[PATCH v4 0/4] PCI: Keystone: Enable loadable module support

[PATCH v4 0/4] PCI: Keystone: Enable loadable module support

[Siddharth Vadapalli]

Hello,

This series enables support for the 'pci-keystone.c' driver to be built
as a loadable module. The motivation for the series is that PCIe is not
a necessity for booting Linux due to which the 'pci-keystone.c' driver
does not need to be built-in.

Series is based on 6.18-rc1 tag of Mainline Linux.

DEPENDENCY
----------
This series has __NO__ dependencies since the dependencies stated in the
cover-letter of the v3 series at:
https://lore.kernel.org/r/20250922071222.2814937-1-s-vadapalli@ti.com/
have been satisfied.

v3:
https://lore.kernel.org/r/20250922071222.2814937-1-s-vadapalli@ti.com/
Changes since v3:
- Rebased series on 6.18-rc1 tag of Mainline Linux.
- Patch 4 has been updated to remove the '__init' keyword from functions
  to avoid triggering an exception due to '__init' memory being freed
  before functions are invoked. This is the equivalent of:
  https://lore.kernel.org/r/20250912100802.3136121-3-s-vadapalli@ti.com/
  while addressing Bjorn's feedback at:
  https://lore.kernel.org/r/20251002143627.GA267439@bhelgaas/
  by introducing a new 'init' function specifically for registering the
  fault handler while the rest of the driver remains the same.

Series has been tested on AM654-EVM with an NVMe SSD connected to the
PCIe Connector of the EVM. Test Logs:
https://gist.github.com/Siddharth-Vadapalli-at-TI/332e8d65c66ed93e95c2d89ec1ee3f68

Regards,
Siddharth.

Siddharth Vadapalli (4):
  PCI: Export pci_get_host_bridge_device() for use by pci-keystone
  PCI: dwc: Export dw_pcie_allocate_domains() and
    dw_pcie_ep_raise_msix_irq()
  PCI: keystone: Exit ks_pcie_probe() for invalid mode
  PCI: keystone: Add support to build as a loadable module

 drivers/pci/controller/dwc/Kconfig            |  6 +--
 drivers/pci/controller/dwc/pci-keystone.c     | 38 +++++++++++++------
 .../pci/controller/dwc/pcie-designware-ep.c   |  1 +
 .../pci/controller/dwc/pcie-designware-host.c |  1 +
 drivers/pci/host-bridge.c                     |  1 +
 include/linux/pci.h                           |  1 +
 6 files changed, 33 insertions(+), 15 deletions(-)

-- 
2.51.0

[PATCH v4 1/4] PCI: Export pci_get_host_bridge_device() for use by pci-keystone

[Siddharth Vadapalli]

The pci-keystone.c driver uses the 'pci_get_host_bridge_device()' helper.
In preparation for enabling the pci-keystone.c driver to be built as a
loadable module, export 'pci_get_host_bridge_device()'.

Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
---

v3:
https://lore.kernel.org/r/20250922071222.2814937-2-s-vadapalli@ti.com/
Changes since v3:
- Rebased patch on 6.18-rc1 tag of Mainline Linux.

Regards,
Siddharth.

 drivers/pci/host-bridge.c | 1 +
 include/linux/pci.h       | 1 +
 2 files changed, 2 insertions(+)

diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
index afa50b446567..be5ef6516cff 100644
--- a/drivers/pci/host-bridge.c
+++ b/drivers/pci/host-bridge.c
@@ -33,6 +33,7 @@ struct device *pci_get_host_bridge_device(struct pci_dev *dev)
 	kobject_get(&bridge->kobj);
 	return bridge;
 }
+EXPORT_SYMBOL_GPL(pci_get_host_bridge_device);
 
