From: Michael Walle <michael@walle.cc> To: linux-mtd@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Miquel Raynal <miquel.raynal@bootlin.com>, Richard Weinberger <richard@nod.at>, Vignesh Raghavendra <vigneshr@ti.com>, Rob Herring <robh+dt@kernel.org>, Srinivas Kandagatla <srinivas.kandagatla@linaro.org>, Michael Walle <michael@walle.cc> Subject: [PATCH 5/5] mtd: core: add OTP nvmem provider support Date: Fri, 16 Apr 2021 13:49:28 +0200 [thread overview] Message-ID: <20210416114928.27758-6-michael@walle.cc> (raw) In-Reply-To: <20210416114928.27758-1-michael@walle.cc> Flash OTP regions can already be read via user space. Some boards have their serial number or MAC addresses stored in the OTP regions. Add support for them being a (read-only) nvmem provider. The API to read the OTP data is already in place. It distinguishes between factory and user OTP, thus there are up to two different providers. Signed-off-by: Michael Walle <michael@walle.cc> --- Changes since RFC: - none drivers/mtd/mtdcore.c | 149 ++++++++++++++++++++++++++++++++++++++++ include/linux/mtd/mtd.h | 2 + 2 files changed, 151 insertions(+) diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index 0bc6871c3863..92201e3d187a 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -777,6 +777,147 @@ static void mtd_set_dev_defaults(struct mtd_info *mtd) mutex_init(&mtd->master.chrdev_lock); } +static ssize_t mtd_otp_size(struct mtd_info *mtd, bool is_user) +{ + struct otp_info *info = kmalloc(PAGE_SIZE, GFP_KERNEL); + ssize_t size = 0; + unsigned int i; + size_t retlen; + int ret; + + if (is_user) + ret = mtd_get_user_prot_info(mtd, PAGE_SIZE, &retlen, info); + else + ret = mtd_get_fact_prot_info(mtd, PAGE_SIZE, &retlen, info); + if (ret) + goto err; + + for (i = 0; i < retlen / sizeof(*info); i++) { + size += info->length; + info++; + } + + kfree(info); + return size; + +err: + kfree(info); + return ret; +} + +static struct nvmem_device *mtd_otp_nvmem_register(struct mtd_info *mtd, + const char *name, int size, + nvmem_reg_read_t reg_read, + const char *compatible) +{ + struct nvmem_device *nvmem = NULL; + struct nvmem_config config = {}; + struct device_node *np; + + /* DT binding is optional */ + np = of_get_compatible_child(mtd->dev.of_node, compatible); + + /* OTP nvmem will be registered on the physical device */ + config.dev = mtd->dev.parent; + config.name = name; + config.id = NVMEM_DEVID_NONE; + config.owner = THIS_MODULE; + config.type = NVMEM_TYPE_OTP; + config.root_only = true; + config.reg_read = reg_read; + config.size = size; + config.of_node = np; + config.priv = mtd; + + nvmem = nvmem_register(&config); + /* Just ignore if there is no NVMEM support in the kernel */ + if (IS_ERR(nvmem) && PTR_ERR(nvmem) == -EOPNOTSUPP) + nvmem = NULL; + + of_node_put(np); + + return nvmem; +} + +static int mtd_nvmem_user_otp_reg_read(void *priv, unsigned int offset, + void *val, size_t bytes) +{ + struct mtd_info *mtd = priv; + size_t retlen; + int ret; + + ret = mtd_read_user_prot_reg(mtd, offset, bytes, &retlen, val); + if (ret) + return ret; + + return retlen == bytes ? 0 : -EIO; +} + +static int mtd_nvmem_fact_otp_reg_read(void *priv, unsigned int offset, + void *val, size_t bytes) +{ + struct mtd_info *mtd = priv; + size_t retlen; + int ret; + + ret = mtd_read_fact_prot_reg(mtd, offset, bytes, &retlen, val); + if (ret) + return ret; + + return retlen == bytes ? 0 : -EIO; +} + +static int mtd_otp_nvmem_add(struct mtd_info *mtd) +{ + struct nvmem_device *nvmem; + ssize_t size; + int err; + + if (mtd->_get_user_prot_info && mtd->_read_user_prot_reg) { + size = mtd_otp_size(mtd, true); + if (size < 0) + return size; + + if (size > 0) { + nvmem = mtd_otp_nvmem_register(mtd, "user-otp", size, + mtd_nvmem_user_otp_reg_read, + "mtd-user-otp"); + if (IS_ERR(nvmem)) { + dev_err(&mtd->dev, "Failed to register OTP NVMEM device\n"); + return PTR_ERR(nvmem); + } + mtd->otp_user_nvmem = nvmem; + } + } + + if (mtd->_get_fact_prot_info && mtd->_read_fact_prot_reg) { + size = mtd_otp_size(mtd, false); + if (size < 0) { + err = size; + goto err; + } + + if (size > 0) { + nvmem = mtd_otp_nvmem_register(mtd, "factory-otp", size, + mtd_nvmem_fact_otp_reg_read, + "mtd-factory-otp"); + if (IS_ERR(nvmem)) { + dev_err(&mtd->dev, "Failed to register OTP NVMEM device\n"); + err = PTR_ERR(nvmem); + goto err; + } + mtd->otp_factory_nvmem = nvmem; + } + } + + return 0; + +err: + if (mtd->otp_user_nvmem) + nvmem_unregister(mtd->otp_user_nvmem); + return err; +} + /** * mtd_device_parse_register - parse partitions and register an MTD device. * @@ -852,6 +993,8 @@ int mtd_device_parse_register(struct mtd_info *mtd, const char * const *types, register_reboot_notifier(&mtd->reboot_notifier); } + ret = mtd_otp_nvmem_add(mtd); + out: if (ret && device_is_registered(&mtd->dev)) del_mtd_device(mtd); @@ -873,6 +1016,12 @@ int mtd_device_unregister(struct mtd_info *master) if (master->_reboot) unregister_reboot_notifier(&master->reboot_notifier); + if (master->otp_user_nvmem) + nvmem_unregister(master->otp_user_nvmem); + + if (master->otp_factory_nvmem) + nvmem_unregister(master->otp_factory_nvmem); + err = del_mtd_partitions(master); if (err) return err; diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h index 4aac200ca8b5..71e751d18c22 100644 --- a/include/linux/mtd/mtd.h +++ b/include/linux/mtd/mtd.h @@ -379,6 +379,8 @@ struct mtd_info { int usecount; struct mtd_debug_info dbg; struct nvmem_device *nvmem; + struct nvmem_device *otp_user_nvmem; + struct nvmem_device *otp_factory_nvmem; /* * Parent device from the MTD partition point of view. -- 2.20.1
WARNING: multiple messages have this Message-ID (diff)
From: Michael Walle <michael@walle.cc> To: linux-mtd@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Miquel Raynal <miquel.raynal@bootlin.com>, Richard Weinberger <richard@nod.at>, Vignesh Raghavendra <vigneshr@ti.com>, Rob Herring <robh+dt@kernel.org>, Srinivas Kandagatla <srinivas.kandagatla@linaro.org>, Michael Walle <michael@walle.cc> Subject: [PATCH 5/5] mtd: core: add OTP nvmem provider support Date: Fri, 16 Apr 2021 13:49:28 +0200 [thread overview] Message-ID: <20210416114928.27758-6-michael@walle.cc> (raw) In-Reply-To: <20210416114928.27758-1-michael@walle.cc> Flash OTP regions can already be read via user space. Some boards have their serial number or MAC addresses stored in the OTP regions. Add support for them being a (read-only) nvmem provider. The API to read the OTP data is already in place. It distinguishes between factory and user OTP, thus there are up to two different providers. Signed-off-by: Michael Walle <michael@walle.cc> --- Changes since RFC: - none drivers/mtd/mtdcore.c | 149 ++++++++++++++++++++++++++++++++++++++++ include/linux/mtd/mtd.h | 2 + 2 files changed, 151 insertions(+) diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index 0bc6871c3863..92201e3d187a 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -777,6 +777,147 @@ static void mtd_set_dev_defaults(struct mtd_info *mtd) mutex_init(&mtd->master.chrdev_lock); } +static ssize_t mtd_otp_size(struct mtd_info *mtd, bool is_user) +{ + struct otp_info *info = kmalloc(PAGE_SIZE, GFP_KERNEL); + ssize_t size = 0; + unsigned int i; + size_t retlen; + int ret; + + if (is_user) + ret = mtd_get_user_prot_info(mtd, PAGE_SIZE, &retlen, info); + else + ret = mtd_get_fact_prot_info(mtd, PAGE_SIZE, &retlen, info); + if (ret) + goto err; + + for (i = 0; i < retlen / sizeof(*info); i++) { + size += info->length; + info++; + } + + kfree(info); + return size; + +err: + kfree(info); + return ret; +} + +static struct nvmem_device *mtd_otp_nvmem_register(struct mtd_info *mtd, + const char *name, int size, + nvmem_reg_read_t reg_read, + const char *compatible) +{ + struct nvmem_device *nvmem = NULL; + struct nvmem_config config = {}; + struct device_node *np; + + /* DT binding is optional */ + np = of_get_compatible_child(mtd->dev.of_node, compatible); + + /* OTP nvmem will be registered on the physical device */ + config.dev = mtd->dev.parent; + config.name = name; + config.id = NVMEM_DEVID_NONE; + config.owner = THIS_MODULE; + config.type = NVMEM_TYPE_OTP; + config.root_only = true; + config.reg_read = reg_read; + config.size = size; + config.of_node = np; + config.priv = mtd; + + nvmem = nvmem_register(&config); + /* Just ignore if there is no NVMEM support in the kernel */ + if (IS_ERR(nvmem) && PTR_ERR(nvmem) == -EOPNOTSUPP) + nvmem = NULL; + + of_node_put(np); + + return nvmem; +} + +static int mtd_nvmem_user_otp_reg_read(void *priv, unsigned int offset, + void *val, size_t bytes) +{ + struct mtd_info *mtd = priv; + size_t retlen; + int ret; + + ret = mtd_read_user_prot_reg(mtd, offset, bytes, &retlen, val); + if (ret) + return ret; + + return retlen == bytes ? 