* [PATCH v2 1/3] mtd: core: add get_mtd_device_by_node
2018-09-07 17:35 [PATCH v2 0/3] mtd concat device driver Bernhard Frauendienst
@ 2018-09-07 17:35 ` Bernhard Frauendienst
2018-09-07 18:12 ` [PATCH v2 0/3] mtd concat device driver Bernhard Frauendienst
2018-09-07 17:35 ` [PATCH v2 2/3] dt-bindings: add bindings for mtd-concat devices Bernhard Frauendienst
2018-09-07 17:35 ` [PATCH v2 3/3] mtd: mtdconcat: add dt driver for concat devices Bernhard Frauendienst
2 siblings, 1 reply; 6+ messages in thread
From: Bernhard Frauendienst @ 2018-09-07 17:35 UTC (permalink / raw)
To: David Woodhouse, Brian Norris, Boris Brezillon, Marek Vasut,
Richard Weinberger
Cc: Miquel Raynal, linux-mtd, linux-kernel
Add function to retrieve a mtd device by its OF node. Since drivers can
assign arbitrary names to mtd devices in the absence of a label
property, there is no other reliable way to retrieve a mtd device for a
given OF node.
Signed-off-by: Bernhard Frauendienst <kernel@nospam.obeliks.de>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
drivers/mtd/mtdcore.c | 38 ++++++++++++++++++++++++++++++++++++++
include/linux/mtd/mtd.h | 2 ++
2 files changed, 40 insertions(+)
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 97ac219c082e..87dd63926bc9 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -926,6 +926,44 @@ struct mtd_info *get_mtd_device_nm(const char *name)
}
EXPORT_SYMBOL_GPL(get_mtd_device_nm);
+/**
+ * get_mtd_device_by_node - obtain a validated handle for an MTD device
+ * by of_node
+ * @of_node: OF node of MTD device to open
+ *
+ * This function returns MTD device description structure in case of
+ * success and an error code in case of failure.
+ */
+struct mtd_info *get_mtd_device_by_node(const struct device_node *of_node)
+{
+ int err = -ENODEV;
+ struct mtd_info *mtd = NULL, *other;
+
+ mutex_lock(&mtd_table_mutex);
+
+ mtd_for_each_device(other) {
+ if (of_node == other->dev.of_node) {
+ mtd = other;
+ break;
+ }
+ }
+
+ if (!mtd)
+ goto out_unlock;
+
+ err = __get_mtd_device(mtd);
+ if (err)
+ goto out_unlock;
+
+ mutex_unlock(&mtd_table_mutex);
+ return mtd;
+
+out_unlock:
+ mutex_unlock(&mtd_table_mutex);
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(get_mtd_device_by_node);
+
void put_mtd_device(struct mtd_info *mtd)
{
mutex_lock(&mtd_table_mutex);
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index cd0be91bdefa..fe71358f8eaa 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -570,6 +570,8 @@ extern struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num);
extern int __get_mtd_device(struct mtd_info *mtd);
extern void __put_mtd_device(struct mtd_info *mtd);
extern struct mtd_info *get_mtd_device_nm(const char *name);
+extern struct mtd_info *get_mtd_device_by_node(
+ const struct device_node *of_node);
extern void put_mtd_device(struct mtd_info *mtd);
--
2.17.1
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH v2 2/3] dt-bindings: add bindings for mtd-concat devices
2018-09-07 17:35 [PATCH v2 0/3] mtd concat device driver Bernhard Frauendienst
2018-09-07 17:35 ` [PATCH v2 1/3] mtd: core: add get_mtd_device_by_node Bernhard Frauendienst
@ 2018-09-07 17:35 ` Bernhard Frauendienst
2018-09-07 17:35 ` [PATCH v2 3/3] mtd: mtdconcat: add dt driver for concat devices Bernhard Frauendienst
2 siblings, 0 replies; 6+ messages in thread
From: Bernhard Frauendienst @ 2018-09-07 17:35 UTC (permalink / raw)
To: David Woodhouse, Brian Norris, Boris Brezillon, Marek Vasut,
Richard Weinberger
Cc: Miquel Raynal, Rob Herring, Mark Rutland, linux-mtd, devicetree,
linux-kernel
Signed-off-by: Bernhard Frauendienst <kernel@nospam.obeliks.de>
---
.../devicetree/bindings/mtd/mtd-concat.txt | 36 +++++++++++++++++++
1 file changed, 36 insertions(+)
create mode 100644 Documentation/devicetree/bindings/mtd/mtd-concat.txt
diff --git a/Documentation/devicetree/bindings/mtd/mtd-concat.txt b/Documentation/devicetree/bindings/mtd/mtd-concat.txt
new file mode 100644
index 000000000000..2daf3157b163
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/mtd-concat.txt
@@ -0,0 +1,36 @@
+Virtual MTD concat device
+
+Requires properties:
+- devices: list of phandles to mtd nodes that should be concatenated
+
+Example:
+
+&spi {
+ flash0: flash@0 {
+ ...
