* [PATCH] PCI: imx6: Separate PERST# assertion from core reset functions
@ 2026-03-06 3:04 Sherry Sun
2026-03-06 3:09 ` Hongxing Zhu
2026-03-26 17:13 ` Manivannan Sadhasivam
0 siblings, 2 replies; 3+ messages in thread
From: Sherry Sun @ 2026-03-06 3:04 UTC (permalink / raw)
To: hongxing.zhu, l.stach, Frank.Li, bhelgaas, lpieralisi,
kwilczynski, mani, robh, s.hauer, festevam
Cc: imx, kernel, linux-pci, linux-arm-kernel, linux-kernel
The imx_pcie_assert_core_reset() and imx_pcie_deassert_core_reset()
functions are primarily intended to reset the RC controller itself, not
the remote PCIe endpoint devices. However, the PERST# GPIO control was
previously embedded within these functions, which conflates two distinct
reset operations.
Move the PERST# GPIO handling into a dedicated function
imx_pcie_assert_perst(). This makes the code more maintainable and
prepares for parsing the reset-gpios property according to the new
Root Port DT binding in subsequent patches.
No functional change is intended.
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
---
drivers/pci/controller/dwc/pci-imx6.c | 29 +++++++++++++++++----------
1 file changed, 18 insertions(+), 11 deletions(-)
diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index ba6e7c7ee625..d80d3be28ee5 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -901,9 +901,6 @@ static void imx_pcie_assert_core_reset(struct imx_pcie *imx_pcie)
if (imx_pcie->drvdata->core_reset)
imx_pcie->drvdata->core_reset(imx_pcie, true);
-
- /* Some boards don't have PCIe reset GPIO. */
- gpiod_set_value_cansleep(imx_pcie->reset_gpiod, 1);
}
static void imx_pcie_deassert_core_reset(struct imx_pcie *imx_pcie)
@@ -912,14 +909,6 @@ static void imx_pcie_deassert_core_reset(struct imx_pcie *imx_pcie)
if (imx_pcie->drvdata->core_reset)
imx_pcie->drvdata->core_reset(imx_pcie, false);
-
- /* Some boards don't have PCIe reset GPIO. */
- if (imx_pcie->reset_gpiod) {
- msleep(100);
- gpiod_set_value_cansleep(imx_pcie->reset_gpiod, 0);
- /* Wait for 100ms after PERST# deassertion (PCIe r5.0, 6.6.1) */
- msleep(100);
- }
}
static int imx_pcie_wait_for_speed_change(struct imx_pcie *imx_pcie)
@@ -1231,6 +1220,19 @@ static void imx_pcie_disable_device(struct pci_host_bridge *bridge,
imx_pcie_remove_lut(imx_pcie, pci_dev_id(pdev));
}
+static void imx_pcie_assert_perst(struct imx_pcie *imx_pcie, bool assert)
+{
+ if (assert) {
+ gpiod_set_value_cansleep(imx_pcie->reset_gpiod, 1);
+ } else {
+ if (imx_pcie->reset_gpiod) {
+ msleep(PCIE_T_PVPERL_MS);
+ gpiod_set_value_cansleep(imx_pcie->reset_gpiod, 0);
+ msleep(PCIE_RESET_CONFIG_WAIT_MS);
+ }
+ }
+}
+
static int imx_pcie_host_init(struct dw_pcie_rp *pp)
{
struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
@@ -1253,6 +1255,7 @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp)
}
imx_pcie_assert_core_reset(imx_pcie);
+ imx_pcie_assert_perst(imx_pcie, true);
if (imx_pcie->drvdata->init_phy)
imx_pcie->drvdata->init_phy(imx_pcie);
@@ -1291,6 +1294,7 @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp)
imx_pcie_ltssm_disable(dev);
imx_pcie_deassert_core_reset(imx_pcie);
+ imx_pcie_assert_perst(imx_pcie, false);
if (imx_pcie->drvdata->wait_pll_lock) {
ret = imx_pcie->drvdata->wait_pll_lock(imx_pcie);
@@ -1587,6 +1591,7 @@ static int imx_pcie_suspend_noirq(struct device *dev)
* clock which saves some power.
