[PATCH v3 3/3] PCI: imx6: Add support for i.MX8MQ

[PATCH v3 3/3] PCI: imx6: Add support for i.MX8MQ

[Andrey Smirnov]

Add code needed to support i.MX8MQ variant.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Leonard Crestez <leonard.crestez@nxp.com>
Cc: "A.s. Dong" <aisheng.dong@nxp.com>
Cc: Richard Zhu <hongxing.zhu@nxp.com>
Cc: Rob Herring <robh@kernel.org>
Cc: devicetree@vger.kernel.org
Cc: linux-imx@nxp.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org
---
 .../bindings/pci/fsl,imx6q-pcie.txt           |  6 +-
 drivers/pci/controller/dwc/Kconfig            |  4 +-
 drivers/pci/controller/dwc/pci-imx6.c         | 82 ++++++++++++++++++-
 3 files changed, 87 insertions(+), 5 deletions(-)

diff --git a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
index d514c1f2365f..1a10c313e8d7 100644
--- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
+++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
@@ -9,6 +9,7 @@ Required properties:
 	- "fsl,imx6sx-pcie",
 	- "fsl,imx6qp-pcie"
 	- "fsl,imx7d-pcie"
+	- "fsl,imx8mq-pcie"
 - reg: base address and length of the PCIe controller
 - interrupts: A list of interrupt outputs of the controller. Must contain an
   entry for each entry in the interrupt-names property.
@@ -45,7 +46,7 @@ Additional required properties for imx6sx-pcie:
   PCIE_PHY power domains
 - power-domain-names: Must be "pcie", "pcie_phy"
 
-Additional required properties for imx7d-pcie:
+Additional required properties for imx7d-pcie and imx8mq-pcie:
 - power-domains: Must be set to a phandle pointing to PCIE_PHY power domain
 - resets: Must contain phandles to PCIe-related reset lines exposed by SRC
   IP block
@@ -54,6 +55,9 @@ Additional required properties for imx7d-pcie:
 	       - "apps"
 	       - "turnoff"
 
+Additional required properties for imx8mq-pcie:
+- fsl,controller-id: Logical ID of a given PCIE controller. PCIE1 is 0, PCIE2 is 1;
+
 Example:
 
 	pcie@01000000 {
diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
index 6aafec3fad00..83ea318ad989 100644
--- a/drivers/pci/controller/dwc/Kconfig
+++ b/drivers/pci/controller/dwc/Kconfig
@@ -89,8 +89,8 @@ config PCI_EXYNOS
 	select PCIE_DW_HOST
 
 config PCI_IMX6
-	bool "Freescale i.MX6/7 PCIe controller"
-	depends on SOC_IMX6Q || SOC_IMX7D || (ARM && COMPILE_TEST)
+	bool "Freescale i.MX6/7/8 PCIe controller"
+	depends on SOC_IMX6Q || SOC_IMX7D || (ARM64 && ARCH_MXC) || ((ARM || ARM64) && COMPILE_TEST)
 	depends on PCI_MSI_IRQ_DOMAIN
 	select PCIE_DW_HOST
 
diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index caa05104b90b..d71680920155 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -8,6 +8,7 @@
  * Author: Sean Cross <xobs@kosagi.com>
  */
 
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/gpio.h>
@@ -32,6 +33,11 @@
 
 #include "pcie-designware.h"
 
+#define IMX8MQ_GPR_PCIE_REF_USE_PAD		BIT(9)
+#define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN	BIT(10)
+#define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE	BIT(11)
+#define IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE	GENMASK(11, 8)
+
 #define to_imx6_pcie(x)	dev_get_drvdata((x)->dev)
 
 enum imx6_pcie_variants {
@@ -39,6 +45,7 @@ enum imx6_pcie_variants {
 	IMX6SX,
 	IMX6QP,
 	IMX7D,
+	IMX8MQ,
 };
 
 #define IMX6_PCIE_FLAG_IMX6_PHY		BIT(0)
@@ -57,6 +64,7 @@ struct imx6_pcie {
 	struct clk		*pcie_inbound_axi;
 	struct clk		*pcie;
 	struct regmap		*iomuxc_gpr;
+	u32			controller_id;
 	struct reset_control	*pciephy_reset;
 	struct reset_control	*apps_reset;
 	struct reset_control	*turnoff_reset;
@@ -275,6 +283,7 @@ static void imx6_pcie_reset_phy(struct imx6_pcie *imx6_pcie)
 	pcie_phy_write(imx6_pcie, PHY_RX_OVRD_IN_LO, tmp);
 }
 
