| Message ID | 20181113140133.17385-3-brgl@bgdev.pl (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | at24: remove | expand |
On Tue, 13 Nov 2018 15:01:10 +0100 Bartosz Golaszewski <brgl@bgdev.pl> wrote: > From: Alban Bedel <albeu@free.fr> > > Allow drivers that use the nvmem API to read data stored on MTD devices. > For this the mtd devices are registered as read-only NVMEM providers. > > We don't support device tree systems for now. > > Signed-off-by: Alban Bedel <albeu@free.fr> > [Bartosz: > - include linux/nvmem-provider.h > - set the name of the nvmem provider > - set no_of_node to true in nvmem_config > - don't check the return value of nvmem_unregister() - it cannot fail > - tweaked the commit message] > Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Acked-by: Boris Brezillon <boris.brezillon@bootlin.com> To the person taking this patch (Greg?): I'll need an immutable tag, just in case we end up with other changes in mtdcore.c for this release. > --- > drivers/mtd/Kconfig | 1 + > drivers/mtd/mtdcore.c | 56 +++++++++++++++++++++++++++++++++++++++++ > include/linux/mtd/mtd.h | 2 ++ > 3 files changed, 59 insertions(+) > > diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig > index c77f537323ec..efbe7a6f1d8f 100644 > --- a/drivers/mtd/Kconfig > +++ b/drivers/mtd/Kconfig > @@ -1,5 +1,6 @@ > menuconfig MTD > tristate "Memory Technology Device (MTD) support" > + imply NVMEM > help > Memory Technology Devices are flash, RAM and similar chips, often > used for solid state file systems on embedded devices. This option > diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c > index 97ac219c082e..5f1053d995b0 100644 > --- a/drivers/mtd/mtdcore.c > +++ b/drivers/mtd/mtdcore.c > @@ -41,6 +41,7 @@ > #include <linux/reboot.h> > #include <linux/leds.h> > #include <linux/debugfs.h> > +#include <linux/nvmem-provider.h> > > #include <linux/mtd/mtd.h> > #include <linux/mtd/partitions.h> > @@ -488,6 +489,50 @@ int mtd_pairing_groups(struct mtd_info *mtd) > } > EXPORT_SYMBOL_GPL(mtd_pairing_groups); > > +static int mtd_nvmem_reg_read(void *priv, unsigned int offset, > + void *val, size_t bytes) > +{ > + struct mtd_info *mtd = priv; > + size_t retlen; > + int err; > + > + err = mtd_read(mtd, offset, bytes, &retlen, val); > + if (err && err != -EUCLEAN) > + return err; > + > + return retlen == bytes ? 0 : -EIO; > +} > + > +static int mtd_nvmem_add(struct mtd_info *mtd) > +{ > + struct nvmem_config config = {}; > + > + config.dev = &mtd->dev; > + config.name = mtd->name; > + config.owner = THIS_MODULE; > + config.reg_read = mtd_nvmem_reg_read; > + config.size = mtd->size; > + config.word_size = 1; > + config.stride = 1; > + config.read_only = true; > + config.root_only = true; > + config.no_of_node = true; > + config.priv = mtd; > + > + mtd->nvmem = nvmem_register(&config); > + if (IS_ERR(mtd->nvmem)) { > + /* Just ignore if there is no NVMEM support in the kernel */ > + if (PTR_ERR(mtd->nvmem) == -ENOSYS) { > + mtd->nvmem = NULL; > + } else { > + dev_err(&mtd->dev, "Failed to register NVMEM device\n"); > + return PTR_ERR(mtd->nvmem); > + } > + } > + > + return 0; > +} > + > static struct dentry *dfs_dir_mtd; > > /** > @@ -570,6 +615,11 @@ int add_mtd_device(struct mtd_info *mtd) > if (error) > goto fail_added; > > + /* Add the nvmem provider */ > + error = mtd_nvmem_add(mtd); > + if (error) > + goto fail_nvmem_add; > + > if (!IS_ERR_OR_NULL(dfs_dir_mtd)) { > mtd->dbg.dfs_dir = debugfs_create_dir(dev_name(&mtd->dev), dfs_dir_mtd); > if (IS_ERR_OR_NULL(mtd->dbg.dfs_dir)) { > @@ -595,6 +645,8 @@ int add_mtd_device(struct mtd_info *mtd) > __module_get(THIS_MODULE); > return 0; > > +fail_nvmem_add: > + device_unregister(&mtd->dev); > fail_added: > of_node_put(mtd_get_of_node(mtd)); > idr_remove(&mtd_idr, i); > @@ -637,6 +689,10 @@ int del_mtd_device(struct mtd_info *mtd) > mtd->index, mtd->name, mtd->usecount); > ret = -EBUSY; > } else { > + /* Try to remove the NVMEM provider */ > + if (mtd->nvmem) > + nvmem_unregister(mtd->nvmem); > + > device_unregister(&mtd->dev); > > idr_remove(&mtd_idr, mtd->index); > diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h > index cd0be91bdefa..545070c2ee64 100644 > --- a/include/linux/mtd/mtd.h > +++ b/include/linux/mtd/mtd.h > @@ -25,6 +25,7 @@ > #include <linux/notifier.h> > #include <linux/device.h> > #include <linux/of.h> > +#include <linux/nvmem-provider.h> > > #include <mtd/mtd-abi.h> > > @@ -341,6 +342,7 @@ struct mtd_info { > struct device dev; > int usecount; > struct mtd_debug_info dbg; > + struct nvmem_device *nvmem; > }; > > int mtd_ooblayout_ecc(struct mtd_info *mtd, int section,
diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig index c77f537323ec..efbe7a6f1d8f 100644 --- a/drivers/mtd/Kconfig +++ b/drivers/mtd/Kconfig @@ -1,5 +1,6 @@ menuconfig MTD tristate "Memory Technology Device (MTD) support" + imply NVMEM help Memory Technology Devices are flash, RAM and similar chips, often used for solid state file systems on embedded devices. This option diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index 97ac219c082e..5f1053d995b0 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -41,6 +41,7 @@ #include <linux/reboot.h> #include <linux/leds.h> #include <linux/debugfs.h> +#include <linux/nvmem-provider.h> #include <linux/mtd/mtd.h> #include <linux/mtd/partitions.h> @@ -488,6 +489,50 @@ int mtd_pairing_groups(struct mtd_info *mtd) } EXPORT_SYMBOL_GPL(mtd_pairing_groups); +static int mtd_nvmem_reg_read(void *priv, unsigned int offset, + void *val, size_t bytes) +{ + struct mtd_info *mtd = priv; + size_t retlen; + int err; + + err = mtd_read(mtd, offset, bytes, &retlen, val); + if (err && err != -EUCLEAN) + return err; + + return retlen == bytes ? 0 : -EIO; +} + +static int mtd_nvmem_add(struct mtd_info *mtd) +{ + struct nvmem_config config = {}; + + config.dev = &mtd->dev; + config.name = mtd->name; + config.owner = THIS_MODULE; + config.reg_read = mtd_nvmem_reg_read; + config.size = mtd->size; + config.word_size = 1; + config.stride = 1; + config.read_only = true; + config.root_only = true; + config.no_of_node = true; + config.priv = mtd; + + mtd->nvmem = nvmem_register(&config); + if (IS_ERR(mtd->nvmem)) { + /* Just ignore if there is no NVMEM support in the kernel */ + if (PTR_ERR(mtd->nvmem) == -ENOSYS) { + mtd->nvmem = NULL; + } else { + dev_err(&mtd->dev, "Failed to register NVMEM device\n"); + return PTR_ERR(mtd->nvmem); + } + } + + return 0; +} + static struct dentry *dfs_dir_mtd; /** @@ -570,6 +615,11 @@ int add_mtd_device(struct mtd_info *mtd) if (error) goto fail_added; + /* Add the nvmem provider */ + error = mtd_nvmem_add(mtd); + if (error) + goto fail_nvmem_add; + if (!IS_ERR_OR_NULL(dfs_dir_mtd)) { mtd->dbg.dfs_dir = debugfs_create_dir(dev_name(&mtd->dev), dfs_dir_mtd); if (IS_ERR_OR_NULL(mtd->dbg.dfs_dir)) { @@ -595,6 +645,8 @@ int add_mtd_device(struct mtd_info *mtd) __module_get(THIS_MODULE); return 0; +fail_nvmem_add: + device_unregister(&mtd->dev); fail_added: of_node_put(mtd_get_of_node(mtd)); idr_remove(&mtd_idr, i); @@ -637,6 +689,10 @@ int del_mtd_device(struct mtd_info *mtd) mtd->index, mtd->name, mtd->usecount); ret = -EBUSY; } else { + /* Try to remove the NVMEM provider */ + if (mtd->nvmem) + nvmem_unregister(mtd->nvmem); + device_unregister(&mtd->dev); idr_remove(&mtd_idr, mtd->index); diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h index cd0be91bdefa..545070c2ee64 100644 --- a/include/linux/mtd/mtd.h +++ b/include/linux/mtd/mtd.h @@ -25,6 +25,7 @@ #include <linux/notifier.h> #include <linux/device.h> #include <linux/of.h> +#include <linux/nvmem-provider.h> #include <mtd/mtd-abi.h> @@ -341,6 +342,7 @@ struct mtd_info { struct device dev; int usecount; struct mtd_debug_info dbg; + struct nvmem_device *nvmem; }; int mtd_ooblayout_ecc(struct mtd_info *mtd, int section,