diff options
| -rw-r--r-- | drivers/nvmem/Kconfig | 6 | ||||
| -rw-r--r-- | drivers/nvmem/Makefile | 3 | ||||
| -rw-r--r-- | drivers/nvmem/rave-sp-eeprom.c | 357 |
3 files changed, 366 insertions, 0 deletions
diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig index 1090924efdb1..54a3c298247b 100644 --- a/drivers/nvmem/Kconfig +++ b/drivers/nvmem/Kconfig @@ -175,4 +175,10 @@ config NVMEM_SNVS_LPGPR This driver can also be built as a module. If so, the module will be called nvmem-snvs-lpgpr. +config RAVE_SP_EEPROM + tristate "Rave SP EEPROM Support" + depends on RAVE_SP_CORE + help + Say y here to enable Rave SP EEPROM support. + endif diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile index e54dcfa6565a..27e96a8efd1c 100644 --- a/drivers/nvmem/Makefile +++ b/drivers/nvmem/Makefile @@ -37,3 +37,6 @@ obj-$(CONFIG_MESON_MX_EFUSE) += nvmem_meson_mx_efuse.o nvmem_meson_mx_efuse-y := meson-mx-efuse.o obj-$(CONFIG_NVMEM_SNVS_LPGPR) += nvmem_snvs_lpgpr.o nvmem_snvs_lpgpr-y := snvs_lpgpr.o +obj-$(CONFIG_RAVE_SP_EEPROM) += nvmem-rave-sp-eeprom.o +nvmem-rave-sp-eeprom-y := rave-sp-eeprom.o + diff --git a/drivers/nvmem/rave-sp-eeprom.c b/drivers/nvmem/rave-sp-eeprom.c new file mode 100644 index 000000000000..50aeea6ec6cc --- /dev/null +++ b/drivers/nvmem/rave-sp-eeprom.c @@ -0,0 +1,357 @@ +// SPDX-License-Identifier: GPL-2.0+ + +/* + * EEPROM driver for RAVE SP + * + * Copyright (C) 2018 Zodiac Inflight Innovations + * + */ +#include <linux/kernel.h> +#include <linux/mfd/rave-sp.h> +#include <linux/module.h> +#include <linux/nvmem-provider.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/sizes.h> + +/** + * enum rave_sp_eeprom_access_type - Supported types of EEPROM access + * + * @RAVE_SP_EEPROM_WRITE: EEPROM write + * @RAVE_SP_EEPROM_READ: EEPROM read + */ +enum rave_sp_eeprom_access_type { + RAVE_SP_EEPROM_WRITE = 0, + RAVE_SP_EEPROM_READ = 1, +}; + +/** + * enum rave_sp_eeprom_header_size - EEPROM command header sizes + * + * @RAVE_SP_EEPROM_HEADER_SMALL: EEPROM header size for "small" devices (< 8K) + * @RAVE_SP_EEPROM_HEADER_BIG: EEPROM header size for "big" devices (> 8K) + */ +enum rave_sp_eeprom_header_size { + RAVE_SP_EEPROM_HEADER_SMALL = 4U, + RAVE_SP_EEPROM_HEADER_BIG = 5U, +}; + +#define RAVE_SP_EEPROM_PAGE_SIZE 32U + +/** + * struct rave_sp_eeprom_page - RAVE SP EEPROM page + * + * @type: Access type (see enum rave_sp_eeprom_access_type) + * @success: Success flag (Success = 1, Failure = 0) + * @data: Read data + + * Note this structure corresponds to RSP_*_EEPROM payload from RAVE + * SP ICD + */ +struct rave_sp_eeprom_page { + u8 type; + u8 success; + u8 data[RAVE_SP_EEPROM_PAGE_SIZE]; +} __packed; + +/** + * struct rave_sp_eeprom - RAVE SP EEPROM device + * + * @sp: Pointer to parent RAVE SP device + * @mutex: Lock protecting access to EEPROM + * @address: EEPROM device address + * @header_size: Size of EEPROM command header for this device + * @dev: Pointer to corresponding struct device used for logging + */ +struct rave_sp_eeprom { + struct rave_sp *sp; + struct mutex mutex; + u8 address; + unsigned int header_size; + struct device *dev; +}; + +/** + * rave_sp_eeprom_io - Low-level part of EEPROM page access + * + * @eeprom: EEPROM device to write to + * @type: EEPROM access type (read or write) + * @idx: number of the EEPROM page + * @page: Data to write or buffer to store result (via page->data) + * + * This function does all of the low-level work required to perform a + * EEPROM access. This includes formatting correct command payload, + * sending it and checking received results. + * + * Returns