PCI: dwc: Prepare the driver for enabling ECAM mechanism using iATU 'CFG Shift Feature'

In order to enable PCIe ECAM mechanism in DWC driver as per the 'CFG Shift
Feature' documented in Designware databook r5.20a, sec 3.10.10.3, prepare
the driver to handle the one time iATU setup and creating ECAM window.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
[mani: splitted the preparatory code into a separate commit for bisectability]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://patch.msgid.link/20250923-controller-dwc-ecam-v10-2-e84390ba75fa@kernel.org

diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
index deafc512b07928e30e93b814ad325a6be7dbcf75..dc0271203909fbcfa2b47733693d99b7a069426b 100644 (file)
--- a/drivers/pci/controller/dwc/Kconfig
+++ b/drivers/pci/controller/dwc/Kconfig
@@ -20,6 +20,7 @@ config PCIE_DW_HOST
        bool
        select PCIE_DW
        select IRQ_MSI_LIB
+       select PCI_HOST_COMMON
 
 config PCIE_DW_EP
        bool

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 952f8594b501254d2b2de5d5e056e16d2aa8d4b7..94e0fe11a0b062d0f14e09fe586e20bde46a4266 100644 (file)
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -413,6 +413,67 @@ static void dw_pcie_host_request_msg_tlp_res(struct dw_pcie_rp *pp)
        }
 }
 
+static int dw_pcie_config_ecam_iatu(struct dw_pcie_rp *pp)
+{
+       struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+       struct dw_pcie_ob_atu_cfg atu = {0};
+       resource_size_t bus_range_max;
+       struct resource_entry *bus;
+       int ret;
+
+       bus = resource_list_first_type(&pp->bridge->windows, IORESOURCE_BUS);
+
+       /*
+        * Root bus under the host bridge doesn't require any iATU configuration
+        * as DBI region will be used to access root bus config space.
+        * Immediate bus under Root Bus, needs type 0 iATU configuration and
+        * remaining buses need type 1 iATU configuration.
+        */
+       atu.index = 0;
+       atu.type = PCIE_ATU_TYPE_CFG0;
+       atu.parent_bus_addr = pp->cfg0_base + SZ_1M;
+       /* 1MiB is to cover 1 (bus) * 32 (devices) * 8 (functions) */
+       atu.size = SZ_1M;
+       atu.ctrl2 = PCIE_ATU_CFG_SHIFT_MODE_ENABLE;
+       ret = dw_pcie_prog_outbound_atu(pci, &atu);
+       if (ret)
+               return ret;
+
+       bus_range_max = resource_size(bus->res);
+
+       if (bus_range_max < 2)
+               return 0;
+
+       /* Configure remaining buses in type 1 iATU configuration */
+       atu.index = 1;
+       atu.type = PCIE_ATU_TYPE_CFG1;
+       atu.parent_bus_addr = pp->cfg0_base + SZ_2M;
+       atu.size = (SZ_1M * bus_range_max) - SZ_2M;
+       atu.ctrl2 = PCIE_ATU_CFG_SHIFT_MODE_ENABLE;
+
+       return dw_pcie_prog_outbound_atu(pci, &atu);
+}
+
+static int dw_pcie_create_ecam_window(struct dw_pcie_rp *pp, struct resource *res)
+{
+       struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+       struct device *dev = pci->dev;
+       struct resource_entry *bus;
+
+       bus = resource_list_first_type(&pp->bridge->windows, IORESOURCE_BUS);
+       if (!bus)
+               return -ENODEV;
+
+       pp->cfg = pci_ecam_create(dev, res, bus->res, &pci_generic_ecam_ops);
+       if (IS_ERR(pp->cfg))
+               return PTR_ERR(pp->cfg);
+
+       pci->dbi_base = pp->cfg->win;
+       pci->dbi_phys_addr = res->start;
+
+       return 0;
+}
+
 static int dw_pcie_host_get_resources(struct dw_pcie_rp *pp)
 {
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
@@ -422,10 +483,6 @@ static int dw_pcie_host_get_resources(struct dw_pcie_rp *pp)
        struct resource *res;
        int ret;
 
-       ret = dw_pcie_get_resources(pci);
-       if (ret)
-               return ret;
-
        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "config");
        if (!res) {
                dev_err(dev, "Missing \"config\" reg space\n");
@@ -435,9 +492,31 @@ static int dw_pcie_host_get_resources(struct dw_pcie_rp *pp)
        pp->cfg0_size = resource_size(res);
        pp->cfg0_base = res->start;
 
-       pp->va_cfg0_base = devm_pci_remap_cfg_resource(dev, res);
-       if (IS_ERR(pp->va_cfg0_base))
-               return PTR_ERR(pp->va_cfg0_base);
+       if (pp->ecam_enabled) {
+               ret = dw_pcie_create_ecam_window(pp, res);
+               if (ret)
+                       return ret;
+
+               pp->bridge->ops = (struct pci_ops *)&pci_generic_ecam_ops.pci_ops;
+               pp->bridge->sysdata = pp->cfg;
+               pp->cfg->priv = pp;
+       } else {
+               pp->va_cfg0_base = devm_pci_remap_cfg_resource(dev, res);
+               if (IS_ERR(pp->va_cfg0_base))
+                       return PTR_ERR(pp->va_cfg0_base);
+
+               /* Set default bus ops */
+               pp->bridge->ops = &dw_pcie_ops;
+               pp->bridge->child_ops = &dw_child_pcie_ops;
+               pp->bridge->sysdata = pp;
+       }
+
+       ret = dw_pcie_get_resources(pci);
+       if (ret) {
+               if (pp->cfg)
+                       pci_ecam_free(pp->cfg);
+               return ret;
+       }
 