+#ifdef CONFIG_ARM
 /*  Added for PCI abort handling */
 static int imx6q_pcie_abort_handler(unsigned long addr,
 		unsigned int fsr, struct pt_regs *regs)
@@ -308,6 +317,7 @@ static int imx6q_pcie_abort_handler(unsigned long addr,
 
 	return 1;
 }
+#endif
 
 static int imx6_pcie_attach_pd(struct device *dev)
 {
@@ -352,6 +362,7 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
 
 	switch (imx6_pcie->drvdata->variant) {
 	case IMX7D:
+	case IMX8MQ:
 		reset_control_assert(imx6_pcie->pciephy_reset);
 		reset_control_assert(imx6_pcie->apps_reset);
 		break;
@@ -390,6 +401,7 @@ static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
 {
 	struct dw_pcie *pci = imx6_pcie->pci;
 	struct device *dev = pci->dev;
+	unsigned int offset;
 	int ret = 0;
 
 	switch (imx6_pcie->drvdata->variant) {
@@ -420,6 +432,29 @@ static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
 		break;
 	case IMX7D:
 		break;
+	case IMX8MQ:
+		switch (imx6_pcie->controller_id) {
+		case 0:
+			offset = IOMUXC_GPR14;
+			break;
+		case 1:
+			offset = IOMUXC_GPR16;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		/*
+		 * Set the over ride low and enabled
+		 * make sure that REF_CLK is turned on.
+		 */
+		regmap_update_bits(imx6_pcie->iomuxc_gpr, offset,
+				   IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE,
+				   0);
+		regmap_update_bits(imx6_pcie->iomuxc_gpr, offset,
+				   IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN,
+				   IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN);
+		break;
 	}
 
 	return ret;
@@ -496,6 +531,9 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 	}
 
 	switch (imx6_pcie->drvdata->variant) {
+	case IMX8MQ:
+		reset_control_deassert(imx6_pcie->pciephy_reset);
+		break;
 	case IMX7D:
 		reset_control_deassert(imx6_pcie->pciephy_reset);
 		imx7d_pcie_wait_for_phy_pll_lock(imx6_pcie);
@@ -533,7 +571,36 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 
 static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
 {
+
+
+	unsigned int mask, val, offset;
+
+	mask = IMX6Q_GPR12_DEVICE_TYPE;
+	val  = FIELD_PREP(IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT);
+
 	switch (imx6_pcie->drvdata->variant) {
+	case IMX8MQ:
+		switch (imx6_pcie->controller_id) {
+		case 0:
+			offset = IOMUXC_GPR14;
+			break;
+		case 1:
+			offset = IOMUXC_GPR16;
+			mask = IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE;
+			val  = FIELD_PREP(IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE,
+					  PCI_EXP_TYPE_ROOT_PORT);
+			break;
+		default:
+			return;
+		}
+		/*
+		 * TODO: Currently this code assumes external
+		 * oscillator is being used
+		 */
+		regmap_update_bits(imx6_pcie->iomuxc_gpr, offset,
+				   IMX8MQ_GPR_PCIE_REF_USE_PAD,
+				   IMX8MQ_GPR_PCIE_REF_USE_PAD);
+		break;
 	case IMX7D:
 		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
 				   IMX7D_GPR12_PCIE_PHY_REFCLK_SEL, 0);
@@ -569,8 +636,7 @@ static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
 		break;
 	}
 
-	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
-			IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT << 12);
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, mask, val);
 }
 
 static int imx6_setup_phy_mpll(struct imx6_pcie *imx6_pcie)
@@ -667,6 +733,7 @@ static void imx6_pcie_ltssm_enable(struct device *dev)
 				   IMX6Q_GPR12_PCIE_CTL_2);
 		break;
 	case IMX7D:
+	case IMX8MQ:
 		reset_control_deassert(imx6_pcie->apps_reset);
 		break;
 	}
@@ -954,6 +1021,10 @@ static int imx6_pcie_probe(struct platform_device *pdev)
 	imx6_pcie->pci = pci;
 	imx6_pcie->drvdata = of_device_get_match_data(dev);
 