*/
imx_pcie_assert_core_reset(imx_pcie);
+ imx_pcie_assert_perst(imx_pcie, true);
imx_pcie->drvdata->enable_ref_clk(imx_pcie, false);
} else {
return dw_pcie_suspend_noirq(imx_pcie->pci);
@@ -1608,6 +1613,7 @@ static int imx_pcie_resume_noirq(struct device *dev)
if (ret)
return ret;
imx_pcie_deassert_core_reset(imx_pcie);
+ imx_pcie_assert_perst(imx_pcie, false);
/*
* Using PCIE_TEST_PD seems to disable MSI and powers down the
@@ -1845,6 +1851,7 @@ static void imx_pcie_shutdown(struct platform_device *pdev)
/* bring down link, so bootloader gets clean state in case of reboot */
imx_pcie_assert_core_reset(imx_pcie);
+ imx_pcie_assert_perst(imx_pcie, true);
}
static const struct imx_pcie_drvdata drvdata[] = {
--
2.37.1
^ permalink raw reply [flat|nested] 3+ messages in thread* RE: [PATCH] PCI: imx6: Separate PERST# assertion from core reset functions
2026-03-06 3:04 [PATCH] PCI: imx6: Separate PERST# assertion from core reset functions Sherry Sun
@ 2026-03-06 3:09 ` Hongxing Zhu
2026-03-26 17:13 ` Manivannan Sadhasivam
1 sibling, 0 replies; 3+ messages in thread
From: Hongxing Zhu @ 2026-03-06 3:09 UTC (permalink / raw)
To: Sherry Sun, l.stach, Frank Li, bhelgaas, lpieralisi, kwilczynski,
mani, robh, s.hauer, festevam
Cc: imx, kernel, linux-pci, linux-arm-kernel, linux-kernel
> -----Original Message-----
> From: Sherry Sun <sherry.sun@nxp.com>
> Sent: 2026年3月6日 11:05
> To: Hongxing Zhu <hongxing.zhu@nxp.com>; l.stach@pengutronix.de; Frank
> Li <frank.li@nxp.com>; bhelgaas@google.com; lpieralisi@kernel.org;
> kwilczynski@kernel.org; mani@kernel.org; robh@kernel.org;
> s.hauer@pengutronix.de; festevam@gmail.com
> Cc: imx@lists.linux.dev; kernel@pengutronix.de; linux-pci@vger.kernel.org;
> linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org
> Subject: [PATCH] PCI: imx6: Separate PERST# assertion from core reset
> functions
>
> The imx_pcie_assert_core_reset() and imx_pcie_deassert_core_reset()
> functions are primarily intended to reset the RC controller itself, not the
> remote PCIe endpoint devices. However, the PERST# GPIO control was
> previously embedded within these functions, which conflates two distinct
> reset operations.
>
> Move the PERST# GPIO handling into a dedicated function
> imx_pcie_assert_perst(). This makes the code more maintainable and
> prepares for parsing the reset-gpios property according to the new Root
> Port DT binding in subsequent patches.
>
> No functional change is intended.
>
> Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Reviewed-by: Richard Zhu <hongxing.zhu@nxp.com>
Best Regards
Richard Zhu
> ---
> drivers/pci/controller/dwc/pci-imx6.c | 29 +++++++++++++++++----------
> 1 file changed, 18 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> b/drivers/pci/controller/dwc/pci-imx6.c
> index ba6e7c7ee625..d80d3be28ee5 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -901,9 +901,6 @@ static void imx_pcie_assert_core_reset(struct
> imx_pcie *imx_pcie)
>
> if (imx_pcie->drvdata->core_reset)
> imx_pcie->drvdata->core_reset(imx_pcie, true);
> -
> - /* Some boards don't have PCIe reset GPIO. */
> - gpiod_set_value_cansleep(imx_pcie->reset_gpiod, 1);
> }
>
> static void imx_pcie_deassert_core_reset(struct imx_pcie *imx_pcie) @@
> -912,14 +909,6 @@ static void imx_pcie_deassert_core_reset(struct
> imx_pcie *imx_pcie)
>
> if (imx_pcie->drvdata->core_reset)
> imx_pcie->drvdata->core_reset(imx_pcie, false);
> -
> - /* Some boards don't have PCIe reset GPIO. */
> - if (imx_pcie->reset_gpiod) {
> - msleep(100);
> - gpiod_set_value_cansleep(imx_pcie->reset_gpiod, 0);
> - /* Wait for 100ms after PERST# deassertion (PCIe r5.0, 6.6.1) */
> - msleep(100);
> - }
> }
>
> static int imx_pcie_wait_for_speed_change(struct imx_pcie *imx_pcie) @@
