diff mbox series

[3/4] pci: move devres code from pci.c to devres.c

Message ID 20231120215945.52027-5-pstanner@redhat.com
State New
Headers show
Series Regather scattered PCI-Code | expand

Commit Message

Philipp Stanner Nov. 20, 2023, 9:59 p.m. UTC 
The file pci.c is very large and contains a number of devres-functions.
These functions should now reside in devres.c

There are a few callers left in pci.c that do devres operations. These
should be ported in the future. Corresponding TODOs are added by this
commit.

The reason they are not moved right now in this commit is that pci's
devres currently implements a sort of "hybrid-mode":
pci_request_region(), for instance, does not have a corresponding pcim_
equivalent, yet. Instead, the function can be made managed by previously
calling pcim_enable_device() (instead of pci_enable_device()). This
makes it unreasonable to move pci_request_region() to devres.c
Moving the functions would require changes to pci's API and is,
therefore, left for future work.

Move as much devres-specific code from pci.c to devres.c as possible.

Suggested-by: Danilo Krummrich <dakr@redhat.com>
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
---
 drivers/pci/devres.c | 243 +++++++++++++++++++++++++++++++++++++++++
 drivers/pci/pci.c    | 249 -------------------------------------------
 drivers/pci/pci.h    |  24 +++++
 3 files changed, 267 insertions(+), 249 deletions(-)

Comments

Arnd Bergmann Nov. 21, 2023, 10:17 a.m. UTC | #1 
On Mon, Nov 20, 2023, at 22:59, Philipp Stanner wrote:
> The file pci.c is very large and contains a number of devres-functions.
> These functions should now reside in devres.c
>
> There are a few callers left in pci.c that do devres operations. These
> should be ported in the future. Corresponding TODOs are added by this
> commit.
>
> The reason they are not moved right now in this commit is that pci's
> devres currently implements a sort of "hybrid-mode":
> pci_request_region(), for instance, does not have a corresponding pcim_
> equivalent, yet. Instead, the function can be made managed by previously
> calling pcim_enable_device() (instead of pci_enable_device()). This
> makes it unreasonable to move pci_request_region() to devres.c
> Moving the functions would require changes to pci's API and is,
> therefore, left for future work.
>
> Move as much devres-specific code from pci.c to devres.c as possible.
>
> Suggested-by: Danilo Krummrich <dakr@redhat.com>
> Signed-off-by: Philipp Stanner <pstanner@redhat.com>
> ---
>  drivers/pci/devres.c | 243 +++++++++++++++++++++++++++++++++++++++++
>  drivers/pci/pci.c    | 249 -------------------------------------------
>  drivers/pci/pci.h    |  24 +++++
>  3 files changed, 267 insertions(+), 249 deletions(-)

I had just commented in the other mail that you'd have to move
these functions to devres.c for the file to make sense, but that
I think the existing state is better.

Just to clarify again here: this patch does not seem to improve
anything to me, I'd much prefer leaving it the way it is, and
moving the pcim_iomap family to corresponding drivers/pci/iomap.c. 

     Arnd
Philipp Stanner Nov. 21, 2023, 10:36 a.m. UTC | #2 
On Tue, 2023-11-21 at 11:17 +0100, Arnd Bergmann wrote:
> On Mon, Nov 20, 2023, at 22:59, Philipp Stanner wrote:
> > The file pci.c is very large and contains a number of devres-
> > functions.
> > These functions should now reside in devres.c
> > 
> > There are a few callers left in pci.c that do devres operations.
> > These
> > should be ported in the future. Corresponding TODOs are added by
> > this
> > commit.
> > 
> > The reason they are not moved right now in this commit is that
> > pci's
> > devres currently implements a sort of "hybrid-mode":
> > pci_request_region(), for instance, does not have a corresponding
> > pcim_
> > equivalent, yet. Instead, the function can be made managed by
> > previously
> > calling pcim_enable_device() (instead of pci_enable_device()). This
> > makes it unreasonable to move pci_request_region() to devres.c
> > Moving the functions would require changes to pci's API and is,
> > therefore, left for future work.
> > 
> > Move as much devres-specific code from pci.c to devres.c as
> > possible.
> > 
> > Suggested-by: Danilo Krummrich <dakr@redhat.com>
> > Signed-off-by: Philipp Stanner <pstanner@redhat.com>
> > ---
> >  drivers/pci/devres.c | 243
> > +++++++++++++++++++++++++++++++++++++++++
> >  drivers/pci/pci.c    | 249 ---------------------------------------
> > ----
> >  drivers/pci/pci.h    |  24 +++++
> >  3 files changed, 267 insertions(+), 249 deletions(-)
> 
> I had just commented in the other mail that you'd have to move
> these functions to devres.c for the file to make sense, but that
> I think the existing state is better.
> 
> Just to clarify again here: this patch does not seem to improve
> anything to me,

