Date:   Fri, 6 Apr 2018 12:46:56 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Gustavo Pimentel <gustavo.pimentel@...opsys.com>,
        "bhelgaas@...gle.com" <bhelgaas@...gle.com>,
        "lorenzo.pieralisi@....com" <lorenzo.pieralisi@....com>,
        "Joao.Pinto@...opsys.com" <Joao.Pinto@...opsys.com>,
        "jingoohan1@...il.com" <jingoohan1@...il.com>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "mark.rutland@....com" <mark.rutland@....com>
CC:     "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH 2/8] PCI: dwc: designware: Add support for endpoint mode

Hi,

On Wednesday 04 April 2018 03:50 PM, Gustavo Pimentel wrote:
> On 02/04/2018 06:34, Kishon Vijay Abraham I wrote:
>> Hi,
>>
>> On Wednesday 28 March 2018 05:08 PM, Gustavo Pimentel wrote:
>>> The PCIe controller dual mode is capable of operating in host mode as well
>>> as endpoint mode by configuration, therefore this patch aims to add
>>> endpoint mode support to the designware driver.
>>>
>>> Signed-off-by: Gustavo Pimentel <gustavo.pimentel@...opsys.com>
>>> ---
>>>  drivers/pci/dwc/Kconfig                       |  45 ++++++--
>>>  drivers/pci/dwc/pcie-designware-plat.c        | 157 ++++++++++++++++++++++++--
>>>  drivers/pci/endpoint/functions/pci-epf-test.c |   5 +
>>>  3 files changed, 187 insertions(+), 20 deletions(-)
>>>
>>> diff --git a/drivers/pci/dwc/Kconfig b/drivers/pci/dwc/Kconfig
>>> index 2f3f5c5..3fd7daf 100644
>>> --- a/drivers/pci/dwc/Kconfig
>>> +++ b/drivers/pci/dwc/Kconfig
>>> @@ -7,8 +7,7 @@ config PCIE_DW
>>>  
>>>  config PCIE_DW_HOST
>>>          bool
>>> -	depends on PCI
>>> -	depends on PCI_MSI_IRQ_DOMAIN
>>> +	depends on PCI && PCI_MSI_IRQ_DOMAIN
>>>          select PCIE_DW
>>>  
>>>  config PCIE_DW_EP
>>> @@ -52,16 +51,42 @@ config PCI_DRA7XX_EP
>>>  
>>>  config PCIE_DW_PLAT
>>>  	bool "Platform bus based DesignWare PCIe Controller"
>>> -	depends on PCI
>>> -	depends on PCI_MSI_IRQ_DOMAIN
>>> -	select PCIE_DW_HOST
>>> -	---help---
>>> -	 This selects the DesignWare PCIe controller support. Select this if
>>> -	 you have a PCIe controller on Platform bus.
>>> +	help
>>> +	  There are two instances of PCIe controller in Designware IP.
>>> +	  This controller can work either as EP or RC. In order to enable
>>> +	  host-specific features PCIE_DW_PLAT_HOST must be selected and in
>>> +	  order to enable device-specific features PCIE_DW_PLAT_EP must be
>>> +	  selected.
>>>  
>>> -	 If you have a controller with this interface, say Y or M here.
>>> +config PCIE_DW_PLAT_HOST
>>> +	bool "Platform bus based DesignWare PCIe Controller - Host mode"
>>> +	depends on PCI && PCI_MSI_IRQ_DOMAIN
>>> +	select PCIE_DW_HOST
>>> +	select PCIE_DW_PLAT
>>> +	default y
>>> +	help
>>> +	  Enables support for the PCIe controller in the Designware IP to
>>> +	  work in host mode. There are two instances of PCIe controller in