+	if (of_property_read_u32(node, "fsl,controller-id",
+				 &imx6_pcie->controller_id))
+		imx6_pcie->controller_id = 0;
+
 	dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	pci->dbi_base = devm_ioremap_resource(dev, dbi_base);
 	if (IS_ERR(pci->dbi_base))
@@ -1006,6 +1077,7 @@ static int imx6_pcie_probe(struct platform_device *pdev)
 		}
 		break;
 	case IMX7D:
+	case IMX8MQ:
 		imx6_pcie->pciephy_reset = devm_reset_control_get_exclusive(dev,
 									    "pciephy");
 		if (IS_ERR(imx6_pcie->pciephy_reset)) {
@@ -1110,6 +1182,9 @@ static const struct imx6_pcie_drvdata drvdata[] = {
 	[IMX7D] = {
 		.variant = IMX7D,
 	},
+	[IMX8MQ] = {
+		.variant = IMX8MQ,
+	},
 };
 
 static const struct of_device_id imx6_pcie_of_match[] = {
@@ -1117,6 +1192,7 @@ static const struct of_device_id imx6_pcie_of_match[] = {
 	{ .compatible = "fsl,imx6sx-pcie", .data = &drvdata[IMX6SX], },
 	{ .compatible = "fsl,imx6qp-pcie", .data = &drvdata[IMX6QP], },
 	{ .compatible = "fsl,imx7d-pcie",  .data = &drvdata[IMX7D],  },
+	{ .compatible = "fsl,imx8mq-pcie", .data = &drvdata[IMX8MQ], },
 	{},
 };
 
@@ -1133,6 +1209,7 @@ static struct platform_driver imx6_pcie_driver = {
 
 static int __init imx6_pcie_init(void)
 {
+#ifdef CONFIG_ARM
 	/*
 	 * Since probe() can be deferred we need to make sure that
 	 * hook_fault_code is not called after __init memory is freed
@@ -1142,6 +1219,7 @@ static int __init imx6_pcie_init(void)
 	 */
 	hook_fault_code(8, imx6q_pcie_abort_handler, SIGBUS, 0,
 			"external abort on non-linefetch");
+#endif
 
 	return platform_driver_register(&imx6_pcie_driver);
 }
-- 
2.19.1

Re: [PATCH v3 3/3] PCI: imx6: Add support for i.MX8MQ

[Leonard Crestez]

On Mon, 2018-12-17 at 20:07 -0800, Andrey Smirnov wrote:
> Add code needed to support i.MX8MQ variant.

>  static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
>  {
> +
> +
Remove empty lines?

> +	unsigned int mask, val, offset;
> +
> +	mask = IMX6Q_GPR12_DEVICE_TYPE;
> +	val  = FIELD_PREP(IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT);

... snip ...

> -	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
> -			IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT << 12);
> +	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, mask, val);

Maybe setting port type should be a separate function from init_phy?

Re: [PATCH v3 3/3] PCI: imx6: Add support for i.MX8MQ

[Rob Herring]

On Mon, Dec 17, 2018 at 08:07:02PM -0800, Andrey Smirnov wrote:
> Add code needed to support i.MX8MQ variant.
> 
> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Fabio Estevam <fabio.estevam@nxp.com>
> Cc: Chris Healy <cphealy@gmail.com>
> Cc: Lucas Stach <l.stach@pengutronix.de>
> Cc: Leonard Crestez <leonard.crestez@nxp.com>
> Cc: "A.s. Dong" <aisheng.dong@nxp.com>
> Cc: Richard Zhu <hongxing.zhu@nxp.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: devicetree@vger.kernel.org
> Cc: linux-imx@nxp.com
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-pci@vger.kernel.org
> ---
>  .../bindings/pci/fsl,imx6q-pcie.txt           |  6 +-
>  drivers/pci/controller/dwc/Kconfig            |  4 +-
>  drivers/pci/controller/dwc/pci-imx6.c         | 82 ++++++++++++++++++-
>  3 files changed, 87 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> index d514c1f2365f..1a10c313e8d7 100644
> --- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> +++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> @@ -9,6 +9,7 @@ Required properties:
>  	- "fsl,imx6sx-pcie",
>  	- "fsl,imx6qp-pcie"
>  	- "fsl,imx7d-pcie"
> +	- "fsl,imx8mq-pcie"
>  - reg: base address and length of the PCIe controller
>  - interrupts: A list of interrupt outputs of the controller. Must contain an
>    entry for each entry in the interrupt-names property.
> @@ -45,7 +46,7 @@ Additional required properties for imx6sx-pcie:
>    PCIE_PHY power domains
>  - power-domain-names: Must be "pcie", "pcie_phy"
>  
> -Additional required properties for imx7d-pcie:
> +Additional required properties for imx7d-pcie and imx8mq-pcie:
>  - power-domains: Must be set to a phandle pointing to PCIE_PHY power domain
>  - resets: Must contain phandles to PCIe-related reset lines exposed by SRC
>    IP block
> @@ -54,6 +55,9 @@ Additional required properties for imx7d-pcie:
>  	       - "apps"
>  	       - "turnoff"
>  
> +Additional required properties for imx8mq-pcie:
> +- fsl,controller-id: Logical ID of a given PCIE controller. PCIE1 is 0, PCIE2 is 1;
> +