Have you read the cover letter? It elaborates on that.

The idea behind centralizing devres-pci-code in a separate file is that
the current implementation is strangely torn.
My mid-term goal would be to fix that, but that's beyond the scope of
this series.

PCI has some separate devres functions, prefixed with pcim_ – and then
there are some other functions that use a crazy hybrid mode:

drivers/pci/pci.c:

void pci_release_region(struct pci_dev *pdev, int bar)
{
	/* ..... SNIP ......... */

 dr = find_pci_dr(pdev);
 if (dr)
 dr->region_mask &= ~(1 << bar);
}

Some functions without pcim_ prefix switch to managed mode if
pcim_enable_device() instead of pci_enable_device() was called.

So some functions are sometimes managed and others never are, which is
totally inconsistent.

This is bug-provoking because programmers won't know without looking
very closely which functions become managed and which don't.

That should be fixed. And a first step towards that goal is to cleanly
split them. Everything managed should reside, on the long term, in
drivers/pci/devres.c

>  I'd much prefer leaving it the way it is, and
> moving the pcim_iomap family to corresponding drivers/pci/iomap.c. 

We could branch that change out of the patch series and handle the
topics independently

P.

> 
>      Arnd
>
diff mbox series

Patch

diff --git a/drivers/pci/devres.c b/drivers/pci/devres.c
index a3fd0d65cef1..55f76a2c3748 100644
--- a/drivers/pci/devres.c
+++ b/drivers/pci/devres.c
@@ -1,4 +1,5 @@ 
 // SPDX-License-Identifier: GPL-2.0
+#include <linux/device.h>
 #include <linux/pci.h>
 #include "pci.h"
 
@@ -11,6 +12,248 @@  struct pcim_iomap_devres {
 	void __iomem *table[PCIM_IOMAP_MAX];
 };
 