+ };
+ flash1: flash@1 {
+ ...
+ };
+};
+
+flash {
+ compatible = "mtd-concat";
+
+ devices = <&flash0 &flash1>;
+
+ partitions {
+ compatible = "fixed-partitions";
+
+ partition@0 {
+ label = "boot";
+ reg = <0x0000000 0x0040000>;
+ read-only;
+ };
+
+ partition@40000 {
+ label = "firmware";
+ reg = <0x0040000 0x1fc0000>;
+ };
+ }
+}
--
2.17.1
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH v2 3/3] mtd: mtdconcat: add dt driver for concat devices
2018-09-07 17:35 [PATCH v2 0/3] mtd concat device driver Bernhard Frauendienst
2018-09-07 17:35 ` [PATCH v2 1/3] mtd: core: add get_mtd_device_by_node Bernhard Frauendienst
2018-09-07 17:35 ` [PATCH v2 2/3] dt-bindings: add bindings for mtd-concat devices Bernhard Frauendienst
@ 2018-09-07 17:35 ` Bernhard Frauendienst
2 siblings, 0 replies; 6+ messages in thread
From: Bernhard Frauendienst @ 2018-09-07 17:35 UTC (permalink / raw)
To: David Woodhouse, Brian Norris, Boris Brezillon, Marek Vasut,
Richard Weinberger
Cc: Miquel Raynal, linux-kernel, linux-mtd
Some mtd drivers like physmap variants have support for concatenating
multiple mtd devices, but there is no generic way to define such a
concat device from within the device tree.
This is useful for some SoC boards that use multiple flash chips as
memory banks of a single mtd device, with partitions spanning chip
borders.
This commit adds a driver for creating virtual mtd-concat devices. They
must have a compatible = "mtd-concat" line, and define a list of devices
to concat in the 'devices' property, for example:
flash {
compatible = "mtd-concat";
devices = <&flash0 &flash1>;
partitions {
...
};
};
The driver is added to the very end of the mtd Makefile to increase the
likelyhood of all child devices already being loaded at the time of
probing, preventing unnecessary deferred probes.
Signed-off-by: Bernhard Frauendienst <kernel@nospam.obeliks.de>
---
drivers/mtd/Kconfig | 2 +
drivers/mtd/Makefile | 3 +
drivers/mtd/composite/Kconfig | 12 +++
drivers/mtd/composite/Makefile | 7 ++
drivers/mtd/composite/virt_concat.c | 128 ++++++++++++++++++++++++++++
5 files changed, 152 insertions(+)
create mode 100644 drivers/mtd/composite/Kconfig
create mode 100644 drivers/mtd/composite/Makefile
create mode 100644 drivers/mtd/composite/virt_concat.c
diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index c77f537323ec..6345d886d458 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -339,4 +339,6 @@ source "drivers/mtd/spi-nor/Kconfig"
source "drivers/mtd/ubi/Kconfig"
+source "drivers/mtd/composite/Kconfig"
+
endif # MTD
diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile
index 93473d215a38..57af7190b063 100644
--- a/drivers/mtd/Makefile
+++ b/drivers/mtd/Makefile
@@ -36,3 +36,6 @@ obj-y += chips/ lpddr/ maps/ devices/ nand/ tests/
obj-$(CONFIG_MTD_SPI_NOR) += spi-nor/
obj-$(CONFIG_MTD_UBI) += ubi/
+
+# Composite drivers must be loaded last
+obj-y += composite/
diff --git a/drivers/mtd/composite/Kconfig b/drivers/mtd/composite/Kconfig
new file mode 100644
index 000000000000..0490fc0284bb
--- /dev/null
+++ b/drivers/mtd/composite/Kconfig
@@ -0,0 +1,12 @@
+menu "Composite MTD device drivers"
+ depends on MTD!=n
+
+config MTD_VIRT_CONCAT
+ tristate "Virtual concat MTD device"
+ help
+ This driver allows creation of a virtual MTD concat device, which
+ concatenates multiple underlying MTD devices to a single device.