Remove this.

If GPR register offset is what you need, then put that into DT. 
Typically, we'd have a property with iomuxc phandle and offset.

Rob

Re: [PATCH v3 3/3] PCI: imx6: Add support for i.MX8MQ

[Leonard Crestez]

On 12/18/2018 5:15 PM, Rob Herring wrote:
> On Mon, Dec 17, 2018 at 08:07:02PM -0800, Andrey Smirnov wrote:
>> Add code needed to support i.MX8MQ variant.
>>
>> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
>> Reviewed-by: Lucas Stach <l.stach@pengutronix.de>

>> --- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
>> +++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
>>   
>> +Additional required properties for imx8mq-pcie:
>> +- fsl,controller-id: Logical ID of a given PCIE controller. PCIE1 is 0, PCIE2 is 1;
>> +
> 
> Remove this.
> 
> If GPR register offset is what you need, then put that into DT.
> Typically, we'd have a property with iomuxc phandle and offset.

This series initially added explicit offsets but I suggested a single 
"controller-id" because:
  * There are multiple bit and byte offsets
  * Other imx8 SOCs also have 2x pcie with other bit/byte offsets

Hiding this behind a compatible string and single "controller-id" seem 
preferable to elaborating register maps in dt bindings. It also makes 
upgrades simpler: if features are added which use other bits there is no 
need to describe them in DT and deal with compatibility headaches.

Link to older thread: https://lkml.org/lkml/2018/11/29/888

It's possible my suggestion was misguided.

Re: [PATCH v3 3/3] PCI: imx6: Add support for i.MX8MQ

[Andrey Smirnov]

On Tue, Dec 18, 2018 at 1:34 AM Leonard Crestez <leonard.crestez@nxp.com> wrote:
>
> On Mon, 2018-12-17 at 20:07 -0800, Andrey Smirnov wrote:
> > Add code needed to support i.MX8MQ variant.
>
> >  static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
> >  {
> > +
> > +
> Remove empty lines?
>

Sure, will do.

> > +     unsigned int mask, val, offset;
> > +
> > +     mask = IMX6Q_GPR12_DEVICE_TYPE;
> > +     val  = FIELD_PREP(IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT);
>
> ... snip ...
>
> > -     regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
> > -                     IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT << 12);
> > +     regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, mask, val);
>
> Maybe setting port type should be a separate function from init_phy?

Sure, will change in v4.

Thanks,
Andrey Smirnov

Re: [PATCH v3 3/3] PCI: imx6: Add support for i.MX8MQ

[Rob Herring]

On Tue, Dec 18, 2018 at 12:09 PM Leonard Crestez
<leonard.crestez@nxp.com> wrote:
>
> On 12/18/2018 5:15 PM, Rob Herring wrote:
> > On Mon, Dec 17, 2018 at 08:07:02PM -0800, Andrey Smirnov wrote:
> >> Add code needed to support i.MX8MQ variant.
> >>
> >> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> >> Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
>
> >> --- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> >> +++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> >>
> >> +Additional required properties for imx8mq-pcie:
> >> +- fsl,controller-id: Logical ID of a given PCIE controller. PCIE1 is 0, PCIE2 is 1;
> >> +
> >
> > Remove this.
> >
> > If GPR register offset is what you need, then put that into DT.
> > Typically, we'd have a property with iomuxc phandle and offset.
>
> This series initially added explicit offsets but I suggested a single
> "controller-id" because:
>   * There are multiple bit and byte offsets
>   * Other imx8 SOCs also have 2x pcie with other bit/byte offsets
>
> Hiding this behind a compatible string and single "controller-id" seem
> preferable to elaborating register maps in dt bindings. It also makes
> upgrades simpler: if features are added which use other bits there is no
> need to describe them in DT and deal with compatibility headaches.