 void  pci_put_host_bridge_device(struct device *dev)
 {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index d1fdf81fbe1e..b253cbc27d36 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -646,6 +646,7 @@ struct pci_host_bridge *pci_alloc_host_bridge(size_t priv);
 struct pci_host_bridge *devm_pci_alloc_host_bridge(struct device *dev,
 						   size_t priv);
 void pci_free_host_bridge(struct pci_host_bridge *bridge);
+struct device *pci_get_host_bridge_device(struct pci_dev *dev);
 struct pci_host_bridge *pci_find_host_bridge(struct pci_bus *bus);
 
 void pci_set_host_bridge_release(struct pci_host_bridge *bridge,
-- 
2.51.0

[PATCH v4 2/4] PCI: dwc: Export dw_pcie_allocate_domains() and dw_pcie_ep_raise_msix_irq()

[Siddharth Vadapalli]

The pci-keystone.c driver uses the functions 'dw_pcie_allocate_domains()'
and 'dw_pcie_ep_raise_msix_irq()'. In preparation for enabling the
pci-keystone.c driver to be built as a loadable module, export them.

Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
---

v3:
https://lore.kernel.org/r/20250922071222.2814937-3-s-vadapalli@ti.com/
Changes since v3:
- Rebased patch on 6.18-rc1 tag of Mainline Linux.

Regards,
Siddharth.

 drivers/pci/controller/dwc/pcie-designware-ep.c   | 1 +
 drivers/pci/controller/dwc/pcie-designware-host.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 7f2112c2fb21..19571ac2b961 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -797,6 +797,7 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(dw_pcie_ep_raise_msix_irq);
 
 /**
  * dw_pcie_ep_cleanup - Cleanup DWC EP resources after fundamental reset
diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 20c9333bcb1c..d74bc571f65d 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -232,6 +232,7 @@ int dw_pcie_allocate_domains(struct dw_pcie_rp *pp)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(dw_pcie_allocate_domains);
 
 void dw_pcie_free_msi(struct dw_pcie_rp *pp)
 {
-- 
2.51.0

[PATCH v4 3/4] PCI: keystone: Exit ks_pcie_probe() for invalid mode

[Siddharth Vadapalli]

Commit under Fixes introduced support for PCIe EP mode on AM654x platforms.
When the mode happens to be either "DW_PCIE_RC_TYPE" or "DW_PCIE_EP_TYPE",
the PCIe Controller is configured accordingly. However, when the mode is
neither of them, an error message is displayed but the driver probe
succeeds. Since this "invalid" mode is not associated with a functional
PCIe Controller, the probe should fail.

Fix the behavior by exiting "ks_pcie_probe()" with the return value of
"-EINVAL" in addition to displaying the existing error message when the
mode is invalid.

Fixes: 23284ad677a9 ("PCI: keystone: Add support for PCIe EP in AM654x Platforms")
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
---

NOTE: As stated in the v3 patch, although a Fixes tag has been added,
the patch doesn't have to be backported. Hence, 'stable' hasn't been
CCed on purpose.

v3:
https://lore.kernel.org/r/20250922071222.2814937-4-s-vadapalli@ti.com/
Changes since v3:
- Rebased patch on 6.18-rc1 tag of Mainline Linux.

Regards,
Siddharth.

 drivers/pci/controller/dwc/pci-keystone.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
index eb00aa380722..25b8193ffbcf 100644
--- a/drivers/pci/controller/dwc/pci-keystone.c
+++ b/drivers/pci/controller/dwc/pci-keystone.c
@@ -1337,6 +1337,8 @@ static int ks_pcie_probe(struct platform_device *pdev)
 		break;
 	default:
 		dev_err(dev, "INVALID device type %d\n", mode);
+		ret = -EINVAL;
+		goto err_get_sync;
 	}
 
 	ks_pcie_enable_error_irq(ks_pcie);
-- 
2.51.0

[PATCH v4 4/4] PCI: keystone: Add support to build as a loadable module

[Siddharth Vadapalli]

The 'pci-keystone.c' driver is the application/glue/wrapper driver for the
Designware PCIe Controllers on TI SoCs. Now that all of the helper APIs
that the 'pci-keystone.c' driver depends upon have been exported for use,
enable support to build the driver as a loadable module.

