diff options
Diffstat (limited to 'drivers/mtd/spi/ramtron.c')
| -rw-r--r-- | drivers/mtd/spi/ramtron.c | 319 |
1 files changed, 319 insertions, 0 deletions
diff --git a/drivers/mtd/spi/ramtron.c b/drivers/mtd/spi/ramtron.c new file mode 100644 index 0000000000..171390d5c3 --- /dev/null +++ b/drivers/mtd/spi/ramtron.c @@ -0,0 +1,319 @@ +/* + * (C) Copyright 2010 + * Reinhard Meyer, EMK Elektronik, reinhard.meyer@emk-elektronik.de + * + * See file CREDITS for list of people who contributed to this + * project. + * + * 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, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +/* + * Note: RAMTRON SPI FRAMs are ferroelectric, nonvolatile RAMs + * with an interface identical to SPI flash devices. + * However since they behave like RAM there are no delays or + * busy polls required. They can sustain read or write at the + * allowed SPI bus speed, which can be 40 MHz for some devices. + * + * Unfortunately some RAMTRON devices do not have a means of + * identifying them. They will leave the SO line undriven when + * the READ-ID command is issued. It is therefore mandatory + * that the MISO line has a proper pull-up, so that READ-ID + * will return a row of 0xff. This 0xff pseudo-id will cause + * probes by all vendor specific functions that are designed + * to handle it. If the MISO line is not pulled up, READ-ID + * could return any random noise, even mimicking another + * device. + * + * We use CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC + * to define which device will be assumed after a simple status + * register verify. This method is prone to false positive + * detection and should therefore be the last to be tried. + * Enter it in the last position in the table in spi_flash.c! + * + * The define CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC both activates + * compilation of the special handler and defines the device + * to assume. + */ + +#include <common.h> +#include <malloc.h> +#include <spi_flash.h> +#include "spi_flash_internal.h" + +/* RAMTRON commands common to all devices */ +#define CMD_RAMTRON_WREN 0x06 /* Write Enable */ +#define CMD_RAMTRON_WRDI 0x04 /* Write Disable */ +#define CMD_RAMTRON_RDSR 0x05 /* Read Status Register */ +#define CMD_RAMTRON_WRSR 0x01 /* Write Status Register */ +#define CMD_RAMTRON_READ 0x03 /* Read Data Bytes */ +#define CMD_RAMTRON_WRITE 0x02 /* Write Data Bytes */ +/* not all have those: */ +#define CMD_RAMTRON_FSTRD 0x0b /* Fast Read (for compatibility - not used here) */ +#define CMD_RAMTRON_SLEEP 0xb9 /* Enter Sleep Mode */ +#define CMD_RAMTRON_RDID 0x9f /* Read ID */ +#define CMD_RAMTRON_SNR 0xc3 /* Read Serial Number */ + +/* + * Properties of supported FRAMs + * Note: speed is currently not used because we have no method to deliver that + * value to the upper layers + */ +struct ramtron_spi_fram_params { + u32 size; /* size in bytes */ + u8 addr_len; /* number of address bytes */ + u8 merge_cmd; /* some address bits are in the command byte */ + u8 id1; /* device ID 1 (family, density) */ + u8 id2; /* device ID 2 (sub, rev, rsvd) */ + u32 speed; /* max. SPI clock in Hz */ + const char *name; /* name for display and/or matching */ +}; + +struct ramtron_spi_fram { + struct spi_flash flash; + const struct ramtron_spi_fram_params *params; +}; + +static inline struct ramtron_spi_fram *to_ramtron_spi_fram(struct spi_flash + *flash) +{ + return container_of(flash, struct ramtron_spi_fram, flash); +} + +/* + * table describing supported FRAM chips: + * chips without RDID command must have the values 0xff for id1 and id2 + */ +static const struct ramtron_spi_fram_params ramtron_spi_fram_table[] = { + { + .size = 32*1024, + .addr_len = 2, + .merge_cmd = 0, + .id1 = 0x22, + .id2 = 0x00, + .speed = 40000000, + .name = "FM25V02", + }, + { + .size = 32*1024, + .addr_len = 2, + .merge_cmd = 0, + .id1 = 0x22, + .id2 = 0x01, + .speed = 40000000, + .name = "FM25VN02", + }, + { + .size = 64*1024, + .addr_len = 2, + .merge_cmd = 0, + .id1 = 0x23, + .id2 = 0x00, + .speed = 40000000, + .name = "FM25V05", + }, + { + .size = 64*1024, + .addr_len = 2, + .merge_cmd = 0, + .id1 = 0x23, + .id2 = 0x01, + .speed = 40000000, + .name = "FM25VN05", + }, + { + .size = 128*1024, + .addr_len = 3, + .merge_cmd = 0, + .id1 = 0x24, + .id2 = 