You already have an id for the controllers: the address. Use that if
you don't want to put the register offsets in DT.

Rob

Re: [PATCH v3 3/3] PCI: imx6: Add support for i.MX8MQ

[Andrey Smirnov]

On Tue, Dec 18, 2018 at 1:10 PM Rob Herring <robh@kernel.org> wrote:
>
> On Tue, Dec 18, 2018 at 12:09 PM Leonard Crestez
> <leonard.crestez@nxp.com> wrote:
> >
> > On 12/18/2018 5:15 PM, Rob Herring wrote:
> > > On Mon, Dec 17, 2018 at 08:07:02PM -0800, Andrey Smirnov wrote:
> > >> Add code needed to support i.MX8MQ variant.
> > >>
> > >> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> > >> Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
> >
> > >> --- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> > >> +++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> > >>
> > >> +Additional required properties for imx8mq-pcie:
> > >> +- fsl,controller-id: Logical ID of a given PCIE controller. PCIE1 is 0, PCIE2 is 1;
> > >> +
> > >
> > > Remove this.
> > >
> > > If GPR register offset is what you need, then put that into DT.
> > > Typically, we'd have a property with iomuxc phandle and offset.
> >
> > This series initially added explicit offsets but I suggested a single
> > "controller-id" because:
> >   * There are multiple bit and byte offsets
> >   * Other imx8 SOCs also have 2x pcie with other bit/byte offsets
> >
> > Hiding this behind a compatible string and single "controller-id" seem
> > preferable to elaborating register maps in dt bindings. It also makes
> > upgrades simpler: if features are added which use other bits there is no
> > need to describe them in DT and deal with compatibility headaches.
>
> You already have an id for the controllers: the address. Use that if
> you don't want to put the register offsets in DT.
>

Lucas, are you on board with this?

Thanks,
Andrey Smirnov

Re: [PATCH v3 3/3] PCI: imx6: Add support for i.MX8MQ

[Trent Piepho]

On Wed, 2018-12-19 at 16:47 -0800, Andrey Smirnov wrote:
> 
> > > This series initially added explicit offsets but I suggested a single
> > > "controller-id" because:
> > >   * There are multiple bit and byte offsets
> > >   * Other imx8 SOCs also have 2x pcie with other bit/byte offsets
> > > 
> > > Hiding this behind a compatible string and single "controller-id" seem
> > > preferable to elaborating register maps in dt bindings. It also makes
> > > upgrades simpler: if features are added which use other bits there is no
> > > need to describe them in DT and deal with compatibility headaches.
> > 
> > You already have an id for the controllers: the address. Use that if
> > you don't want to put the register offsets in DT.
> > 
> 
> Lucas, are you on board with this?

Does address here mean the address from the controller's reg property?
 
How do you map that address to the controller's index?  A giant table
of every soc so the soc type plus controller register address pair than
can be looked up in the driver?

I.e., on iMX8MQ the controller at 0x33800000 is controller 0 and so on
for every possible SoC address combination?

Not really a fan of that.

The situation here is that some registers for these controllers are
interleaved, right?  I.e., there's one register somewhere where bit 0
means enable controller 0 and bit 1 means enable controller 1 and so
on.

Isn't cell-index already the standard device tree property for this
kind of setup?

I know cell-index was historically also (ab)used in an attempt to
provide a fixed kernel device enumeration order, something now handled
better by chosen node aliases.

Re: [PATCH v3 3/3] PCI: imx6: Add support for i.MX8MQ

[Leonard Crestez]

On 12/20/2018 3:22 AM, Trent Piepho wrote:
> On Wed, 2018-12-19 at 16:47 -0800, Andrey Smirnov wrote:

>>>> This series initially added explicit offsets but I suggested a single
>>>> "controller-id" because:
>>>>    * There are multiple bit and byte offsets
>>>>    * Other imx8 SOCs also have 2x pcie with other bit/byte offsets
>>>>
>>>> Hiding this behind a compatible string and single "controller-id" seem
>>>> preferable to elaborating register maps in dt bindings. It also makes
>>>> upgrades simpler: if features are added which use other bits there is no
>>>> need to describe them in DT and deal with compatibility headaches.
>>>
>>> You already have an id for the controllers: the address. Use that if
>>> you don't want to put the register offsets in DT.
>>
>> Lucas, are you on board with this?
> 
> Does address here mean the address from the controller's reg property?
>   
> How do you map that address to the controller's index?