+
+static void devm_pci_unmap_iospace(struct device *dev, void *ptr)
+{
+	struct resource **res = ptr;
+
+	pci_unmap_iospace(*res);
+}
+
+/**
+ * devm_pci_remap_iospace - Managed pci_remap_iospace()
+ * @dev: Generic device to remap IO address for
+ * @res: Resource describing the I/O space
+ * @phys_addr: physical address of range to be mapped
+ *
+ * Managed pci_remap_iospace().  Map is automatically unmapped on driver
+ * detach.
+ */
+int devm_pci_remap_iospace(struct device *dev, const struct resource *res,
+			   phys_addr_t phys_addr)
+{
+	const struct resource **ptr;
+	int error;
+
+	ptr = devres_alloc(devm_pci_unmap_iospace, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	error = pci_remap_iospace(res, phys_addr);
+	if (error) {
+		devres_free(ptr);
+	} else	{
+		*ptr = res;
+		devres_add(dev, ptr);
+	}
+
+	return error;
+}
+EXPORT_SYMBOL(devm_pci_remap_iospace);
+
+/**
+ * devm_pci_remap_cfgspace - Managed pci_remap_cfgspace()
+ * @dev: Generic device to remap IO address for
+ * @offset: Resource address to map
+ * @size: Size of map
+ *
+ * Managed pci_remap_cfgspace().  Map is automatically unmapped on driver
+ * detach.
+ */
+void __iomem *devm_pci_remap_cfgspace(struct device *dev,
+				      resource_size_t offset,
+				      resource_size_t size)
+{
+	void __iomem **ptr, *addr;
+
+	ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return NULL;
+
+	addr = pci_remap_cfgspace(offset, size);
+	if (addr) {
+		*ptr = addr;
+		devres_add(dev, ptr);
+	} else
+		devres_free(ptr);
+
+	return addr;
+}
+EXPORT_SYMBOL(devm_pci_remap_cfgspace);
+
+/**
+ * devm_pci_remap_cfg_resource - check, request region and ioremap cfg resource
+ * @dev: generic device to handle the resource for
+ * @res: configuration space resource to be handled
+ *
+ * Checks that a resource is a valid memory region, requests the memory
+ * region and ioremaps with pci_remap_cfgspace() API that ensures the
+ * proper PCI configuration space memory attributes are guaranteed.
+ *
+ * All operations are managed and will be undone on driver detach.
+ *
+ * Returns a pointer to the remapped memory or an ERR_PTR() encoded error code
+ * on failure. Usage example::
+ *
+ *	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ *	base = devm_pci_remap_cfg_resource(&pdev->dev, res);
+ *	if (IS_ERR(base))
+ *		return PTR_ERR(base);
+ */
+void __iomem *devm_pci_remap_cfg_resource(struct device *dev,
+					  struct resource *res)
+{
+	resource_size_t size;
+	const char *name;
+	void __iomem *dest_ptr;
+
+	BUG_ON(!dev);
+
+	if (!res || resource_type(res) != IORESOURCE_MEM) {
+		dev_err(dev, "invalid resource\n");
+		return IOMEM_ERR_PTR(-EINVAL);
+	}
+
+	size = resource_size(res);
+
+	if (res->name)
+		name = devm_kasprintf(dev, GFP_KERNEL, "%s %s", dev_name(dev),
+				      res->name);
+	else
+		name = devm_kstrdup(dev, dev_name(dev), GFP_KERNEL);
+	if (!name)
+		return IOMEM_ERR_PTR(-ENOMEM);
+
+	if (!devm_request_mem_region(dev, res->start, size, name)) {
+		dev_err(dev, "can't request region for resource %pR\n", res);
+		return IOMEM_ERR_PTR(-EBUSY);
+	}
+
+	dest_ptr = devm_pci_remap_cfgspace(dev, res->start, size);
+	if (!dest_ptr) {
+		dev_err(dev, "ioremap failed for resource %pR\n", res);
+		devm_release_mem_region(dev, res->start, size);
+		dest_ptr = IOMEM_ERR_PTR(-ENOMEM);
+	}
+
+	return dest_ptr;
+}
+EXPORT_SYMBOL(devm_pci_remap_cfg_resource);
+
+/**
+ * pcim_set_mwi - a device-managed pci_set_mwi()
+ * @dev: the PCI device for which MWI is enabled
+ *
+ * Managed pci_set_mwi().
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int pcim_set_mwi(struct pci_dev *dev)
+{
+	struct pci_devres *dr;
+
+	dr = find_pci_dr(dev);
+	if (!dr)
+		return -ENOMEM;
+
+	dr->mwi = 1;
+	return pci_set_mwi(dev);
+}
+EXPORT_SYMBOL(pcim_set_mwi);
+
+
+static void pcim_release(struct device *gendev, void *res)
+{
+	struct pci_dev *dev = to_pci_dev(gendev);
+	struct pci_devres *this = res;
+	int i;
+
+	for (i = 0; i < DEVICE_COUNT_RESOURCE; i++)
+		if (this->region_mask & (1 << i))
+			pci_release_region(dev, i);
+
+	if (this->mwi)
+		pci_clear_mwi(dev);
+
+	if (this->restore_intx)
+		pci_intx(dev, this->orig_intx);
+
+	if (this->enabled && !this->pinned)
+		pci_disable_device(dev);
+}
+
+/*
+ * TODO:
+ * Once the last four callers in pci.c are ported, this function here needs to
+ * be made static again.
+ */
+struct pci_devres *find_pci_dr(struct pci_dev *pdev)
+{
+	if (pci_is_managed(pdev))
+		return devres_find(&pdev->dev, pcim_release, NULL, NULL);
+	return NULL;
+}
+EXPORT_SYMBOL(find_pci_dr); // TODO do we need this?
+
+static struct pci_devres *get_pci_dr(struct pci_dev *pdev)
+{
+	struct pci_devres *dr, *new_dr;
+
+	dr = devres_find(&pdev->dev, pcim_release, NULL, NULL);
+	if (dr)
+		return dr;
+
+	new_dr = devres_alloc(pcim_release, sizeof(*new_dr), GFP_KERNEL);
+	if (!new_dr)
+		return NULL;
+	return devres_get(&pdev->dev, new_dr, NULL, NULL);
+}
+
+/**
+ * pcim_enable_device - Managed pci_enable_device()
+ * @pdev: PCI device to be initialized
+ *
+ * Managed pci_enable_device().
+ */
+int pcim_enable_device(struct pci_dev *pdev)
+{
+	struct pci_devres *dr;
+	int rc;
+
+	dr = get_pci_dr(pdev);
+	if (unlikely(!dr))
+		return -ENOMEM;
+	if (dr->enabled)
+		return 0;
+
+	rc = pci_enable_device(pdev);
+	if (!rc) {
+		pdev->is_managed = 1;
+		dr->enabled = 1;
+	}
+	return rc;
+}
+EXPORT_SYMBOL(pcim_enable_device);
+
+/**
+ * pcim_pin_device - Pin managed PCI device
+ * @pdev: PCI device to pin
+ *
+ * Pin managed PCI device @pdev.  Pinned device won't be disabled on
+ * driver detach.  @pdev must have been enabled with
+ * pcim_enable_device().
+ */
+void pcim_pin_device(struct pci_dev *pdev)
+{
+	struct pci_devres *dr;
+
+	dr = find_pci_dr(pdev);
+	WARN_ON(!dr || !dr->enabled);
+	if (dr)
+		dr->pinned = 1;
+}
+EXPORT_SYMBOL(pcim_pin_device);
+
 static void pcim_iomap_release(struct device *gendev, void *res)
 {
 	struct pci_dev *dev = to_pci_dev(gendev);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 55bc3576a985..742b0a6545b6 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2088,107 +2088,6 @@  int pci_enable_device(struct pci_dev *dev)
 }
 EXPORT_SYMBOL(pci_enable_device);
 
