Re: [PATCH v10 07/10] PCI: sky1: Add PCIe host support for CIX Sky1

[Hans Zhang <hans.zhang@cixtech.com>]

On 10/31/2025 5:15 PM, Manivannan Sadhasivam wrote:
> EXTERNAL EMAIL
> 
> On Mon, Oct 20, 2025 at 12:28:54PM +0800, hans.zhang@cixtech.com wrote:
>> From: Hans Zhang <hans.zhang@cixtech.com>
>>
>> Add driver for the CIX Sky1 SoC PCIe Gen4 16 GT/s controller based
>> on the Cadence PCIe core.
>>
>> Supports MSI/MSI-x via GICv3, Single Virtual Channel, Single Function.
>>
>> Signed-off-by: Hans Zhang <hans.zhang@cixtech.com>
>> ---
>>   drivers/pci/controller/cadence/Kconfig    |  15 ++
>>   drivers/pci/controller/cadence/Makefile   |   1 +
>>   drivers/pci/controller/cadence/pci-sky1.c | 233 ++++++++++++++++++++++
>>   3 files changed, 249 insertions(+)
>>   create mode 100644 drivers/pci/controller/cadence/pci-sky1.c
>>
>> diff --git a/drivers/pci/controller/cadence/Kconfig b/drivers/pci/controller/cadence/Kconfig
>> index 0b96499ae354..ceff65934e5f 100644
>> --- a/drivers/pci/controller/cadence/Kconfig
>> +++ b/drivers/pci/controller/cadence/Kconfig
>> @@ -51,6 +51,21 @@ config PCIE_SG2042_HOST
>>          controller in host mode. Sophgo SG2042 PCIe controller uses Cadence
>>          PCIe core.
>>
>> +config PCI_SKY1_HOST
>> +     tristate "CIX SKY1 PCIe controller (host mode)"
>> +     depends on OF
>> +     select PCIE_CADENCE_HOST
>> +     select PCI_ECAM
>> +     help
>> +       Say Y here if you want to support the CIX SKY1 PCIe platform
>> +       controller in host mode. CIX SKY1 PCIe controller uses Cadence
>> +       HPA (High Performance Architecture IP [Second generation of
>> +       Cadence PCIe IP])
>> +
>> +       This driver requires Cadence PCIe core infrastructure
>> +       (PCIE_CADENCE_HOST) and hardware platform adaptation layer
>> +       to function.
>> +
>>   config PCI_J721E
>>        tristate
>>        select PCIE_CADENCE_HOST if PCI_J721E_HOST != n
>> diff --git a/drivers/pci/controller/cadence/Makefile b/drivers/pci/controller/cadence/Makefile
>> index 30189045a166..b8ec1cecfaa8 100644
>> --- a/drivers/pci/controller/cadence/Makefile
>> +++ b/drivers/pci/controller/cadence/Makefile
>> @@ -9,3 +9,4 @@ obj-$(CONFIG_PCIE_CADENCE_EP) += pcie-cadence-ep-mod.o
>>   obj-$(CONFIG_PCIE_CADENCE_PLAT) += pcie-cadence-plat.o
>>   obj-$(CONFIG_PCI_J721E) += pci-j721e.o
>>   obj-$(CONFIG_PCIE_SG2042_HOST) += pcie-sg2042.o
>> +obj-$(CONFIG_PCI_SKY1_HOST) += pci-sky1.o
>> diff --git a/drivers/pci/controller/cadence/pci-sky1.c b/drivers/pci/controller/cadence/pci-sky1.c
>> new file mode 100644
>> index 000000000000..4b0388394db3
>> --- /dev/null
>> +++ b/drivers/pci/controller/cadence/pci-sky1.c
>> @@ -0,0 +1,233 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * PCIe controller driver for CIX's sky1 SoCs
>> + *
>> + * Copyright 2025 Cix Technology Group Co., Ltd.
>> + * Author: Hans Zhang <hans.zhang@cixtech.com>
>> + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/of_device.h>
>> +#include <linux/pci.h>
>> +#include <linux/pci-ecam.h>
>> +#include <linux/pci_ids.h>
>> +
>> +#include "pcie-cadence.h"
>> +#include "pcie-cadence-host-common.h"
>> +
>> +#define STRAP_REG(n)                 ((n) * 0x04)
>> +#define STATUS_REG(n)                        ((n) * 0x04)
>> +#define LINK_TRAINING_ENABLE         BIT(0)
>> +#define LINK_COMPLETE                        BIT(0)
>> +
>> +#define SKY1_IP_REG_BANK             0x1000
>> +#define SKY1_IP_CFG_CTRL_REG_BANK    0x4c00
>> +#define SKY1_IP_AXI_MASTER_COMMON    0xf000
>> +#define SKY1_AXI_SLAVE                       0x9000
>> +#define SKY1_AXI_MASTER                      0xb000
>> +#define SKY1_AXI_HLS_REGISTERS               0xc000
>> +#define SKY1_AXI_RAS_REGISTERS               0xe000
>> +#define SKY1_DTI_REGISTERS           0xd000
>> +
>> +#define IP_REG_I_DBG_STS_0           0x420
>> +
>> +struct sky1_pcie {
>> +     struct cdns_pcie *cdns_pcie;
>> +     struct cdns_pcie_rc *cdns_pcie_rc;
>> +
>> +     struct resource *cfg_res;
>> +     struct resource *msg_res;
>> +     struct pci_config_window *cfg;
>> +     void __iomem *strap_base;
>> +     void __iomem *status_base;
>> +     void __iomem *reg_base;
>> +     void __iomem *cfg_base;
>> +     void __iomem *msg_base;
>> +};
>> +
>> +static int sky1_pcie_resource_get(struct platform_device *pdev,
>> +                               struct sky1_pcie *pcie)
>> +{
>> +     struct device *dev = &pdev->dev;
>> +     struct resource *res;
>> +     void __iomem *base;
>> +
>> +     base = devm_platform_ioremap_resource_byname(pdev, "reg");
>> +     if (IS_ERR(base))
>> +             return dev_err_probe(dev, PTR_ERR(base),
>> +                                  "unable to find \"reg\" registers\n");
>> +     pcie->reg_base = base;
>> +
>> +     res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cfg");
>> +     if (!res)
>> +             return dev_err_probe(dev, ENXIO, "unable to get \"cfg\" resource\n");
> 
> s/ENXIO/ENODEV