zero in case of success or negative error code in + * case of failure. + */ +static int rave_sp_eeprom_io(struct rave_sp_eeprom *eeprom, + enum rave_sp_eeprom_access_type type, + u16 idx, + struct rave_sp_eeprom_page *page) +{ + const bool is_write = type == RAVE_SP_EEPROM_WRITE; + const unsigned int data_size = is_write ? sizeof(page->data) : 0; + const unsigned int cmd_size = eeprom->header_size + data_size; + const unsigned int rsp_size = + is_write ? sizeof(*page) - sizeof(page->data) : sizeof(*page); + unsigned int offset = 0; + u8 cmd[cmd_size]; + int ret; + + cmd[offset++] = eeprom->address; + cmd[offset++] = 0; + cmd[offset++] = type; + cmd[offset++] = idx; + + /* + * If there's still room in this command's header it means we + * are talkin to EEPROM that uses 16-bit page numbers and we + * have to specify index's MSB in payload as well. + */ + if (offset < eeprom->header_size) + cmd[offset++] = idx >> 8; + /* + * Copy our data to write to command buffer first. In case of + * a read data_size should be zero and memcpy would become a + * no-op + */ + memcpy(&cmd[offset], page->data, data_size); + + ret = rave_sp_exec(eeprom->sp, cmd, cmd_size, page, rsp_size); + if (ret) + return ret; + + if (page->type != type) + return -EPROTO; + + if (!page->success) + return -EIO; + + return 0; +} + +/** + * rave_sp_eeprom_page_access - Access single EEPROM page + * + * @eeprom: EEPROM device to access + * @type: Access type to perform (read or write) + * @offset: Offset within EEPROM to access + * @data: Data buffer + * @data_len: Size of the data buffer + * + * This function performs a generic access to a single page or a + * portion thereof. Requested access MUST NOT cross the EEPROM page + * boundary. + * + * Returns zero in case of success or negative error code in + * case of failure. + */ +static int +rave_sp_eeprom_page_access(struct rave_sp_eeprom *eeprom, + enum rave_sp_eeprom_access_type type, + unsigned int offset, u8 *data, + size_t data_len) +{ + const unsigned int page_offset = offset % RAVE_SP_EEPROM_PAGE_SIZE; + const unsigned int page_nr = offset / RAVE_SP_EEPROM_PAGE_SIZE; + struct rave_sp_eeprom_page page; + int ret; + + /* + * This function will not work if data access we've been asked + * to do is crossing EEPROM page boundary. Normally this + * should never happen and getting here would indicate a bug + * in the code. + */ + if (WARN_ON(data_len > sizeof(page.data) - page_offset)) + return -EINVAL; + + if (type == RAVE_SP_EEPROM_WRITE) { + /* + * If doing a partial write we need to do a read first + * to fill the rest of the page with correct data. + */ + if (data_len < RAVE_SP_EEPROM_PAGE_SIZE) { + ret = rave_sp_eeprom_io(eeprom, RAVE_SP_EEPROM_READ, + page_nr, &page); + if (ret) + return ret; + } + + memcpy(&page.data[page_offset], data, data_len); + } + + ret = rave_sp_eeprom_io(eeprom, type, page_nr, &page); + if (ret) + return ret; + + /* + * Since we receive the result of the read via 'page.data' + * buffer we need to copy that to 'data' + */ + if (type == RAVE_SP_EEPROM_READ) + memcpy(data, &page.data[page_offset], data_len); + + return 0; +} + +/** + * rave_sp_eeprom_access - Access EEPROM data + * + * @eeprom: EEPROM device to access + * @type: Access type to perform (read or write) + * @offset: Offset within EEPROM to access + * @data: Data buffer + * @data_len: Size of the data buffer + * + * This function performs a generic access (either read or write) at + * arbitrary offset (not necessary page aligned) of arbitrary length + * (is not constrained by EEPROM page size). + * + * Returns zero