-/*
- * Managed PCI resources.  This manages device on/off, INTx/MSI/MSI-X
- * on/off and BAR regions.  pci_dev itself records MSI/MSI-X status, so
- * there's no need to track it separately.  pci_devres is initialized
- * when a device is enabled using managed PCI device enable interface.
- */
-struct pci_devres {
-	unsigned int enabled:1;
-	unsigned int pinned:1;
-	unsigned int orig_intx:1;
-	unsigned int restore_intx:1;
-	unsigned int mwi:1;
-	u32 region_mask;
-};
-
-static void pcim_release(struct device *gendev, void *res)
-{
-	struct pci_dev *dev = to_pci_dev(gendev);
-	struct pci_devres *this = res;
-	int i;
-
-	for (i = 0; i < DEVICE_COUNT_RESOURCE; i++)
-		if (this->region_mask & (1 << i))
-			pci_release_region(dev, i);
-
-	if (this->mwi)
-		pci_clear_mwi(dev);
-
-	if (this->restore_intx)
-		pci_intx(dev, this->orig_intx);
-
-	if (this->enabled && !this->pinned)
-		pci_disable_device(dev);
-}
-
-static struct pci_devres *get_pci_dr(struct pci_dev *pdev)
-{
-	struct pci_devres *dr, *new_dr;
-
-	dr = devres_find(&pdev->dev, pcim_release, NULL, NULL);
-	if (dr)
-		return dr;
-
-	new_dr = devres_alloc(pcim_release, sizeof(*new_dr), GFP_KERNEL);
-	if (!new_dr)
-		return NULL;
-	return devres_get(&pdev->dev, new_dr, NULL, NULL);
-}
-
-static struct pci_devres *find_pci_dr(struct pci_dev *pdev)
-{
-	if (pci_is_managed(pdev))
-		return devres_find(&pdev->dev, pcim_release, NULL, NULL);
-	return NULL;
-}
-
-/**
- * pcim_enable_device - Managed pci_enable_device()
- * @pdev: PCI device to be initialized
- *
- * Managed pci_enable_device().
- */
-int pcim_enable_device(struct pci_dev *pdev)
-{
-	struct pci_devres *dr;
-	int rc;
-
-	dr = get_pci_dr(pdev);
-	if (unlikely(!dr))
-		return -ENOMEM;
-	if (dr->enabled)
-		return 0;
-
-	rc = pci_enable_device(pdev);
-	if (!rc) {
-		pdev->is_managed = 1;
-		dr->enabled = 1;
-	}
-	return rc;
-}
-EXPORT_SYMBOL(pcim_enable_device);
-
-/**
- * pcim_pin_device - Pin managed PCI device
- * @pdev: PCI device to pin
- *
- * Pin managed PCI device @pdev.  Pinned device won't be disabled on
- * driver detach.  @pdev must have been enabled with
- * pcim_enable_device().
- */
-void pcim_pin_device(struct pci_dev *pdev)
-{
-	struct pci_devres *dr;
-
-	dr = find_pci_dr(pdev);
-	WARN_ON(!dr || !dr->enabled);
-	if (dr)
-		dr->pinned = 1;
-}
-EXPORT_SYMBOL(pcim_pin_device);
-
 /*
  * pcibios_device_add - provide arch specific hooks when adding device dev
  * @dev: the PCI device being added
@@ -4281,133 +4180,6 @@  void pci_unmap_iospace(struct resource *res)
 }
 EXPORT_SYMBOL(pci_unmap_iospace);
 