Hi Mani,

Thank you very much for your reply.

Will change.

> 
>> +     pcie->cfg_res = res;
>> +
>> +     base = devm_platform_ioremap_resource_byname(pdev, "rcsu_strap");
>> +     if (IS_ERR(base))
>> +             return dev_err_probe(dev, PTR_ERR(base),
>> +                                  "unable to find \"rcsu_strap\" registers\n");
>> +     pcie->strap_base = base;
>> +
>> +     base = devm_platform_ioremap_resource_byname(pdev, "rcsu_status");
>> +     if (IS_ERR(base))
>> +             return dev_err_probe(dev, PTR_ERR(base),
>> +                                  "unable to find \"rcsu_status\" registers\n");
>> +     pcie->status_base = base;
>> +
>> +     res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "msg");
>> +     if (!res)
>> +             return dev_err_probe(dev, ENXIO, "unable to get \"msg\" resource\n");
> 
> s/ENXIO/ENODEV

Will change.

> 
>> +     pcie->msg_res = res;
>> +     pcie->msg_base = devm_ioremap_resource(dev, res);
>> +     if (IS_ERR(pcie->msg_base)) {
>> +             return dev_err_probe(dev, PTR_ERR(pcie->msg_base),
>> +                                  "unable to ioremap msg resource\n");
>> +     }
>> +
>> +     return 0;
>> +}
>> +
>> +static int sky1_pcie_start_link(struct cdns_pcie *cdns_pcie)
>> +{
>> +     struct sky1_pcie *pcie = dev_get_drvdata(cdns_pcie->dev);
>> +     u32 val;
>> +
>> +     val = readl(pcie->strap_base + STRAP_REG(1));
>> +     val |= LINK_TRAINING_ENABLE;
>> +     writel(val, pcie->strap_base + STRAP_REG(1));
>> +
>> +     return 0;
>> +}
>> +
>> +static void sky1_pcie_stop_link(struct cdns_pcie *cdns_pcie)
>> +{
>> +     struct sky1_pcie *pcie = dev_get_drvdata(cdns_pcie->dev);
>> +     u32 val;
>> +
>> +     val = readl(pcie->strap_base + STRAP_REG(1));
>> +     val &= ~LINK_TRAINING_ENABLE;
>> +     writel(val, pcie->strap_base + STRAP_REG(1));
>> +}
>> +
>> +static bool sky1_pcie_link_up(struct cdns_pcie *cdns_pcie)
>> +{
>> +     u32 val;
>> +
>> +     val = cdns_pcie_hpa_readl(cdns_pcie, REG_BANK_IP_REG,
>> +                               IP_REG_I_DBG_STS_0);
>> +     return val & LINK_COMPLETE;
>> +}
>> +
>> +static const struct cdns_pcie_ops sky1_pcie_ops = {
>> +     .start_link = sky1_pcie_start_link,
>> +     .stop_link = sky1_pcie_stop_link,
>> +     .link_up = sky1_pcie_link_up,
>> +};
>> +
>> +static int sky1_pcie_probe(struct platform_device *pdev)
>> +{
>> +     struct cdns_plat_pcie_of_data *reg_off;
>> +     struct device *dev = &pdev->dev;
>> +     struct pci_host_bridge *bridge;
>> +     struct cdns_pcie *cdns_pcie;
>> +     struct resource_entry *bus;
>> +     struct cdns_pcie_rc *rc;
>> +     struct sky1_pcie *pcie;
>> +     int ret;
>> +
>> +     pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
>> +     if (!pcie)
>> +             return -ENOMEM;
>> +
>> +     bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));
>> +     if (!bridge)
>> +             return -ENOMEM;
>> +