Additionally, the functions marked by the '__init' keyword may be invoked:
a) After a probe deferral
OR
b) During a delayed probe - Delay attributed to driver being built as a
   loadable module

In both of the cases mentioned above, the '__init' memory will be freed
before the functions are invoked. This results in an exception of the form:

	Unable to handle kernel paging request at virtual address ...
	Mem abort info:
	...
	pc : ks_pcie_host_init+0x0/0x540
	lr : dw_pcie_host_init+0x170/0x498
	...
	ks_pcie_host_init+0x0/0x540 (P)
	ks_pcie_probe+0x728/0x84c
	platform_probe+0x5c/0x98
	really_probe+0xbc/0x29c
	__driver_probe_device+0x78/0x12c
	driver_probe_device+0xd8/0x15c
	...

To address this, introduce a new function namely 'ks_pcie_init()' to
register the 'fault handler' while removing the '__init' keyword from
existing functions.

Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
---

v3:
https://lore.kernel.org/r/20250922071222.2814937-5-s-vadapalli@ti.com/
Changes since v3:
- Rebased patch on 6.18-rc1 tag of Mainline Linux.
- The '__init' keyword has been removed from functions to avoid triggering
  an exception due to '__init' memory being freed before functions are invoked.
  This is the equivalent of:
  https://lore.kernel.org/r/20250912100802.3136121-3-s-vadapalli@ti.com/
  while addressing Bjorn's feedback at:
  https://lore.kernel.org/r/20251002143627.GA267439@bhelgaas/
  by introducing 'ks_pcie_init()' function specifically for registering the
  fault handler while the rest of the driver remains the same.

Regards,
Siddharth.

 drivers/pci/controller/dwc/Kconfig        |  6 ++--
 drivers/pci/controller/dwc/pci-keystone.c | 36 +++++++++++++++--------
 2 files changed, 27 insertions(+), 15 deletions(-)

diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
index 349d4657393c..561a7266e21b 100644
--- a/drivers/pci/controller/dwc/Kconfig
+++ b/drivers/pci/controller/dwc/Kconfig
@@ -483,10 +483,10 @@ config PCI_DRA7XX_EP
 	  This uses the DesignWare core.
 
 config PCI_KEYSTONE
-	bool
+	tristate
 
 config PCI_KEYSTONE_HOST
-	bool "TI Keystone PCIe controller (host mode)"
+	tristate "TI Keystone PCIe controller (host mode)"
 	depends on ARCH_KEYSTONE || ARCH_K3 || COMPILE_TEST
 	depends on PCI_MSI
 	select PCIE_DW_HOST
@@ -498,7 +498,7 @@ config PCI_KEYSTONE_HOST
 	  DesignWare core functions to implement the driver.
 
 config PCI_KEYSTONE_EP
-	bool "TI Keystone PCIe controller (endpoint mode)"
+	tristate "TI Keystone PCIe controller (endpoint mode)"
 	depends on ARCH_KEYSTONE || ARCH_K3 || COMPILE_TEST
 	depends on PCI_ENDPOINT
 	select PCIE_DW_EP
diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
index 25b8193ffbcf..8e53822a903f 100644
--- a/drivers/pci/controller/dwc/pci-keystone.c
+++ b/drivers/pci/controller/dwc/pci-keystone.c
@@ -17,6 +17,7 @@
 #include <linux/irqchip/chained_irq.h>
 #include <linux/irqdomain.h>
 #include <linux/mfd/syscon.h>
+#include <linux/module.h>
 #include <linux/msi.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
@@ -799,7 +800,7 @@ static int ks_pcie_fault(unsigned long addr, unsigned int fsr,
 }
 #endif
 
