This is a minimal port of a kernel commit 3b51f47be171 ("nvmem: Add
RAVE SP EEPROM driver"). All of the changes were kept to a minimum and
limited to impedance matching between Barebox/Linux driver API.
Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
---
drivers/nvmem/Kconfig | 7 +
drivers/nvmem/Makefile | 5 +-
drivers/nvmem/rave-sp-eeprom.c | 361 +++++++++++++++++++++++++++++++++
3 files changed, 372 insertions(+), 1 deletion(-)
create mode 100644 drivers/nvmem/rave-sp-eeprom.c
diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index a3797b4aa..38b6f4241 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -36,4 +36,11 @@ config IMX_OCOTP_WRITE
the value of the address by 4.
mw -l -d /dev/imx-ocotp 0x8C 0x00001234
mw -l -d /dev/imx-ocotp 0x88 0x56789ABC
+
+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 998a9c4b9..716e5dbe8 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -10,4 +10,7 @@ obj-$(CONFIG_NVMEM_SNVS_LPGPR) += nvmem_snvs_lpgpr.o
nvmem_snvs_lpgpr-y := snvs_lpgpr.o
obj-$(CONFIG_IMX_OCOTP) += nvmem_ocotp.o
-nvmem_ocotp-y := ocotp.o
\ No newline at end of file
+nvmem_ocotp-y := ocotp.o
+
+obj-$(CONFIG_RAVE_SP_EEPROM) += nvmem-rave-sp-eeprom.o
+nvmem-rave-sp-eeprom-y := rave-sp-eeprom.o
\ No newline at end of file
diff --git a/drivers/nvmem/rave-sp-eeprom.c b/drivers/nvmem/rave-sp-eeprom.c
new file mode 100644
index 000000000..5fd429f16
--- /dev/null
+++ b/drivers/nvmem/rave-sp-eeprom.c
@@ -0,0 +1,361 @@
+/*
+ * EEPROM driver for RAVE SP
+ *
+ * Copyright (C) 2017 Zodiac Inflight Innovations
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <common.h>
+#include <driver.h>
+#include <init.h>
+#include <io.h>
+#include <of.h>
+#include <of_device.h>
+#include <malloc.h>
+#include <linux/sizes.h>
+#include <linux/mfd/rave-sp.h>
+#include <linux/nvmem-provider.h>
+
+/**
+ * enum rave_sp_eeprom_access_type - Supported types of EEPROM access
+ *
+ * @RAVE_SP_EEPROM_WRITE: EEPROM write
+ * @RAVE_SP_EEPROM_READ: EEPROM read
+ *
+ * Note that values of both constant are chose so that they'd match
+ * similar values from RAVE SP ICD.
+ */
+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, < 2M)
+ *
+ * Note that values of both constant are chose so that they'd match
+ * similar values from RAVE SP ICD.
+ */
+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 that the layout of this structure is made to follow the layout
+ * of RSP_*_EEPROM from device's ICD (only the data portion of it due
+ * to how rave_sp_exec() returns data)
+ */
+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 (first byte of the command to access it)
+ * @header_size: Size of EEPROM command header for this device
+ */
+struct rave_sp_eeprom {
+ struct rave_sp *sp;
+ u8 address;
+ unsigned int header_size;
+};
+
+/**
+ * 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-lever work required to perform a
+ * EEPROM access. This includes formatting corredct 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 (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;
+
+ 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 (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)
+ return ret;
+
+ residue -= chunk;
+ offset += chunk;
+ data += chunk;
+ } while (residue);
+
+ return 0;
+}
+
+static int rave_sp_eeprom_read(struct device_d *dev, const int offset,
+ void *val, int bytes)
+{
+ return rave_sp_eeprom_access(dev->parent->priv,
+ RAVE_SP_EEPROM_READ,
+ offset, val, bytes);
+}
+
+static int rave_sp_eeprom_write(struct device_d *dev, const int offset,
+ const void *val, int bytes)
+{
+ return rave_sp_eeprom_access(dev->parent->priv,
+ RAVE_SP_EEPROM_WRITE,
+ offset, (void *)val, bytes);
+}
+
+static const struct nvmem_bus rave_sp_eeprom_nvmem_bus = {
+ .write = rave_sp_eeprom_write,
+ .read = rave_sp_eeprom_read,
+};
+
+static int rave_sp_eeprom_probe(struct device_d *dev)
+{
+ struct rave_sp *sp = dev->parent->priv;
+ struct nvmem_config config = { 0 };
+ struct rave_sp_eeprom *eeprom;
+ struct nvmem_device *nvmem;
+ u32 reg[2], size;
+
+ if (of_property_read_u32_array(dev->device_node,
+ "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 = xzalloc(sizeof(*eeprom));
+ eeprom->address = reg[0];
+ eeprom->sp = sp;
+
+ dev->priv = eeprom;
+
+ if (size > SZ_8K)
+ eeprom->header_size = RAVE_SP_EEPROM_HEADER_BIG;
+ else
+ eeprom->header_size = RAVE_SP_EEPROM_HEADER_SMALL;
+
+ config.name = dev_name(dev);
+ config.dev = dev;
+ config.word_size = 1;
+ config.stride = 1;
+ config.size = reg[1];
+ config.bus = &rave_sp_eeprom_nvmem_bus;
+
+ nvmem = nvmem_register(&config);
+ if (IS_ERR(nvmem)) {
+ free(eeprom);
+ return PTR_ERR(nvmem);
+ }
+
+ return 0;
+}
+
+static __maybe_unused const struct of_device_id rave_sp_eeprom_of_match[] = {
+ { .compatible = "zii,rave-sp-eeprom" },
+ {}
+};
+
+static struct driver_d rave_sp_eeprom_driver = {
+ .name = "rave-sp-eeprom",
+ .probe = rave_sp_eeprom_probe,
+ .of_compatible = DRV_OF_COMPAT(rave_sp_eeprom_of_match),
+};
+console_platform_driver(rave_sp_eeprom_driver);
--
2.17.1
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