> -1231,6 +1220,19 @@ static void imx_pcie_disable_device(struct
> pci_host_bridge *bridge,
> imx_pcie_remove_lut(imx_pcie, pci_dev_id(pdev)); }
>
> +static void imx_pcie_assert_perst(struct imx_pcie *imx_pcie, bool
> +assert) {
> + if (assert) {
> + gpiod_set_value_cansleep(imx_pcie->reset_gpiod, 1);
> + } else {
> + if (imx_pcie->reset_gpiod) {
> + msleep(PCIE_T_PVPERL_MS);
> + gpiod_set_value_cansleep(imx_pcie->reset_gpiod, 0);
> + msleep(PCIE_RESET_CONFIG_WAIT_MS);
> + }
> + }
> +}
> +
> static int imx_pcie_host_init(struct dw_pcie_rp *pp) {
> struct dw_pcie *pci = to_dw_pcie_from_pp(pp); @@ -1253,6 +1255,7
> @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp)
> }
>
> imx_pcie_assert_core_reset(imx_pcie);
> + imx_pcie_assert_perst(imx_pcie, true);
>
> if (imx_pcie->drvdata->init_phy)
> imx_pcie->drvdata->init_phy(imx_pcie);
> @@ -1291,6 +1294,7 @@ static int imx_pcie_host_init(struct dw_pcie_rp
> *pp)
> imx_pcie_ltssm_disable(dev);
>
> imx_pcie_deassert_core_reset(imx_pcie);
> + imx_pcie_assert_perst(imx_pcie, false);
>
> if (imx_pcie->drvdata->wait_pll_lock) {
> ret = imx_pcie->drvdata->wait_pll_lock(imx_pcie);
> @@ -1587,6 +1591,7 @@ static int imx_pcie_suspend_noirq(struct device
> *dev)
> * clock which saves some power.
> */
> imx_pcie_assert_core_reset(imx_pcie);
> + imx_pcie_assert_perst(imx_pcie, true);
> imx_pcie->drvdata->enable_ref_clk(imx_pcie, false);
> } else {
> return dw_pcie_suspend_noirq(imx_pcie->pci);
> @@ -1608,6 +1613,7 @@ static int imx_pcie_resume_noirq(struct device
> *dev)
> if (ret)
> return ret;
> imx_pcie_deassert_core_reset(imx_pcie);
> + imx_pcie_assert_perst(imx_pcie, false);
>
> /*
> * Using PCIE_TEST_PD seems to disable MSI and powers down the
> @@ -1845,6 +1851,7 @@ static void imx_pcie_shutdown(struct
> platform_device *pdev)
>
> /* bring down link, so bootloader gets clean state in case of reboot */
> imx_pcie_assert_core_reset(imx_pcie);
> + imx_pcie_assert_perst(imx_pcie, true);
> }
>
> static const struct imx_pcie_drvdata drvdata[] = {
> --
> 2.37.1
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] PCI: imx6: Separate PERST# assertion from core reset functions
2026-03-06 3:04 [PATCH] PCI: imx6: Separate PERST# assertion from core reset functions Sherry Sun
2026-03-06 3:09 ` Hongxing Zhu
@ 2026-03-26 17:13 ` Manivannan Sadhasivam
1 sibling, 0 replies; 3+ messages in thread
From: Manivannan Sadhasivam @ 2026-03-26 17:13 UTC (permalink / raw)
To: hongxing.zhu, l.stach, Frank.Li, bhelgaas, lpieralisi,
kwilczynski, robh, s.hauer, festevam, Sherry Sun
Cc: imx, kernel, linux-pci, linux-arm-kernel, linux-kernel
On Fri, 06 Mar 2026 11:04:56 +0800, Sherry Sun wrote:
> The imx_pcie_assert_core_reset() and imx_pcie_deassert_core_reset()
> functions are primarily intended to reset the RC controller itself, not
> the remote PCIe endpoint devices. However, the PERST# GPIO control was
> previously embedded within these functions, which conflates two distinct
> reset operations.
>
> Move the PERST# GPIO handling into a dedicated function
> imx_pcie_assert_perst(). This makes the code more maintainable and
> prepares for parsing the reset-gpios property according to the new
> Root Port DT binding in subsequent patches.
>
> [...]
Applied, thanks!
[1/1] PCI: imx6: Separate PERST# assertion from core reset functions
commit: 180ea823bb45eb71dd5ed0dc0b78633accd21096
Best regards,
--
Manivannan Sadhasivam <mani@kernel.org>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2026-03-26 17:13 UTC | newest]
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2026-03-06 3:04 [PATCH] PCI: imx6: Separate PERST# assertion from core reset functions Sherry Sun
2026-03-06 3:09 ` Hongxing Zhu
2026-03-26 17:13 ` Manivannan Sadhasivam
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