>> +     ret = sky1_pcie_resource_get(pdev, pcie);
>> +     if (ret < 0)
>> +             return ret;
>> +
>> +     bus = resource_list_first_type(&bridge->windows, IORESOURCE_BUS);
>> +     if (!bus)
>> +             return -ENODEV;
>> +
>> +     pcie->cfg = pci_ecam_create(dev, pcie->cfg_res, bus->res,
>> +                                 &pci_generic_ecam_ops);
>> +     if (IS_ERR(pcie->cfg))
>> +             return PTR_ERR(pcie->cfg);
>> +
>> +     bridge->ops = (struct pci_ops *)&pci_generic_ecam_ops.pci_ops;
>> +     rc = pci_host_bridge_priv(bridge);
>> +     rc->ecam_supported = 1;
>> +     rc->cfg_base = pcie->cfg->win;
>> +     rc->cfg_res = &pcie->cfg->res;
>> +
>> +     cdns_pcie = &rc->pcie;
>> +     cdns_pcie->dev = dev;
>> +     cdns_pcie->ops = &sky1_pcie_ops;
>> +     cdns_pcie->reg_base = pcie->reg_base;
>> +     cdns_pcie->msg_res = pcie->msg_res;
>> +     cdns_pcie->is_rc = 1;
>> +
>> +     reg_off = devm_kzalloc(dev, sizeof(*reg_off), GFP_KERNEL);
>> +     if (!reg_off)
>> +             return -ENOMEM;
>> +
>> +     reg_off->ip_reg_bank_offset = SKY1_IP_REG_BANK;
>> +     reg_off->ip_cfg_ctrl_reg_offset = SKY1_IP_CFG_CTRL_REG_BANK;
>> +     reg_off->axi_mstr_common_offset = SKY1_IP_AXI_MASTER_COMMON;
>> +     reg_off->axi_slave_offset = SKY1_AXI_SLAVE;
>> +     reg_off->axi_master_offset = SKY1_AXI_MASTER;
>> +     reg_off->axi_hls_offset = SKY1_AXI_HLS_REGISTERS;
>> +     reg_off->axi_ras_offset = SKY1_AXI_RAS_REGISTERS;
>> +     reg_off->axi_dti_offset = SKY1_DTI_REGISTERS;
>> +     cdns_pcie->cdns_pcie_reg_offsets = reg_off;
>> +
>> +     pcie->cdns_pcie = cdns_pcie;
>> +     pcie->cdns_pcie_rc = rc;
>> +     pcie->cfg_base = rc->cfg_base;
>> +     bridge->sysdata = pcie->cfg;
>> +
>> +     rc->vendor_id = PCI_VENDOR_ID_CIX;
>> +     rc->device_id = PCI_DEVICE_ID_CIX_SKY1;
>> +     rc->no_inbound_map = 1;
>> +
>> +     dev_set_drvdata(dev, pcie);
>> +
>> +     ret = cdns_pcie_hpa_host_setup(rc);
>> +     if (ret < 0) {
>> +             pci_ecam_free(pcie->cfg);
>> +             return ret;
>> +     }
>> +
>> +     return 0;
>> +}
>> +
>> +static const struct of_device_id of_sky1_pcie_match[] = {
>> +     { .compatible = "cix,sky1-pcie-host", },
>> +     {},
>> +};
> 
> Missing MODULE_DEVICE_TABLE(). Your driver is not going to be auto loaded.

Will add.

> 
>> +
>> +static void sky1_pcie_remove(struct platform_device *pdev)
>> +{
>> +     struct sky1_pcie *pcie = platform_get_drvdata(pdev);
>> +
>> +     pci_ecam_free(pcie->cfg);
>> +}
>> +
>> +static struct platform_driver sky1_pcie_driver = {
>> +     .probe  = sky1_pcie_probe,
>> +     .remove = sky1_pcie_remove,
>> +     .driver = {
>> +             .name = "sky1-pcie",
>> +             .of_match_table = of_sky1_pcie_match,
> 
> Use .probe_type = PROBE_PREFER_ASYNCHRONOUS.

Will change. Thank you for your reminder.

Best regards,
Hans

> 
> - Mani
> 
> --
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