I guess you could have a constant for the address of the first 
controller and then substract. But hardcoding any sort of physical 
address feels wrong with DT.
> The situation here is that some registers for these controllers are
> interleaved, right?  I.e., there's one register somewhere where bit 0
> means enable controller 0 and bit 1 means enable controller 1 and so
> on.
> 
> Isn't cell-index already the standard device tree property for this
> kind of setup?

Look at how this cell-index property is documented in other bindings it 
seems to be an excellent fit: just rename controller-id to cell-index.

Re: [PATCH v3 3/3] PCI: imx6: Add support for i.MX8MQ

[Rob Herring]

On Wed, Dec 19, 2018 at 7:22 PM Trent Piepho <tpiepho@impinj.com> wrote:
>
> On Wed, 2018-12-19 at 16:47 -0800, Andrey Smirnov wrote:
> >
> > > > This series initially added explicit offsets but I suggested a single
> > > > "controller-id" because:
> > > >   * There are multiple bit and byte offsets
> > > >   * Other imx8 SOCs also have 2x pcie with other bit/byte offsets
> > > >
> > > > Hiding this behind a compatible string and single "controller-id" seem
> > > > preferable to elaborating register maps in dt bindings. It also makes
> > > > upgrades simpler: if features are added which use other bits there is no
> > > > need to describe them in DT and deal with compatibility headaches.
> > >
> > > You already have an id for the controllers: the address. Use that if
> > > you don't want to put the register offsets in DT.
> > >
> >
> > Lucas, are you on board with this?
>
> Does address here mean the address from the controller's reg property?

Yes.

> How do you map that address to the controller's index?  A giant table
> of every soc so the soc type plus controller register address pair than
> can be looked up in the driver?

You only need the 2-Nth instance addresses. A non-matching address can
be instance 0.

> I.e., on iMX8MQ the controller at 0x33800000 is controller 0 and so on
> for every possible SoC address combination?
>
> Not really a fan of that.

Well, this was not my first suggestion.

> The situation here is that some registers for these controllers are
> interleaved, right?  I.e., there's one register somewhere where bit 0
> means enable controller 0 and bit 1 means enable controller 1 and so
> on.

So? The only difference here is an additional mapping step.

> Isn't cell-index already the standard device tree property for this
> kind of setup?
>
> I know cell-index was historically also (ab)used in an attempt to
> provide a fixed kernel device enumeration order, something now handled
> better by chosen node aliases.

Don't use cell-index. Consider it a deprecated relic from OF that is
not used on FDT (though there probably are some cases it did get
used).

Rob

Re: [PATCH v3 3/3] PCI: imx6: Add support for i.MX8MQ

[Rob Herring]

On Tue, Dec 18, 2018 at 12:09 PM Leonard Crestez
<leonard.crestez@nxp.com> wrote:
>
> On 12/18/2018 5:15 PM, Rob Herring wrote:
> > On Mon, Dec 17, 2018 at 08:07:02PM -0800, Andrey Smirnov wrote:
> >> Add code needed to support i.MX8MQ variant.
> >>
> >> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> >> Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
>
> >> --- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> >> +++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> >>
> >> +Additional required properties for imx8mq-pcie:
> >> +- fsl,controller-id: Logical ID of a given PCIE controller. PCIE1 is 0, PCIE2 is 1;
> >> +
> >
> > Remove this.
> >
> > If GPR register offset is what you need, then put that into DT.
> > Typically, we'd have a property with iomuxc phandle and offset.
>
> This series initially added explicit offsets but I suggested a single
> "controller-id" because:
>   * There are multiple bit and byte offsets
>   * Other imx8 SOCs also have 2x pcie with other bit/byte offsets
>
> Hiding this behind a compatible string and single "controller-id" seem
> preferable to elaborating register maps in dt bindings. It also makes
> upgrades simpler: if features are added which use other bits there is no
> need to describe them in DT and deal with compatibility headaches.

You don't have to describe all bit and byte offsets. Once you know 1,
you can derive all the others. In fact, it doesn't have to be a
register field at all, just provide whatever identifier you need:

<$syscon 0>

and

<&syscon 1>

Rob