Linux PCI subsystem development
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From: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
To: linux-pci@vger.kernel.org, "Bjorn Helgaas" <bhelgaas@google.com>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Christian König" <christian.koenig@amd.com>,
	"Michał Winiarski" <michal.winiarski@intel.com>,
	"Alex Deucher" <alexander.deucher@amd.com>,
	amd-gfx@lists.freedesktop.org, "David Airlie" <airlied@gmail.com>,
	dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org,
	intel-xe@lists.freedesktop.org,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	"Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>,
	"Lucas De Marchi" <lucas.demarchi@intel.com>,
	"Rodrigo Vivi" <rodrigo.vivi@intel.com>,
	"Simona Vetter" <simona@ffwll.ch>,
	"Tvrtko Ursulin" <tursulin@ursulin.net>,
	?UTF-8?q?Thomas=20Hellstr=C3=B6m?=
	<thomas.hellstrom@linux.intel.com>,
	linux-kernel@vger.kernel.org
Cc: linux-doc@vger.kernel.org,
	"Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
Subject: [PATCH 02/11] PCI: Cleanup pci_rebar_bytes_to_size() and move into rebar.c
Date: Thu, 11 Sep 2025 10:55:56 +0300	[thread overview]
Message-ID: <20250911075605.5277-3-ilpo.jarvinen@linux.intel.com> (raw)
In-Reply-To: <20250911075605.5277-1-ilpo.jarvinen@linux.intel.com>

Move pci_rebar_bytes_to_size() from include/linux/pci.h into rebar.c as
it does not look very trivial and is not expected to be performance
critical.

Convert literals to use a newly added PCI_REBAR_MIN_SIZE define.

Also add kernel doc for the function as the function is exported.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 drivers/pci/rebar.c | 23 +++++++++++++++++++++++
 include/linux/pci.h | 10 +++-------
 2 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/rebar.c b/drivers/pci/rebar.c
index b87cfa6fb3ef..961bd43be02b 100644
--- a/drivers/pci/rebar.c
+++ b/drivers/pci/rebar.c
@@ -7,11 +7,34 @@
 #include <linux/errno.h>
 #include <linux/export.h>
 #include <linux/ioport.h>
+#include <linux/log2.h>
 #include <linux/pci.h>
+#include <linux/sizes.h>
 #include <linux/types.h>
 
 #include "pci.h"
 
+#define PCI_REBAR_MIN_SIZE	((resource_size_t)SZ_1M)
+
+/**
+ * pci_rebar_bytes_to_size - Convert size in bytes to PCI BAR Size
+ * @bytes: size in bytes
+ *
+ * Convert bytes to BAR Size in Resizable BAR Capability (PCIe r6.2,
+ * sec. 7.8.6.3).
+ *
+ * Return: BAR Size as defined in the PCIe spec (0=1MB, bit 31=128TB).
+ */
+int pci_rebar_bytes_to_size(u64 bytes)
+{
+	int rebar_minsize = ilog2(PCI_REBAR_MIN_SIZE);
+
+	bytes = roundup_pow_of_two(bytes);
+
+	return max(ilog2(bytes), rebar_minsize) - rebar_minsize;
+}
+EXPORT_SYMBOL_GPL(pci_rebar_bytes_to_size);
+
 void pci_rebar_init(struct pci_dev *pdev)
 {
 	pdev->rebar_cap = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_REBAR);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 59876de13860..894e9020b07d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1418,16 +1418,12 @@ void pcibios_reset_secondary_bus(struct pci_dev *dev);
 void pci_update_resource(struct pci_dev *dev, int resno);
 int __must_check pci_assign_resource(struct pci_dev *dev, int i);
 void pci_release_resource(struct pci_dev *dev, int resno);
-static inline int pci_rebar_bytes_to_size(u64 bytes)
-{
-	bytes = roundup_pow_of_two(bytes);
-
-	/* Return BAR size as defined in the resizable BAR specification */
-	return max(ilog2(bytes), 20) - 20;
-}
 
+/* Resizable BAR related routines */
+int pci_rebar_bytes_to_size(u64 bytes);
 u32 pci_rebar_get_possible_sizes(struct pci_dev *pdev, int bar);
 int __must_check pci_resize_resource(struct pci_dev *dev, int i, int size);
+
 int pci_select_bars(struct pci_dev *dev, unsigned long flags);
 bool pci_device_is_present(struct pci_dev *pdev);
 void pci_ignore_hotplug(struct pci_dev *dev);
-- 
2.39.5


  parent reply	other threads:[~2025-09-11  7:56 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-11  7:55 [PATCH 00/11] PCI: Resizable BAR improvements Ilpo Järvinen
2025-09-11  7:55 ` [PATCH 01/11] PCI: Move Resizable BAR code into rebar.c Ilpo Järvinen
2025-09-11  7:55 ` Ilpo Järvinen [this message]
2025-09-11 17:25   ` [PATCH 02/11] PCI: Cleanup pci_rebar_bytes_to_size() and move " Ruhl, Michael J
2025-09-11  7:55 ` [PATCH 03/11] PCI: Move pci_rebar_size_to_bytes() and export it Ilpo Järvinen
2025-09-11  7:55 ` [PATCH 04/11] PCI: Improve Resizable BAR functions kernel doc Ilpo Järvinen
2025-09-11  8:24   ` Christian König
2025-09-11  8:59     ` Ilpo Järvinen
2025-09-11  9:08       ` Christian König
2025-09-11 20:58   ` Randy Dunlap
2025-09-11  7:55 ` [PATCH 05/11] PCI: Add pci_rebar_size_supported() helper Ilpo Järvinen
2025-09-11  8:27   ` Christian König
2025-09-11  7:56 ` [PATCH 06/11] drm/i915/gt: Use pci_rebar_size_supported() Ilpo Järvinen
2025-09-11  7:56 ` [PATCH 07/11] drm/xe/vram: Use PCI rebar helpers in resize_vram_bar() Ilpo Järvinen
2025-09-11  7:56 ` [PATCH 08/11] PCI: Add pci_rebar_get_max_size() Ilpo Järvinen
2025-09-11  7:56 ` [PATCH 09/11] drm/xe/vram: Use pci_rebar_get_max_size() Ilpo Järvinen
2025-09-11  7:56 ` [PATCH 10/11] drm/amdgpu: " Ilpo Järvinen
2025-09-11  7:56 ` [PATCH 11/11] PCI: Convert BAR sizes bitmasks to u64 Ilpo Järvinen
2025-09-11  8:35 ` [PATCH 00/11] PCI: Resizable BAR improvements Christian König

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