diff options
| -rw-r--r-- | drivers/nvmem/core.c | 153 | ||||
| -rw-r--r-- | include/linux/nvmem-provider.h | 17 |
2 files changed, 166 insertions, 4 deletions
diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index a09ff8409f60..177f5bf27c6d 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -34,6 +34,8 @@ struct nvmem_device { struct bin_attribute eeprom; struct device *base_dev; struct list_head cells; + const struct nvmem_keepout *keepout; + unsigned int nkeepout; nvmem_reg_read_t reg_read; nvmem_reg_write_t reg_write; struct gpio_desc *wp_gpio; @@ -66,8 +68,8 @@ static LIST_HEAD(nvmem_lookup_list); static BLOCKING_NOTIFIER_HEAD(nvmem_notifier); -static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset, - void *val, size_t bytes) +static int __nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset, + void *val, size_t bytes) { if (nvmem->reg_read) return nvmem->reg_read(nvmem->priv, offset, val, bytes); @@ -75,8 +77,8 @@ static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset, return -EINVAL; } -static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset, - void *val, size_t bytes) +static int __nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset, + void *val, size_t bytes) { int ret; @@ -90,6 +92,88 @@ static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset, return -EINVAL; } +static int nvmem_access_with_keepouts(struct nvmem_device *nvmem, + unsigned int offset, void *val, + size_t bytes, int write) +{ + + unsigned int end = offset + bytes; + unsigned int kend, ksize; + const struct nvmem_keepout *keepout = nvmem->keepout; + const struct nvmem_keepout *keepoutend = keepout + nvmem->nkeepout; + int rc; + + /* + * Skip all keepouts before the range being accessed. + * Keepouts are sorted. + */ + while ((keepout < keepoutend) && (keepout->end <= offset)) + keepout++; + + while ((offset < end) && (keepout < keepoutend)) { + /* Access the valid portion before the keepout. */ + if (offset < keepout->start) { + kend = min(end, keepout->start); + ksize = kend - offset; + if (write) + rc = __nvmem_reg_write(nvmem, offset, val, ksize); + else + rc = __nvmem_reg_read(nvmem, offset, val, ksize); + + if (rc) + return rc; + + offset += ksize; + val += ksize; + } + + /* + * Now we're aligned to the start of this keepout zone. Go + * through it. + */ + kend = min(end, keepout->end); + ksize = kend - offset; + if (!write) + memset(val, keepout->value, ksize); + + val += ksize; + offset += ksize; + keepout++; + } + + /* + * If we ran out of keepouts but there's still stuff to do, send it + * down directly + */ + if (offset < end) { + ksize = end - offset; + if (write) + return __nvmem_reg_write(nvmem, offset, val, ksize); + else + return __nvmem_reg_read(nvmem, offset, val, ksize); + } + + return 0; +} + +static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset, + void *val, size_t bytes) +{ + if (!nvmem->nkeepout) + return __nvmem_reg_read(nvmem, offset, val, bytes); + + return nvmem_access_with_keepouts(nvmem, offset, val, bytes, false); +} + +static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset, + void *val, size_t bytes) +{ + if (!nvmem->nkeepout) + return __nvmem_reg_write(nvmem, offset, val, bytes); + + return nvmem_access_with_keepouts(nvmem, offset, val, bytes, true); +} + #ifdef CONFIG_NVMEM_SYSFS static const char * const nvmem_type_str[] = { [NVMEM_TYPE_UNKNOWN] = "Unknown", @@ -533,6 +617,59 @@ nvmem_find_cell_by_name(struct nvmem_device *nvmem, const char *cell_id) return cell; } +static int nvmem_validate_keepouts(struct nvmem_device *nvmem) +{ + unsigned int cur = 0; + const struct nvmem_keepout *keepout = nvmem->keepout; + const struct nvmem_keepout *keepoutend = keepout + nvmem->nkeepout; + + while (keepout < keepoutend) { + /* Ensure keepouts are sorted and don't overlap. */ + if (keepout->start < cur) { + dev_err(&nvmem->dev, + "Keepout regions aren't sorted or overlap.\n"); + + return -ERANGE; + } + + if (keepout->end < keepout->start) { + dev_err(&nvmem->dev, + "Invalid keepout region.\n"); + + return -EINVAL; + } + + /* + * Validate keepouts (and holes between) don't violate + * word_size constraints. + */ + if ((keepout->end - keepout->start < nvmem->word_size) || + ((keepout->start != cur) && + (keepout->start - cur < nvmem->word_size))) { + + dev_err(&nvmem->dev, + "Keepout regions violate word_size constraints.\n"); + + return -ERANGE; + } + + /* Validate keepouts don't violate stride (alignment). */ + if (!IS_ALIGNED(keepout->start, nvmem->stride) || + !IS_ALIGNED(keepout->end, nvmem->stride)) { + + dev_err(&nvmem->dev, + "Keepout regions violate stride.\n"); + + return -EINVAL; + } + + cur = keepout->end; + keepout++; + } + + return 0; +} + static int nvmem_add_cells_from_of(struct nvmem_device *nvmem) { struct device_node *parent, *child; @@ -647,6 +784,8 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) nvmem->type = config->type; nvmem->reg_read = config->reg_read; nvmem->reg_write = config->reg_write; + nvmem->keepout = config->keepout; + nvmem->nkeepout = config->nkeepout; if (!config->no_of_node) nvmem->dev.of_node = config->dev->of_node; @@ -671,6 +810,12 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) nvmem->dev.groups = nvmem_dev_groups; #endif + if (nvmem->nkeepout) { + rval = nvmem_validate_keepouts(nvmem); + if (rval) + goto err_put_device; + } + dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name); rval = device_register(&nvmem->dev); diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h index 06409a6c40bc..e162b757b6d5 100644 --- a/include/linux/nvmem-provider.h +++ b/include/linux/nvmem-provider.h @@ -31,6 +31,19 @@ enum nvmem_type { #define NVMEM_DEVID_AUTO (-2) /** + * struct nvmem_keepout - NVMEM register keepout range. + * + * @start: The first byte offset to avoid. + * @end: One beyond the last byte offset to avoid. + * @value: The byte to fill reads with for this region. + */ +struct nvmem_keepout { + unsigned int start; + unsigned int end; + unsigned char value; +}; + +/** * struct nvmem_config - NVMEM device configuration * * @dev: Parent device. @@ -39,6 +52,8 @@ enum nvmem_type { * @owner: Pointer to exporter module. Used for refcounting. * @cells: Optional array of pre-defined NVMEM cells. * @ncells: Number of elements in cells. + * @keepout: Optional array of keepout ranges (sorted ascending by start). + * @nkeepout: Number of elements in the keepout array. * @type: Type of the nvmem storage * @read_only: Device is read-only. * @root_only: Device is accessibly to root only. @@ -66,6 +81,8 @@ struct nvmem_config { struct gpio_desc *wp_gpio; const struct nvmem_cell_info *cells; int ncells; + const struct nvmem_keepout *keepout; + unsigned int nkeepout; enum nvmem_type type; bool read_only; bool root_only; |