[PATCH v6 0/3] ata: ahci_brcm: Fix use of BCM7216 reset controller

[PATCH v6 0/3] ata: ahci_brcm: Fix use of BCM7216 reset controller

[Jim Quinlan]

v6 -- Added new commit which adds a missing function to the reset API.
      This fixes 557acb3d2cd9 and should be destined for linux stable.

v5 -- Improved (I hope) commit description (Bjorn).
   -- Rnamed error labels (Krzyszt).
   -- Fixed typos.

v4 -- does not rely on a pending commit, unlike v3.

v3 -- discard commit from v2; instead rely on the new function
      reset_control_rearm provided in a recent commit [1] applied
      to reset/next.
   -- New commit to correct pcie-brcmstb.c usage of a reset controller
      to use reset/rearm verses deassert/assert.

v2 -- refactor rescal-reset driver to implement assert/deassert rather than
      reset because the reset call only fires once per lifetime and we need
      to reset after every resume from S2 or S3.
   -- Split the use of "ahci" and "rescal" controllers in separate fields
      to keep things simple.

v1 -- original

Jim Quinlan (3):
  reset: add missing empty function reset_control_rearm()
  ata: ahci_brcm: Fix use of BCM7216 reset controller
  PCI: brcmstb: Use reset/rearm instead of deassert/assert

 drivers/ata/ahci_brcm.c               | 46 +++++++++++++--------------
 drivers/pci/controller/pcie-brcmstb.c | 19 +++++++----
 include/linux/reset.h                 |  5 +++
 3 files changed, 41 insertions(+), 29 deletions(-)

-- 
2.17.1


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[PATCH v6 3/3] PCI: brcmstb: Use reset/rearm instead of deassert/assert

[Jim Quinlan]

The Broadcom STB PCIe RC uses a reset control "rescal" for certain chips.
The "rescal" implements a "pulse reset" so using assert/deassert is wrong
for this device.  Instead, we use reset/rearm.  We need to use rearm so
that we can reset it after a suspend/resume cycle; w/o using "rearm", the
"rescal" device will only ever fire once.

Of course for suspend/resume to work we also need to put the reset/rearm
calls in the suspend and resume routines.

Fixes: 740d6c3708a9 ("PCI: brcmstb: Add control of rescal reset")
Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/pci/controller/pcie-brcmstb.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index e330e6811f0b..3b35d629035e 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -1148,6 +1148,7 @@ static int brcm_pcie_suspend(struct device *dev)
 
 	brcm_pcie_turn_off(pcie);
 	ret = brcm_phy_stop(pcie);
+	reset_control_rearm(pcie->rescal);
 	clk_disable_unprepare(pcie->clk);
 
 	return ret;
@@ -1163,9 +1164,13 @@ static int brcm_pcie_resume(struct device *dev)
 	base = pcie->base;
 	clk_prepare_enable(pcie->clk);
 
+	ret = reset_control_reset(pcie->rescal);
+	if (ret)
+		goto err_disable_clk;
+
 	ret = brcm_phy_start(pcie);
 	if (ret)
-		goto err;
+		goto err_reset;
 
 	/* Take bridge out of reset so we can access the SERDES reg */
 	pcie->bridge_sw_init_set(pcie, 0);
@@ -1180,14 +1185,16 @@ static int brcm_pcie_resume(struct device *dev)
 
 	ret = brcm_pcie_setup(pcie);
 	if (ret)
-		goto err;
+		goto err_reset;
 
 	if (pcie->msi)
 		brcm_msi_set_regs(pcie->msi);
 
 	return 0;
 
-err:
+err_reset:
+	reset_control_rearm(pcie->rescal);
+err_disable_clk:
 	clk_disable_unprepare(pcie->clk);
 	return ret;
 }
@@ -1197,7 +1204,7 @@ static void __brcm_pcie_remove(struct brcm_pcie *pcie)
 	brcm_msi_remove(pcie);
 	brcm_pcie_turn_off(pcie);
 	brcm_phy_stop(pcie);
-	reset_control_assert(pcie->rescal);
+	reset_control_rearm(pcie->rescal);
 	clk_disable_unprepare(pcie->clk);
 }
 
@@ -1278,13 +1285,13 @@ static int brcm_pcie_probe(struct platform_device *pdev)
 		return PTR_ERR(pcie->perst_reset);
 	}
 
-	ret = reset_control_deassert(pcie->rescal);
+	ret = reset_control_reset(pcie->rescal);
 	if (ret)
 		dev_err(&pdev->dev, "failed to deassert 'rescal'\n");
 
 	ret = brcm_phy_start(pcie);
 	if (ret) {
-		reset_control_assert(pcie->rescal);
+		reset_control_rearm(pcie->rescal);
 		clk_disable_unprepare(pcie->clk);
 		return ret;
 	}
-- 
2.17.1


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Re: [PATCH v6 0/3] ata: ahci_brcm: Fix use of BCM7216 reset controller

[Bjorn Helgaas]

On Fri, Apr 30, 2021 at 11:21:53AM -0400, Jim Quinlan wrote:
> v6 -- Added new commit which adds a missing function to the reset API.
>       This fixes 557acb3d2cd9 and should be destined for linux stable.
> 
> v5 -- Improved (I hope) commit description (Bjorn).
>    -- Rnamed error labels (Krzyszt).
>    -- Fixed typos.
> 
> v4 -- does not rely on a pending commit, unlike v3.
> 
> v3 -- discard commit from v2; instead rely on the new function
>       reset_control_rearm provided in a recent commit [1] applied
>       to reset/next.
>    -- New commit to correct pcie-brcmstb.c usage of a reset controller
>       to use reset/rearm verses deassert/assert.
> 
> v2 -- refactor rescal-reset driver to implement assert/deassert rather than
>       reset because the reset call only fires once per lifetime and we need
>       to reset after every resume from S2 or S3.
>    -- Split the use of "ahci" and "rescal" controllers in separate fields
>       to keep things simple.
> 
> v1 -- original
> 
> Jim Quinlan (3):
>   reset: add missing empty function reset_control_rearm()
>   ata: ahci_brcm: Fix use of BCM7216 reset controller
>   PCI: brcmstb: Use reset/rearm instead of deassert/assert
> 
>  drivers/ata/ahci_brcm.c               | 46 +++++++++++++--------------
>  drivers/pci/controller/pcie-brcmstb.c | 19 +++++++----
>  include/linux/reset.h                 |  5 +++
>  3 files changed, 41 insertions(+), 29 deletions(-)

I provisionally applied these to my pci/brcmstb branch for v5.13.

I carried forward Jens' ack on "ata: ahci_brcm: Fix use of BCM7216
reset controller" since the patch is identical to the v5 version that
he acked.

I'm hoping to get an ack from Philipp for the reset.h change.

Bjorn

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