-static int __init ks_pcie_init_id(struct keystone_pcie *ks_pcie)
+static int ks_pcie_init_id(struct keystone_pcie *ks_pcie)
 {
 	int ret;
 	unsigned int id;
@@ -831,7 +832,7 @@ static int __init ks_pcie_init_id(struct keystone_pcie *ks_pcie)
 	return 0;
 }
 
-static int __init ks_pcie_host_init(struct dw_pcie_rp *pp)
+static int ks_pcie_host_init(struct dw_pcie_rp *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
 	struct keystone_pcie *ks_pcie = to_keystone_pcie(pci);
@@ -861,15 +862,6 @@ static int __init ks_pcie_host_init(struct dw_pcie_rp *pp)
 	if (ret < 0)
 		return ret;
 
-#ifdef CONFIG_ARM
-	/*
-	 * PCIe access errors that result into OCP errors are caught by ARM as
-	 * "External aborts"
-	 */
-	hook_fault_code(17, ks_pcie_fault, SIGBUS, 0,
-			"Asynchronous external abort");
-#endif
-
 	return 0;
 }
 
@@ -1134,6 +1126,7 @@ static const struct of_device_id ks_pcie_of_match[] = {
 	},
 	{ },
 };
+MODULE_DEVICE_TABLE(of, ks_pcie_of_match);
 
 static int ks_pcie_probe(struct platform_device *pdev)
 {
@@ -1381,4 +1374,23 @@ static struct platform_driver ks_pcie_driver = {
 		.of_match_table = ks_pcie_of_match,
 	},
 };
-builtin_platform_driver(ks_pcie_driver);
+
+static int __init ks_pcie_init(void)
+{
+#ifdef CONFIG_ARM
+	/*
+	 * PCIe access errors that result into OCP errors are caught by ARM as
+	 * "External aborts"
+	 */
+	if (of_find_matching_node(NULL, ks_pcie_of_match))
+		hook_fault_code(17, ks_pcie_fault, SIGBUS, 0,
+				"Asynchronous external abort");
+#endif
+
+	return platform_driver_register(&ks_pcie_driver);
+}
+device_initcall(ks_pcie_init);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("PCIe host controller driver for Texas Instruments Keystone SoCs");
+MODULE_AUTHOR("Murali Karicheri <m-karicheri2@ti.com>");
-- 
2.51.0

Re: [PATCH v4 4/4] PCI: keystone: Add support to build as a loadable module

[kernel test robot]

Hi Siddharth,

kernel test robot noticed the following build errors:

[auto build test ERROR on pci/next]
[also build test ERROR on pci/for-linus linus/master v6.18-rc3 next-20251027]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Siddharth-Vadapalli/PCI-Export-pci_get_host_bridge_device-for-use-by-pci-keystone/20251022-180213
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
patch link:    https://lore.kernel.org/r/20251022095724.997218-5-s-vadapalli%40ti.com
patch subject: [PATCH v4 4/4] PCI: keystone: Add support to build as a loadable module
config: arm-allmodconfig (https://download.01.org/0day-ci/archive/20251028/202510281008.jw19XuyP-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 15.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251028/202510281008.jw19XuyP-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202510281008.jw19XuyP-lkp@intel.com/

All errors (new ones prefixed by >>, old ones prefixed by <<):

WARNING: modpost: missing MODULE_DESCRIPTION() in arch/arm/probes/kprobes/test-kprobes.o
>> ERROR: modpost: "hook_fault_code" [drivers/pci/controller/dwc/pci-keystone.ko] undefined!
ERROR: modpost: "__ffsdi2" [drivers/spi/spi-amlogic-spifc-a4.ko] undefined!