+ This is required by some SoC boards where multiple memory banks are
+ used as one device with partitions spanning across device boundaries.
+
+endmenu
diff --git a/drivers/mtd/composite/Makefile b/drivers/mtd/composite/Makefile
new file mode 100644
index 000000000000..7f4bdeee0e0a
--- /dev/null
+++ b/drivers/mtd/composite/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# linux/drivers/mtd/composite/Makefile
+#
+
+obj-$(CONFIG_MTD_VIRT_CONCAT) += virt_concat.o
+
diff --git a/drivers/mtd/composite/virt_concat.c b/drivers/mtd/composite/virt_concat.c
new file mode 100644
index 000000000000..76918d4ef07f
--- /dev/null
+++ b/drivers/mtd/composite/virt_concat.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Virtual concat MTD device driver
+ *
+ * Copyright (C) 2018 Bernhard Frauendienst
+ * Author: Bernhard Frauendienst, kernel@nospam.obeliks.de
+ */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/mtd/concat.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/slab.h>
+
+/*
+ * struct of_virt_concat - platform device driver data.
+ * @cmtd the final mtd_concat device
+ * @num_devices the number of devices in @devices
+ * @devices array of devices already loaded
+ */
+struct of_virt_concat {
+ struct mtd_info *cmtd;
+ int num_devices;
+ struct mtd_info **devices;
+};
+
+static int virt_concat_remove(struct platform_device *pdev)
+{
+ struct of_virt_concat *info;
+ int i;
+
+ info = platform_get_drvdata(pdev);
+ if (!info)
+ return 0;
+
+ // unset data for when this is called after a probe error
+ platform_set_drvdata(pdev, NULL);
+
+ if (info->cmtd) {
+ mtd_device_unregister(info->cmtd);
+ mtd_concat_destroy(info->cmtd);
+ }
+
+ if (info->devices) {
+ for (i = 0; i < info->num_devices; i++)
+ put_mtd_device(info->devices[i]);
+ }
+
+ return 0;
+}
+
+static int virt_concat_probe(struct platform_device *pdev)
+{
+ struct device_node *node = pdev->dev.of_node;
+ struct of_phandle_iterator it;
+ struct of_virt_concat *info;
+ struct mtd_info *mtd;
+ int err = 0, count;
+
+ count = of_count_phandle_with_args(node, "devices", NULL);
+ if (count <= 0)
+ return -EINVAL;
+
+ info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+ info->devices = devm_kcalloc(&pdev->dev, count,
+ sizeof(*(info->devices)), GFP_KERNEL);
+ if (!info->devices) {
+ err = -ENOMEM;
+ goto err_remove;
+ }
+
+ platform_set_drvdata(pdev, info);
+
+ of_for_each_phandle(&it, err, node, "devices", NULL, 0) {
+ mtd = get_mtd_device_by_node(it.node);
+ if (IS_ERR(mtd)) {
+ of_node_put(it.node);
+ err = -EPROBE_DEFER;
+ goto err_remove;
+ }
+
+ info->devices[info->num_devices++] = mtd;
+ }
+
+ info->cmtd = mtd_concat_create(info->devices, info->num_devices,
+ dev_name(&pdev->dev));
+ if (!info->cmtd) {
+ err = -ENXIO;
+ goto err_remove;
+ }
+
+ info->cmtd->dev.parent = &pdev->dev;
+ mtd_set_of_node(info->cmtd, node);
+ mtd_device_register(info->cmtd, NULL, 0);
+
+ return 0;
+
+err_remove:
+ virt_concat_remove(pdev);
+
+ return err;
+}
+
+static const struct of_device_id virt_concat_of_match[] = {
+ { .compatible = "mtd-concat", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, virt_concat_of_match);
+
+static struct platform_driver virt_concat_driver = {
+ .probe = virt_concat_probe,
+ .remove = virt_concat_remove,
+ .driver = {
+ .name = "virt-mtdconcat",
+ .of_match_table = virt_concat_of_match,
+ },
+};
+
+module_platform_driver(virt_concat_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Bernhard Frauendienst <kernel@nospam.obeliks.de>");
+MODULE_DESCRIPTION("Virtual concat MTD device driver");
--
2.17.1
^ permalink raw reply [flat|nested] 6+ messages in thread