-static void devm_pci_unmap_iospace(struct device *dev, void *ptr)
-{
-	struct resource **res = ptr;
-
-	pci_unmap_iospace(*res);
-}
-
-/**
- * devm_pci_remap_iospace - Managed pci_remap_iospace()
- * @dev: Generic device to remap IO address for
- * @res: Resource describing the I/O space
- * @phys_addr: physical address of range to be mapped
- *
- * Managed pci_remap_iospace().  Map is automatically unmapped on driver
- * detach.
- */
-int devm_pci_remap_iospace(struct device *dev, const struct resource *res,
-			   phys_addr_t phys_addr)
-{
-	const struct resource **ptr;
-	int error;
-
-	ptr = devres_alloc(devm_pci_unmap_iospace, sizeof(*ptr), GFP_KERNEL);
-	if (!ptr)
-		return -ENOMEM;
-
-	error = pci_remap_iospace(res, phys_addr);
-	if (error) {
-		devres_free(ptr);
-	} else	{
-		*ptr = res;
-		devres_add(dev, ptr);
-	}
-
-	return error;
-}
-EXPORT_SYMBOL(devm_pci_remap_iospace);
-
-/**
- * devm_pci_remap_cfgspace - Managed pci_remap_cfgspace()
- * @dev: Generic device to remap IO address for
- * @offset: Resource address to map
- * @size: Size of map
- *
- * Managed pci_remap_cfgspace().  Map is automatically unmapped on driver
- * detach.
- */
-void __iomem *devm_pci_remap_cfgspace(struct device *dev,
-				      resource_size_t offset,
-				      resource_size_t size)
-{
-	void __iomem **ptr, *addr;
-
-	ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL);
-	if (!ptr)
-		return NULL;
-
-	addr = pci_remap_cfgspace(offset, size);
-	if (addr) {
-		*ptr = addr;
-		devres_add(dev, ptr);
-	} else
-		devres_free(ptr);
-
-	return addr;
-}
-EXPORT_SYMBOL(devm_pci_remap_cfgspace);
-
-/**
- * devm_pci_remap_cfg_resource - check, request region and ioremap cfg resource
- * @dev: generic device to handle the resource for
- * @res: configuration space resource to be handled
- *
- * Checks that a resource is a valid memory region, requests the memory
- * region and ioremaps with pci_remap_cfgspace() API that ensures the
- * proper PCI configuration space memory attributes are guaranteed.
- *
- * All operations are managed and will be undone on driver detach.
- *
- * Returns a pointer to the remapped memory or an ERR_PTR() encoded error code
- * on failure. Usage example::
- *
- *	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- *	base = devm_pci_remap_cfg_resource(&pdev->dev, res);
- *	if (IS_ERR(base))
- *		return PTR_ERR(base);
- */
-void __iomem *devm_pci_remap_cfg_resource(struct device *dev,
-					  struct resource *res)
-{
-	resource_size_t size;
-	const char *name;
-	void __iomem *dest_ptr;
-
-	BUG_ON(!dev);
-
-	if (!res || resource_type(res) != IORESOURCE_MEM) {
-		dev_err(dev, "invalid resource\n");
-		return IOMEM_ERR_PTR(-EINVAL);
-	}
-
-	size = resource_size(res);
-
-	if (res->name)
-		name = devm_kasprintf(dev, GFP_KERNEL, "%s %s", dev_name(dev),
-				      res->name);
-	else
-		name = devm_kstrdup(dev, dev_name(dev), GFP_KERNEL);
-	if (!name)
-		return IOMEM_ERR_PTR(-ENOMEM);
-
-	if (!devm_request_mem_region(dev, res->start, size, name)) {
-		dev_err(dev, "can't request region for resource %pR\n", res);
-		return IOMEM_ERR_PTR(-EBUSY);
-	}
-
-	dest_ptr = devm_pci_remap_cfgspace(dev, res->start, size);
-	if (!dest_ptr) {
-		dev_err(dev, "ioremap failed for resource %pR\n", res);
-		devm_release_mem_region(dev, res->start, size);
-		dest_ptr = IOMEM_ERR_PTR(-ENOMEM);
-	}
-
-	return dest_ptr;
-}
-EXPORT_SYMBOL(devm_pci_remap_cfg_resource);
-
 static void __pci_set_master(struct pci_dev *dev, bool enable)
 {
 	u16 old_cmd, cmd;
@@ -4557,27 +4329,6 @@  int pci_set_mwi(struct pci_dev *dev)
 }
 EXPORT_SYMBOL(pci_set_mwi);
 