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v4 4/4] PCI: keystone: Add support to build as a loadable module

[Siddharth Vadapalli]

On Tue, 2025-10-28 at 11:06 +0800, kernel test robot wrote:
> Hi Siddharth,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on pci/next]
> [also build test ERROR on pci/for-linus linus/master v6.18-rc3 next-20251027]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Siddharth-Vadapalli/PCI-Export-pci_get_host_bridge_device-for-use-by-pci-keystone/20251022-180213
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
> patch link:    https://lore.kernel.org/r/20251022095724.997218-5-s-vadapalli%40ti.com
> patch subject: [PATCH v4 4/4] PCI: keystone: Add support to build as a loadable module
> config: arm-allmodconfig (https://download.01.org/0day-ci/archive/20251028/202510281008.jw19XuyP-lkp@intel.com/config)
> compiler: arm-linux-gnueabi-gcc (GCC) 15.1.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251028/202510281008.jw19XuyP-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> > Reported-by: kernel test robot <lkp@intel.com>
> > Closes: https://lore.kernel.org/oe-kbuild-all/202510281008.jw19XuyP-lkp@intel.com/
> 
> All errors (new ones prefixed by >>, old ones prefixed by <<):
> 
> WARNING: modpost: missing MODULE_DESCRIPTION() in arch/arm/probes/kprobes/test-kprobes.o
> > > ERROR: modpost: "hook_fault_code" [drivers/pci/controller/dwc/pci-keystone.ko] undefined!
> ERROR: modpost: "__ffsdi2" [drivers/spi/spi-amlogic-spifc-a4.ko] undefined!

I had built the driver for ARM64 platforms but missed building it for ARM32
platforms. I will fix the build error for ARM32 platforms and will post the
v5 series.

Regards,
Siddharth.

Re: [PATCH v4 4/4] PCI: keystone: Add support to build as a loadable module

[Siddharth Vadapalli]

On Tue, 2025-10-28 at 10:24 +0530, Siddharth Vadapalli wrote:
> On Tue, 2025-10-28 at 11:06 +0800, kernel test robot wrote:
> > Hi Siddharth,
> > 
> > kernel test robot noticed the following build errors:
> > 
> > [auto build test ERROR on pci/next]
> > [also build test ERROR on pci/for-linus linus/master v6.18-rc3 next-20251027]
> > [If your patch is applied to the wrong git tree, kindly drop us a note.
> > And when submitting patch, we suggest to use '--base' as documented in
> > https://git-scm.com/docs/git-format-patch#_base_tree_information]
> > 
> > url:    https://github.com/intel-lab-lkp/linux/commits/Siddharth-Vadapalli/PCI-Export-pci_get_host_bridge_device-for-use-by-pci-keystone/20251022-180213
> > base:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
> > patch link:    https://lore.kernel.org/r/20251022095724.997218-5-s-vadapalli%40ti.com
> > patch subject: [PATCH v4 4/4] PCI: keystone: Add support to build as a loadable module
> > config: arm-allmodconfig (https://download.01.org/0day-ci/archive/20251028/202510281008.jw19XuyP-lkp@intel.com/config)
> > compiler: arm-linux-gnueabi-gcc (GCC) 15.1.0
> > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251028/202510281008.jw19XuyP-lkp@intel.com/reproduce)
> > 
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > > Reported-by: kernel test robot <lkp@intel.com>
> > > Closes: https://lore.kernel.org/oe-kbuild-all/202510281008.jw19XuyP-lkp@intel.com/
> > 
> > All errors (new ones prefixed by >>, old ones prefixed by <<):
> > 
> > WARNING: modpost: missing MODULE_DESCRIPTION() in arch/arm/probes/kprobes/test-kprobes.o
> > > > ERROR: modpost: "hook_fault_code" [drivers/pci/controller/dwc/pci-keystone.ko] undefined!
> > ERROR: modpost: "__ffsdi2" [drivers/spi/spi-amlogic-spifc-a4.ko] undefined!
> 
> I had built the driver for ARM64 platforms but missed building it for ARM32
> platforms. I will fix the build error for ARM32 platforms and will post the
> v5 series.

I have posted the v5 series addressing the above at:
https://lore.kernel.org/r/20251029080547.1253757-1-s-vadapalli@ti.com/

Regards,
Siddharth.