in case of success or negative error code in case of + * failure. + */ +static int rave_sp_eeprom_access(struct rave_sp_eeprom *eeprom, + enum rave_sp_eeprom_access_type type, + unsigned int offset, u8 *data, + unsigned int data_len) +{ + unsigned int residue; + unsigned int chunk; + unsigned int head; + int ret; + + mutex_lock(&eeprom->mutex); + + head = offset % RAVE_SP_EEPROM_PAGE_SIZE; + residue = data_len; + + do { + /* + * First iteration, if we are doing an access that is + * not 32-byte aligned, we need to access only data up + * to a page boundary to avoid corssing it in + * rave_sp_eeprom_page_access() + */ + if (unlikely(head)) { + chunk = RAVE_SP_EEPROM_PAGE_SIZE - head; + /* + * This can only happen once per + * rave_sp_eeprom_access() call, so we set + * head to zero to process all the other + * iterations normally. + */ + head = 0; + } else { + chunk = RAVE_SP_EEPROM_PAGE_SIZE; + } + + /* + * We should never read more that 'residue' bytes + */ + chunk = min(chunk, residue); + ret = rave_sp_eeprom_page_access(eeprom, type, offset, + data, chunk); + if (ret) + goto out; + + residue -= chunk; + offset += chunk; + data += chunk; + } while (residue); +out: + mutex_unlock(&eeprom->mutex); + return ret; +} + +static int rave_sp_eeprom_reg_read(void *eeprom, unsigned int offset, + void *val, size_t bytes) +{ + return rave_sp_eeprom_access(eeprom, RAVE_SP_EEPROM_READ, + offset, val, bytes); +} + +static int rave_sp_eeprom_reg_write(void *eeprom, unsigned int offset, + void *val, size_t bytes) +{ + return rave_sp_eeprom_access(eeprom, RAVE_SP_EEPROM_WRITE, + offset, val, bytes); +} + +static int rave_sp_eeprom_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct rave_sp *sp = dev_get_drvdata(dev->parent); + struct device_node *np = dev->of_node; + struct nvmem_config config = { 0 }; + struct rave_sp_eeprom *eeprom; + struct nvmem_device *nvmem; + u32 reg[2], size; + + if (of_property_read_u32_array(np, "reg", reg, ARRAY_SIZE(reg))) { + dev_err(dev, "Failed to parse \"reg\" property\n"); + return -EINVAL; + } + + size = reg[1]; + /* + * Per ICD, we have no more than 2 bytes to specify EEPROM + * page. + */ + if (size > U16_MAX * RAVE_SP_EEPROM_PAGE_SIZE) { + dev_err(dev, "Specified size is too big\n"); + return -EINVAL; + } + + eeprom = devm_kzalloc(dev, sizeof(*eeprom), GFP_KERNEL); + if (!eeprom) + return -ENOMEM; + + eeprom->address = reg[0]; + eeprom->sp = sp; + eeprom->dev = dev; + + if (size > SZ_8K) + eeprom->header_size = RAVE_SP_EEPROM_HEADER_BIG; + else + eeprom->header_size = RAVE_SP_EEPROM_HEADER_SMALL; + + mutex_init(&eeprom->mutex); + + config.id = -1; + of_property_read_string(np, "zii,eeprom-name", &config.name); + config.priv = eeprom; + config.dev = dev; + config.size = size; + config.reg_read = rave_sp_eeprom_reg_read; + config.reg_write = rave_sp_eeprom_reg_write; + config.word_size = 1; + config.stride = 1; + + nvmem = devm_nvmem_register(dev, &config); + + return PTR_ERR_OR_ZERO(nvmem); +} + +static const struct of_device_id rave_sp_eeprom_of_match[] = { + { .compatible = "zii,rave-sp-eeprom" }, + {} +}; +MODULE_DEVICE_TABLE(of, rave_sp_eeprom_of_match); + +static struct platform_driver rave_sp_eeprom_driver = { + .probe = rave_sp_eeprom_probe, + .driver = { + .name = KBUILD_MODNAME, + .of_match_table = rave_sp_eeprom_of_match, + }, +}; +module_platform_driver(rave_sp_eeprom_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>"); +MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>"); +MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>"); +MODULE_DESCRIPTION("RAVE SP EEPROM driver"); |