-/**
- * pcim_set_mwi - a device-managed pci_set_mwi()
- * @dev: the PCI device for which MWI is enabled
- *
- * Managed pci_set_mwi().
- *
- * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
- */
-int pcim_set_mwi(struct pci_dev *dev)
-{
-	struct pci_devres *dr;
-
-	dr = find_pci_dr(dev);
-	if (!dr)
-		return -ENOMEM;
-
-	dr->mwi = 1;
-	return pci_set_mwi(dev);
-}
-EXPORT_SYMBOL(pcim_set_mwi);
-
 /**
  * pci_try_set_mwi - enables memory-write-invalidate PCI transaction
  * @dev: the PCI device for which MWI is enabled
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 5ecbcf041179..69052059dbd2 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -793,6 +793,30 @@  static inline pci_power_t mid_pci_get_power_state(struct pci_dev *pdev)
 }
 #endif
 
+/*
+ * TODO:
+ * The following two components wouldn't need to be here if they weren't used at
+ * four last places in pci.c
+ * Port or move these functions to devres.c and then remove the
+ * pci_devres-components from this header file here.
+ */
+/*
+ * Managed PCI resources.  This manages device on/off, INTx/MSI/MSI-X
+ * on/off and BAR regions.  pci_dev itself records MSI/MSI-X status, so
+ * there's no need to track it separately.  pci_devres is initialized
+ * when a device is enabled using managed PCI device enable interface.
+ */
+struct pci_devres {
+	unsigned int enabled:1;
+	unsigned int pinned:1;
+	unsigned int orig_intx:1;
+	unsigned int restore_intx:1;
+	unsigned int mwi:1;
+	u32 region_mask;
+};
+
+struct pci_devres *find_pci_dr(struct pci_dev *pdev);
+
 /*
  * Config Address for PCI Configuration Mechanism #1
  *