wrote:

quoted

v10 -- Bindings commit example: in comment, refer to bridge under
       controller node as a root port. (Pali)
    -- Bindings commit example: remove three properties that are not
       appropriate for a PCIe endpoint node. (Rob)

v9  -- Simplify where this mechanism works: instead of looking for
       regulators below every bridge, just look for them at the
       bridge under the root bus (root port).  Now there is no
       modification of portdrv_{pci,core}.c in this submission.
    -- Although Pali is working on support for probing native
       PCIe controller drivers, this work may take some time to
       implement and it still might not be able to accomodate
       our driver's requirements (e.g. vreg suspend/resume control).
    -- Move regulator suspend/resume control to Brcm RC driver.  It
       must reside there because (a) in order to know when to
       initiate linkup during resume and (b) to turn on the
       regulators before any config-space accesses occur.

You now have a mixture of 'generic' add/remove_bus hooks and the host 
controller suspend/resume managing the regulators. I think long term, 
the portdrv is going to be the right place for all of this with some 
interface defined for link control. So I think this solution moves 
sideways rather than towards anything common.

Unfortunately, the only leverage maintainers have to get folks to care 
about any refactoring is to reject features. We're lucky to find anyone 
to test refactoring when posted if done independently. There's a long 
list of commits of PCI hosts that I've broken to prove that. So it's 
up to Lorenzo and Bjorn on what they want to do here.

After version 10, it would seem pretty clear that we are still very much
committed to and interested in getting that set merged and do it the
most acceptable way possible. Common code with a single user is always a
little bit of a grey area to me as it tends to be developed to cater for
the specific needs of that single user, so the entire common aspect is
debatable. I suppose as long as we have the binding right, the code can
change at will.

Not trying to coerce Bjorn and Lorenzo into accepting these patches if
they don't feel comfortable, but what about getting it included so we
can sort of move on from that topic for a little bit (as we have other
PCIe changes coming in, supporting additional chips etc.) and we work
with Pali on a common solution and ensure it works on our pcie-brcmstb.c
based devices? We are not going to vanish and not come back looking at this.

Sorry for being late on reviewing this set. I agree with both of you.

I don't think Bjorn had a chance to have a look at patch (4) now I am
delegating it to him; I am not very keen on adding functionality to PCI
core where it is still a question whether it can be reused by other
drivers (forgive me if I missed some details on previous review
versions).

Is it possible to keep patch (4) brcmstb specific (ie keep the code
out of PCI core for now), we then merge this series and help Pali
implement a generic version based on Rob's suggestion ?

Just let me know please, thanks.

Lorenzo

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On Tue, Jan 4, 2022 at 9:18 AM Lorenzo Pieralisi
[off-list ref] wrote:

On Fri, Dec 10, 2021 at 12:31:10PM -0800, Florian Fainelli wrote:

quoted

On 12/10/21 10:44 AM, Rob Herring wrote:

quoted

On Thu, Dec 09, 2021 at 04:13:58PM -0500, Jim Quinlan wrote:

quoted

v10 -- Bindings commit example: in comment, refer to bridge under
       controller node as a root port. (Pali)
    -- Bindings commit example: remove three properties that are not
       appropriate for a PCIe endpoint node. (Rob)

v9  -- Simplify where this mechanism works: instead of looking for
       regulators below every bridge, just look for them at the
       bridge under the root bus (root port).  Now there is no
       modification of portdrv_{pci,core}.c in this submission.
    -- Although Pali is working on support for probing native
       PCIe controller drivers, this work may take some time to
       implement and it still might not be able to accomodate
       our driver's requirements (e.g. vreg suspend/resume control).
    -- Move regulator suspend/resume control to Brcm RC driver.  It
       must reside there because (a) in order to know when to
       initiate linkup during resume and (b) to turn on the
       regulators before any config-space accesses occur.

You now have a mixture of 'generic' add/remove_bus hooks and the host
controller suspend/resume managing the regulators. I think long term,
the portdrv is going to be the right place for all of this with some
interface defined for link control. So I think this solution moves
sideways rather than towards anything common.

Unfortunately, the only leverage maintainers have to get folks to care
about any refactoring is to reject features. We're lucky to find anyone
to test refactoring when posted if done independently. There's a long
list of commits of PCI hosts that I've broken to prove that. So it's
up to Lorenzo and Bjorn on what they want to do here.

After version 10, it would seem pretty clear that we are still very much
committed to and interested in getting that set merged and do it the
most acceptable way possible. Common code with a single user is always a
little bit of a grey area to me as it tends to be developed to cater for
the specific needs of that single user, so the entire common aspect is
debatable. I suppose as long as we have the binding right, the code can
change at will.

Not trying to coerce Bjorn and Lorenzo into accepting these patches if
they don't feel comfortable, but what about getting it included so we
can sort of move on from that topic for a little bit (as we have other
PCIe changes coming in, supporting additional chips etc.) and we work
with Pali on a common solution and ensure it works on our pcie-brcmstb.c
based devices? We are not going to vanish and not come back looking at this.

Sorry for being late on reviewing this set. I agree with both of you.

I don't think Bjorn had a chance to have a look at patch (4) now I am
delegating it to him; I am not very keen on adding functionality to PCI
core where it is still a question whether it can be reused by other
drivers (forgive me if I missed some details on previous review
versions).

Is it possible to keep patch (4) brcmstb specific (ie keep the code
out of PCI core for now), we then merge this series and help Pali
implement a generic version based on Rob's suggestion ?

Just let me know please, thanks.

Hi Lorenzo,

That sounds good to me.  Pullreq coming tomorrow.

Thanks,
Jim Quinlan
Broadcom STB

Lorenzo

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