>>> +	  Designware IP.
>>> +	  This controller can work either as EP or RC. In order to enable
>>> +	  host-specific features PCIE_DW_PLAT_HOST must be selected and in
>>> +	  order to enable device-specific features PCI_DW_PLAT_EP must be
>>> +	  selected.
>>>  
>>> -	 If unsure, say N.
>>> +config PCIE_DW_PLAT_EP
>>> +	bool "Platform bus based DesignWare PCIe Controller - Endpoint mode"
>>> +	depends on PCI && PCI_MSI_IRQ_DOMAIN
>>> +	depends on PCI_ENDPOINT
>>> +	select PCIE_DW_EP
>>> +	select PCIE_DW_PLAT
>>> +	help
>>> +	  Enables support for the PCIe controller in the Designware IP to
>>> +	  work in endpoint mode. There are two instances of PCIe controller
>>> +	  in Designware IP.
>>> +	  This controller can work either as EP or RC. In order to enable
>>> +	  host-specific features PCIE_DW_PLAT_HOST must be selected and in
>>> +	  order to enable device-specific features PCI_DW_PLAT_EP must be
>>> +	  selected.
>>>  
>>>  config PCI_EXYNOS
>>>  	bool "Samsung Exynos PCIe controller"
>>> diff --git a/drivers/pci/dwc/pcie-designware-plat.c b/drivers/pci/dwc/pcie-designware-plat.c
>>> index 5416aa8..921ab07 100644
>>> --- a/drivers/pci/dwc/pcie-designware-plat.c
>>> +++ b/drivers/pci/dwc/pcie-designware-plat.c
>>> @@ -12,19 +12,29 @@
>>>  #include <linux/interrupt.h>
>>>  #include <linux/kernel.h>
>>>  #include <linux/init.h>
>>> +#include <linux/of_device.h>
>>>  #include <linux/of_gpio.h>
>>>  #include <linux/pci.h>
>>>  #include <linux/platform_device.h>
>>>  #include <linux/resource.h>
>>>  #include <linux/signal.h>
>>>  #include <linux/types.h>
>>> +#include <linux/regmap.h>
>>>  
>>>  #include "pcie-designware.h"
>>>  
>>>  struct dw_plat_pcie {
>>> -	struct dw_pcie		*pci;
>>> +	struct dw_pcie			*pci;
>>> +	struct regmap			*regmap;
>>> +	enum dw_pcie_device_mode	mode;
>>>  };
>>>  
>>> +struct dw_plat_pcie_of_data {
>>> +	enum dw_pcie_device_mode	mode;
>>> +};
>>> +
>>> +static const struct of_device_id dw_plat_pcie_of_match[];
>>> +
>>>  static int dw_plat_pcie_host_init(struct pcie_port *pp)
>>>  {
>>>  	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>>> @@ -42,9 +52,61 @@ static const struct dw_pcie_host_ops dw_plat_pcie_host_ops = {
>>>  	.host_init = dw_plat_pcie_host_init,
>>>  };
>>>  
>>> -static int dw_plat_add_pcie_port(struct pcie_port *pp,
>>> +static int dw_plat_pcie_establish_link(struct dw_pcie *pci)
>>> +{
>>> +	dw_pcie_ep_linkup(&pci->ep);
>>
>> .start_link ops is used incorrectly here. .start_link is used when all the
>> endpoint side configuration is done and "is ready" to establish a link with the
>> host. But dw_pcie_ep_linkup is used to inform the function devices that the
>> link "has been" established.
> 
> If I move the dw_pcie_ep_linkup call from the dw_plat_pcie_establish_link to the
> dw_plat_pcie_ep_init function it would be more correct in your perspective? If
> not, where you suggest?