0x00, + .speed = 40000000, + .name = "FM25V10", + }, + { + .size = 128*1024, + .addr_len = 3, + .merge_cmd = 0, + .id1 = 0x24, + .id2 = 0x01, + .speed = 40000000, + .name = "FM25VN10", + }, +#ifdef CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC + { + .size = 256*1024, + .addr_len = 3, + .merge_cmd = 0, + .id1 = 0xff, + .id2 = 0xff, + .speed = 40000000, + .name = "FM25H20", + }, +#endif +}; + +static int ramtron_common(struct spi_flash *flash, + u32 offset, size_t len, void *buf, u8 command) +{ + struct ramtron_spi_fram *sn = to_ramtron_spi_fram(flash); + u8 cmd[4]; + int cmd_len; + int ret; + + if (sn->params->addr_len == 3 && sn->params->merge_cmd == 0) { + cmd[0] = command; + cmd[1] = offset >> 16; + cmd[2] = offset >> 8; + cmd[3] = offset; + cmd_len = 4; + } else if (sn->params->addr_len == 2 && sn->params->merge_cmd == 0) { + cmd[0] = command; + cmd[1] = offset >> 8; + cmd[2] = offset; + cmd_len = 3; + } else { + printf("SF: unsupported addr_len or merge_cmd\n"); + return -1; + } + + /* claim the bus */ + ret = spi_claim_bus(flash->spi); + if (ret) { + debug("SF: Unable to claim SPI bus\n"); + return ret; + } + + if (command == CMD_RAMTRON_WRITE) { + /* send WREN */ + ret = spi_flash_cmd(flash->spi, CMD_RAMTRON_WREN, NULL, 0); + if (ret < 0) { + debug("SF: Enabling Write failed\n"); + goto releasebus; + } + } + + /* do the transaction */ + if (command == CMD_RAMTRON_WRITE) + ret = spi_flash_cmd_write(flash->spi, cmd, cmd_len, buf, len); + else + ret = spi_flash_cmd_read(flash->spi, cmd, cmd_len, buf, len); + if (ret < 0) + debug("SF: Transaction failed\n"); + +releasebus: + /* release the bus */ + spi_release_bus(flash->spi); + return ret; +} + +static int ramtron_read(struct spi_flash *flash, + u32 offset, size_t len, void *buf) +{ + return ramtron_common(flash, offset, len, buf, + CMD_RAMTRON_READ); +} + +static int ramtron_write(struct spi_flash *flash, + u32 offset, size_t len, const void *buf) +{ + return ramtron_common(flash, offset, len, (void *)buf, + CMD_RAMTRON_WRITE); +} + +int ramtron_erase(struct spi_flash *flash, u32 offset, size_t len) +{ + debug("SF: Erase of RAMTRON FRAMs is pointless\n"); + return -1; +} + +/* + * nore: we are called here with idcode pointing to the first non-0x7f byte + * already! + */ +struct spi_flash *spi_fram_probe_ramtron(struct spi_slave *spi, u8 *idcode) +{ + const struct ramtron_spi_fram_params *params; + struct ramtron_spi_fram *sn; + unsigned int i; +#ifdef CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC + int ret; + u8 sr; +#endif + + /* NOTE: the bus has been claimed before this function is called! */ + switch (idcode[0]) { + case 0xc2: + /* JEDEC conformant RAMTRON id */ + for (i = 0; i < ARRAY_SIZE(ramtron_spi_fram_table); i++) { + params = &ramtron_spi_fram_table[i]; + if (idcode[1] == params->id1 && idcode[2] == params->id2) + goto found; + } + break; +#ifdef CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC + case 0xff: + /* + * probably open MISO line, pulled up. + * We COULD have a non JEDEC conformant FRAM here, + * read the status register to verify + */ + ret = spi_flash_cmd(spi, CMD_RAMTRON_RDSR, &sr, 1); + if (ret) + return NULL; + + /* Bits 5,4,0 are fixed 0 for all devices */ + if ((sr & 0x31) != 0x00) + return NULL; + /* now find the device */ + for (i = 0; i < ARRAY_SIZE(ramtron_spi_fram_table); i++) { + params = &ramtron_spi_fram_table[i]; + if (!strcmp(params->name, CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC)) + goto found; + } + debug("SF: Unsupported non-JEDEC RAMTRON device " + CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC "\n"); + break; +#endif + default: + break; + } + + /* arriving here means no method has found a device we can handle */ + debug("SF/ramtron: unsupported device id0=%02x id1=%02x id2=%02x\n", + idcode[0], idcode[1], idcode[2]); + return NULL; + +found: + sn = malloc(sizeof(*sn)); + if (!sn) { + debug("SF: Failed to allocate memory\n"); + return NULL; + } + + sn->params = params; + sn->flash.spi = spi; + sn->flash.name = params->name; + + sn->flash.write = ramtron_write; + sn->flash.read = ramtron_read; + sn->flash.erase = ramtron_erase; + sn->flash.size = params->size; + + printf("SF: Detected %s with size ", params->name); + print_size(sn->flash.size, "\n"); + + return &sn->flash; +} |