0 : -EIO; +} + +static int mtd_nvmem_fact_otp_reg_read(void *priv, unsigned int offset, + void *val, size_t bytes) +{ + struct mtd_info *mtd = priv; + size_t retlen; + int ret; + + ret = mtd_read_fact_prot_reg(mtd, offset, bytes, &retlen, val); + if (ret) + return ret; + + return retlen == bytes ? 0 : -EIO; +} + +static int mtd_otp_nvmem_add(struct mtd_info *mtd) +{ + struct nvmem_device *nvmem; + ssize_t size; + int err; + + if (mtd->_get_user_prot_info && mtd->_read_user_prot_reg) { + size = mtd_otp_size(mtd, true); + if (size < 0) + return size; + + if (size > 0) { + nvmem = mtd_otp_nvmem_register(mtd, "user-otp", size, + mtd_nvmem_user_otp_reg_read, + "mtd-user-otp"); + if (IS_ERR(nvmem)) { + dev_err(&mtd->dev, "Failed to register OTP NVMEM device\n"); + return PTR_ERR(nvmem); + } + mtd->otp_user_nvmem = nvmem; + } + } + + if (mtd->_get_fact_prot_info && mtd->_read_fact_prot_reg) { + size = mtd_otp_size(mtd, false); + if (size < 0) { + err = size; + goto err; + } + + if (size > 0) { + nvmem = mtd_otp_nvmem_register(mtd, "factory-otp", size, + mtd_nvmem_fact_otp_reg_read, + "mtd-factory-otp"); + if (IS_ERR(nvmem)) { + dev_err(&mtd->dev, "Failed to register OTP NVMEM device\n"); + err = PTR_ERR(nvmem); + goto err; + } + mtd->otp_factory_nvmem = nvmem; + } + } + + return 0; + +err: + if (mtd->otp_user_nvmem) + nvmem_unregister(mtd->otp_user_nvmem); + return err; +} + /** * mtd_device_parse_register - parse partitions and register an MTD device. * @@ -852,6 +993,8 @@ int mtd_device_parse_register(struct mtd_info *mtd, const char * const *types, register_reboot_notifier(&mtd->reboot_notifier); } + ret = mtd_otp_nvmem_add(mtd); + out: if (ret && device_is_registered(&mtd->dev)) del_mtd_device(mtd); @@ -873,6 +1016,12 @@ int mtd_device_unregister(struct mtd_info *master) if (master->_reboot) unregister_reboot_notifier(&master->reboot_notifier); + if (master->otp_user_nvmem) + nvmem_unregister(master->otp_user_nvmem); + + if (master->otp_factory_nvmem) + nvmem_unregister(master->otp_factory_nvmem); + err = del_mtd_partitions(master); if (err) return err; diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h index 4aac200ca8b5..71e751d18c22 100644 --- a/include/linux/mtd/mtd.h +++ b/include/linux/mtd/mtd.h @@ -379,6 +379,8 @@ struct mtd_info { int usecount; struct mtd_debug_info dbg; struct nvmem_device *nvmem; + struct nvmem_device *otp_user_nvmem; + struct nvmem_device *otp_factory_nvmem; /* * Parent device from the MTD partition point of view. -- 2.20.1 ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/
next prev parent reply other threads:[~2021-04-16 11:49 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-04-16 11:49 [PATCH 0/5] mtd: core: OTP nvmem provider support Michael Walle 2021-04-16 11:49 ` Michael Walle 2021-04-16 11:49 ` [PATCH 1/5] nvmem: core: allow specifying of_node Michael Walle 2021-04-16 11:49 ` Michael Walle 2021-04-16 11:49 ` [PATCH 2/5] dt-bindings: mtd: add YAML schema for the generic MTD bindings Michael Walle 2021-04-16 11:49 ` Michael Walle 2021-04-16 11:49 ` [PATCH 3/5] dt-bindings: mtd: add OTP bindings Michael Walle 2021-04-16 11:49 ` Michael Walle 2021-04-16 18:30 ` Rob Herring 2021-04-16 18:30 ` Rob Herring 2021-04-16 18:46 ` Rob Herring 2021-04-16 18:46 ` Rob Herring 2021-04-16 11:49 ` [PATCH 4/5] dt-bindings: mtd: spi-nor: add otp property Michael Walle 2021-04-16 11:49 ` Michael Walle 2021-04-16 18:30 ` Rob Herring 2021-04-16 18:30 ` Rob Herring 2021-04-16 11:49 ` Michael Walle [this message] 2021-04-16 11:49 ` [PATCH 5/5] mtd: core: add OTP nvmem provider support Michael Walle 2021-04-16 18:44 ` [PATCH 0/5] mtd: core: " Rob Herring 2021-04-16 18:44 ` Rob Herring 2021-04-16 19:26 ` Michael Walle 2021-04-16 19:26 ` Michael Walle 2021-04-20 14:08 ` Rob Herring 2021-04-20 14:08 ` Rob Herring 2021-04-20 15:03 ` Michael Walle 2021-04-20 15:03 ` Michael Walle
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