No, dw_pcie_ep_linkup is an optional function. If your platform gives a
notification when the link to the host is established, then you have to invoke
this function.

If you keep "linkup_notifier = false" in pci-epf-test.c, dw_pcie_ep_linkup
should be required.
> 
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static void dw_plat_pcie_stop_link(struct dw_pcie *pci)
>>> +{
>>> +
>>> +}
>>
>> Not necessary to have empty function here. pci-epc-core will not try to invoke
>> ops which are not populated.
> 
> Ok, I'll remove it.
> 
>>> +
>>> +static const struct dw_pcie_ops dw_pcie_ops = {
>>> +	.start_link = dw_plat_pcie_establish_link,
>>> +	.stop_link = dw_plat_pcie_stop_link,
>>> +};
>>> +
>>> +static void dw_plat_pcie_ep_init(struct dw_pcie_ep *ep)
>>> +{
>>> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>>> +	enum pci_barno bar;
>>> +
>>> +	for (bar = BAR_0; bar <= BAR_5; bar++)
>>> +		dw_pcie_ep_reset_bar(pci, bar);
>>> +}
>>> +
>>> +static int dw_plat_pcie_ep_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
>>> +				     enum pci_epc_irq_type type,
>>> +				     u8 interrupt_num)
>>> +{
>>> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>>> +
>>> +	switch (type) {
>>> +	case PCI_EPC_IRQ_LEGACY:
>>> +		dev_err(pci->dev, "EP cannot trigger legacy IRQs\n");
>>> +		return -EINVAL;
>>> +	case PCI_EPC_IRQ_MSI:
>>> +		return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
>>> +	default:
>>> +		dev_err(pci->dev, "UNKNOWN IRQ type\n");
>>> +	}
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static struct dw_pcie_ep_ops pcie_ep_ops = {
>>> +	.ep_init = dw_plat_pcie_ep_init,
>>> +	.raise_irq = dw_plat_pcie_ep_raise_irq,
>>> +};
>>> +
>>> +static int dw_plat_add_pcie_port(struct dw_plat_pcie *dw_plat_pcie,
>>>  				 struct platform_device *pdev)
>>>  {
>>> +	struct dw_pcie *pci = dw_plat_pcie->pci;
>>> +	struct pcie_port *pp = &pci->pp;
>>>  	struct device *dev = &pdev->dev;
>>>  	int ret;
>>>  
>>> @@ -63,15 +125,44 @@ static int dw_plat_add_pcie_port(struct pcie_port *pp,
>>>  
>>>  	ret = dw_pcie_host_init(pp);
>>>  	if (ret) {
>>> -		dev_err(dev, "failed to initialize host\n");
>>> +		dev_err(dev, "Failed to initialize host\n");
>>>  		return ret;
>>>  	}
>>>  
>>>  	return 0;
>>>  }
>>>  
>>> -static const struct dw_pcie_ops dw_pcie_ops = {
>>> -};
>>> +static int dw_plat_add_pcie_ep(struct dw_plat_pcie *dw_plat_pcie,
>>> +			       struct platform_device *pdev)
>>> +{
>>> +	int ret;
>>> +	struct dw_pcie_ep *ep;
>>> +	struct resource *res;
>>> +	struct device *dev = &pdev->dev;
>>> +	struct dw_pcie *pci = dw_plat_pcie->pci;
>>> +
>>> +	ep = &pci->ep;
>>> +	ep->ops = &pcie_ep_ops;
>>> +
>>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi2");
>>> +	pci->dbi_base2 = devm_ioremap(dev, res->start, resource_size(res));
>>> +	if (IS_ERR(pci->dbi_base2))
>>> +		return PTR_ERR(pci->dbi_base2);
>>> +
>>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "addr_space");
>>> +	if (!res)
>>> +		return -EINVAL;
>>> +
>>> +	ep->phys_base = res->start;
>>> +	ep->addr_size = resource_size(res);
>>> +
>>> +	ret = dw_pcie_ep_init(ep);
>>> +	if (ret) {
>>> +		dev_err(dev, "Failed to initialize endpoint\n");
>>> +		return ret;
>>> +	}
>>> +	return 0;
>>> +}
>>>  
>>>  static int dw_plat_pcie_probe(struct platform_device *pdev)
>>>  {
>>> @@ -80,6 +171,16 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
>>>  	struct dw_pcie *pci;
>>>  	struct resource *res;  /* Resource from DT */
>>>  	int ret;
>>> +	const struct of_device_id *match;
>>> +	const struct dw_plat_pcie_of_data *data;
>>> +	enum dw_pcie_device_mode mode;
>>> +
>>> +	match = of_match_device(dw_plat_pcie_of_match, dev);
>>> +	if (!match)
>>> +		return -EINVAL;
>>> +
>>> +	data = (struct dw_plat_pcie_of_data *)match->data;
>>> +	mode = (enum dw_pcie_device_mode)data->mode;
>>>  
>>>  	dw_plat_pcie = devm_kzalloc(dev, sizeof(*dw_plat_pcie), GFP_KERNEL);