        /* Get the I/O range from DT */
        win = resource_list_first_type(&pp->bridge->windows, IORESOURCE_IO);
@@ -476,14 +555,10 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
        if (ret)
                return ret;
 
-       /* Set default bus ops */
-       bridge->ops = &dw_pcie_ops;
-       bridge->child_ops = &dw_child_pcie_ops;
-
        if (pp->ops->init) {
                ret = pp->ops->init(pp);
                if (ret)
-                       return ret;
+                       goto err_free_ecam;
        }
 
        if (pci_msi_enabled()) {
@@ -525,6 +600,14 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
        if (ret)
                goto err_free_msi;
 
+       if (pp->ecam_enabled) {
+               ret = dw_pcie_config_ecam_iatu(pp);
+               if (ret) {
+                       dev_err(dev, "Failed to configure iATU in ECAM mode\n");
+                       goto err_free_msi;
+               }
+       }
+
        /*
         * Allocate the resource for MSG TLP before programming the iATU
         * outbound window in dw_pcie_setup_rc(). Since the allocation depends
@@ -560,8 +643,6 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
                /* Ignore errors, the link may come up later */
                dw_pcie_wait_for_link(pci);
 
-       bridge->sysdata = pp;
-
        ret = pci_host_probe(bridge);
        if (ret)
                goto err_stop_link;
@@ -587,6 +668,10 @@ err_deinit_host:
        if (pp->ops->deinit)
                pp->ops->deinit(pp);
 
+err_free_ecam:
+       if (pp->cfg)
+               pci_ecam_free(pp->cfg);
+
        return ret;
 }
 EXPORT_SYMBOL_GPL(dw_pcie_host_init);
@@ -609,6 +694,9 @@ void dw_pcie_host_deinit(struct dw_pcie_rp *pp)
 
        if (pp->ops->deinit)
                pp->ops->deinit(pp);
+
+       if (pp->cfg)
+               pci_ecam_free(pp->cfg);
 }
 EXPORT_SYMBOL_GPL(dw_pcie_host_deinit);
 

diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
index 93da8a26c9313dfdd6b269a90bbfb017aab2abe7..ee8caae1edbd44c10e6986430a6932c10f20a9eb 100644 (file)
--- a/drivers/pci/controller/dwc/pcie-designware.c
+++ b/drivers/pci/controller/dwc/pcie-designware.c
@@ -575,7 +575,7 @@ int dw_pcie_prog_outbound_atu(struct dw_pcie *pci,
                val = dw_pcie_enable_ecrc(val);
        dw_pcie_writel_atu_ob(pci, atu->index, PCIE_ATU_REGION_CTRL1, val);
 
-       val = PCIE_ATU_ENABLE;
+       val = PCIE_ATU_ENABLE | atu->ctrl2;
        if (atu->type == PCIE_ATU_TYPE_MSG) {
                /* The data-less messages only for now */
                val |= PCIE_ATU_INHIBIT_PAYLOAD | atu->code;

diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 9eb3c4c762ddca7d6faff3a98a54b37d7cd9f11b..779868e8fa8fd78e5f35cd0fa2575f52cc07c335 100644 (file)
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -20,6 +20,7 @@
 #include <linux/irq.h>
 #include <linux/msi.h>
 #include <linux/pci.h>
+#include <linux/pci-ecam.h>
 #include <linux/reset.h>
 
 #include <linux/pci-epc.h>
@@ -168,6 +169,7 @@
 #define PCIE_ATU_REGION_CTRL2          0x004
 #define PCIE_ATU_ENABLE                        BIT(31)
 #define PCIE_ATU_BAR_MODE_ENABLE       BIT(30)
+#define PCIE_ATU_CFG_SHIFT_MODE_ENABLE BIT(28)
 #define PCIE_ATU_INHIBIT_PAYLOAD       BIT(22)
 #define PCIE_ATU_FUNC_NUM_MATCH_EN      BIT(19)
 #define PCIE_ATU_LOWER_BASE            0x008
@@ -386,6 +388,7 @@ struct dw_pcie_ob_atu_cfg {
        u8 func_no;
        u8 code;
        u8 routing;
+       u32 ctrl2;
        u64 parent_bus_addr;
        u64 pci_addr;
        u64 size;
@@ -424,6 +427,8 @@ struct dw_pcie_rp {
        struct resource         *msg_res;
        bool                    use_linkup_irq;
        struct pci_eq_presets   presets;
+       struct pci_config_window *cfg;
+       bool                    ecam_enabled;
 };
 
 struct dw_pcie_ep_ops {