>>>  	if (!dw_plat_pcie)
>>> @@ -93,23 +194,59 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
>>>  	pci->ops = &dw_pcie_ops;
>>>  
>>>  	dw_plat_pcie->pci = pci;
>>> +	dw_plat_pcie->mode = mode;
>>> +
>>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
>>> +	if (!res)
>>> +		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>>  
>>> -	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>>  	pci->dbi_base = devm_ioremap_resource(dev, res);
>>>  	if (IS_ERR(pci->dbi_base))
>>>  		return PTR_ERR(pci->dbi_base);
>>>  
>>>  	platform_set_drvdata(pdev, dw_plat_pcie);
>>>  
>>> -	ret = dw_plat_add_pcie_port(&pci->pp, pdev);
>>> -	if (ret < 0)
>>> -		return ret;
>>> +	switch (dw_plat_pcie->mode) {
>>> +	case DW_PCIE_RC_TYPE:
>>> +		if (!IS_ENABLED(CONFIG_PCIE_DW_PLAT_HOST))
>>> +			return -ENODEV;
>>> +
>>> +		ret = dw_plat_add_pcie_port(dw_plat_pcie, pdev);
>>> +		if (ret < 0)
>>> +			return ret;
>>> +		break;
>>> +	case DW_PCIE_EP_TYPE:
>>> +		if (!IS_ENABLED(CONFIG_PCIE_DW_PLAT_EP))
>>> +			return -ENODEV;
>>> +
>>> +		ret = dw_plat_add_pcie_ep(dw_plat_pcie, pdev);
>>> +		if (ret < 0)
>>> +			return ret;
>>> +		break;
>>> +	default:
>>> +		dev_err(dev, "INVALID device type %d\n", dw_plat_pcie->mode);
>>> +	}
>>>  
>>>  	return 0;
>>>  }
>>>  
>>> +static const struct dw_plat_pcie_of_data dw_plat_pcie_rc_of_data = {
>>> +	.mode = DW_PCIE_RC_TYPE,
>>> +};
>>> +
>>> +static const struct dw_plat_pcie_of_data dw_plat_pcie_ep_of_data = {
>>> +	.mode = DW_PCIE_EP_TYPE,
>>> +};
>>> +
>>>  static const struct of_device_id dw_plat_pcie_of_match[] = {
>>> -	{ .compatible = "snps,dw-pcie", },
>>> +	{
>>> +		.compatible = "snps,dw-pcie",
>>> +		.data = &dw_plat_pcie_rc_of_data,
>>> +	},
>>> +	{
>>> +		.compatible = "snps,dw-pcie-ep",
>>> +		.data = &dw_plat_pcie_ep_of_data,
>>> +	},
>>>  	{},
>>>  };
>>>  
>>> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
>>> index 64d8a17..d7de684 100644
>>> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
>>> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
>>> @@ -451,9 +451,14 @@ static int pci_epf_test_bind(struct pci_epf *epf)
>>>  	return 0;
>>>  }
>>>  
>>> +static const struct pci_epf_test_data pci_epf_data = {
>>> +	.linkup_notifier = false
>>> +};
>>> +
>>>  static const struct pci_epf_device_id pci_epf_test_ids[] = {
>>>  	{
>>>  		.name = "pci_epf_test",
>>> +		.driver_data = (kernel_ulong_t)&pci_epf_data,
>>
>> This will disable linkup_notifier for existing devices. Please add a new entry
>> to the table to make any modifications to driver data. (I have a configfs fix
>> for this to work. Will post that today).
> 
> Are you refering to this patch? https://patchwork.kernel.org/patch/10319695/
> Let's see if I understood it right, this patch will expose the some configfs
> (something like /sys/kernel/config/pci_ep/functions/pci_epf_test/func1/...) that
> ables me to disable the linkup notifier for existing devices without the need to
> change the code like I did, right?

Actually that patch doesn't add any configfs attribute entry. It just creates a
new configfs directory for every entry populated in pci_epf_device_id.

For example, If you have something like this

static const struct pci_epf_test_data k2g_data = {
	.test_reg_bar = BAR_1,
	.linkup_notifier = false
};

static const struct pci_epf_device_id pci_epf_test_ids[] = {
	{
		.name = "pci_epf_test",
	},
	{
		.name = "pci_epf_test_k2g",
		.driver_data = (kernel_ulong_t)&k2g_data,
	},
	{},
};

after [1], there should be 2 entries in /sys/kernel/config/pci_ep/functions/
pci_epf_test and pci_epf_test_k2g.

Here if you use pci_epf_test_k2g entry then the driver data associated with
pci_epf_test_k2g will be used.

Thanks
Kishon

[1] -> https://patchwork.kernel.org/patch/10319695/
> 
>>
>> Thanks
>> Kishon
>>
> 
> 

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