Hi Mike,
On Mon, Mar 12, 2012 at 8:22 AM, Mike Frysinger <vap...@gentoo.org> wrote:
> This adds a SPI flash driver which simulates SPI flash clients.
> Currently supports the bare min that U-Boot requires: you can
> probe, read, erase, and write. Should be easy to extend to make
> it behave more exactly like a real SPI flash, but this is good
> enough to merge now.
>
> Signed-off-by: Mike Frysinger <vap...@gentoo.org>
Looks really nice. I have a few nits below.
> ---
> v3
> - rearchitected on top of state/getopt support
>
> drivers/mtd/spi/Makefile | 1 +
> drivers/mtd/spi/sandbox.c | 402
> +++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 403 insertions(+), 0 deletions(-)
> create mode 100644 drivers/mtd/spi/sandbox.c
>
> diff --git a/drivers/mtd/spi/Makefile b/drivers/mtd/spi/Makefile
> index 90f8392..fb37807 100644
> --- a/drivers/mtd/spi/Makefile
> +++ b/drivers/mtd/spi/Makefile
> @@ -33,6 +33,7 @@ COBJS-$(CONFIG_SPI_FLASH) += spi_flash.o
> COBJS-$(CONFIG_SPI_FLASH_ATMEL) += atmel.o
> COBJS-$(CONFIG_SPI_FLASH_EON) += eon.o
> COBJS-$(CONFIG_SPI_FLASH_MACRONIX) += macronix.o
> +COBJS-$(CONFIG_SPI_FLASH_SANDBOX) += sandbox.o
> COBJS-$(CONFIG_SPI_FLASH_SPANSION) += spansion.o
> COBJS-$(CONFIG_SPI_FLASH_SST) += sst.o
> COBJS-$(CONFIG_SPI_FLASH_STMICRO) += stmicro.o
> diff --git a/drivers/mtd/spi/sandbox.c b/drivers/mtd/spi/sandbox.c
> new file mode 100644
> index 0000000..1cbe454
> --- /dev/null
> +++ b/drivers/mtd/spi/sandbox.c
> @@ -0,0 +1,402 @@
> +/*
> + * Simulate a SPI flash
> + *
> + * Copyright (c) 2011-2012 The Chromium OS Authors.
> + * See file CREDITS for list of people who contributed to this
> + * project.
> + *
> + * Licensed under the GPL-2 or later.
> + */
> +
> +#include <common.h>
> +#include <malloc.h>
> +#include <spi.h>
> +#include <os.h>
> +
> +#include <spi_flash.h>
> +#include "spi_flash_internal.h"
> +
> +#include <asm/getopt.h>
> +#include <asm/spi.h>
> +#include <asm/state.h>
> +
> +/*
> + * The different states that our SPI flash transitions between.
> + * We need to keep track of this across multiple xfer calls since
> + * the SPI bus could possibly call down into us multiple times.
> + */
> +typedef enum {
> + SF_CMD, /* default state -- we're awaiting a command */
> + SF_ID, /* read the flash's (jedec) ID code */
> + SF_ADDR, /* processing the offset in the flash to read/etc... */
> + SF_READ, /* reading data from the flash */
> + SF_WRITE, /* writing data to the flash, i.e. page programming */
> + SF_ERASE, /* erase the flash */
> + SF_READ_STATUS, /* read the flash's status register */
> +} sb_sf_state;
> +
> +static const char *sb_sf_state_name(sb_sf_state state)
> +{
> + static const char * const states[] = {
> + "CMD", "ID", "ADDR", "READ", "WRITE", "ERASE", "READ_STATUS",
> + };
> + return states[state];
> +}
> +
> +/* Bits for the status register */
> +#define STAT_WIP (1 << 0)
> +#define STAT_WEL (1 << 1)
> +
> +/* Assume all SPI flashes have 3 byte addresses since they do atm */
> +#define SF_ADDR_LEN 3
> +
> +struct sb_spi_flash_erase_commands {
> + u8 cmd;
> + u32 size;
> +};
> +#define IDCODE_LEN 5
> +#define MAX_ERASE_CMDS 2
> +struct sb_spi_flash_data {
> + const char *name;
> + u8 idcode[IDCODE_LEN];
> + u32 size;
> + const struct sb_spi_flash_erase_commands erase_cmds[MAX_ERASE_CMDS];
> +};
> +
> +/* Structure describing all the flashes we know how to emulate */
> +static const struct sb_spi_flash_data sb_sf_flashes[] = {
> + {
> + "M25P16", { 0x20, 0x20, 0x15 }, (2 * 1024 * 1024),
> + { /* erase commands */
> + { 0xd8, (64 * 1024), }, /* sector */
> + { 0xc7, (2 * 1024 * 1024), }, /* bulk */
> + },
> + },
> +};
> +
> +/* Used to quickly bulk erase backing store */
> +static u8 sb_sf_0xff[0x10000];
Ick, Does it really need to be so large?
> +
> +/* Internal state data for each SPI flash */
> +struct sb_spi_flash {
> + /*
> + * As we receive data over the SPI bus, our flash transitions
> + * between states. For example, we start off in the SF_CMD
> + * state where the first byte tells us what operation to perform
> + * (such as read or write the flash). But the operation itself
> + * can go through a few states such as first reading in the
> + * offset in the flash to perform the requested operation.
> + * Thus "state" stores the exact state that our machine is in
> + * while "cmd" stores the overall command we're processing.
> + */
> + sb_sf_state state;
> + uint cmd;
> + const void *cmd_data;
> + /* Current position in the flash; used when reading/writing/etc... */
> + uint off;
> + /* How many address bytes we've consumed */
> + uint addr_bytes, pad_addr_bytes;
> + /* The current flash status (see STAT_XXX defines above) */
> + u8 status;
> + /* Data describing the flash we're emulating */
> + const struct sb_spi_flash_data *data;
> + /* The file on disk to serv up data from */
> + int fd;
> +};
> +
> +static int sb_sf_setup(void **priv, const char *spec)
> +{
> + /* spec = idcode:file */
> + struct sb_spi_flash *sbsf;
> + const char *file;
> + size_t i, len, idname_len;
> + const struct sb_spi_flash_data *data;
> +
> + file = strchr(spec, ':');
> + if (!file)
> + goto error;
> + idname_len = file - spec;
> + ++file;
> +
> + for (i = 0; i < ARRAY_SIZE(sb_sf_flashes); ++i) {
> + data = &sb_sf_flashes[i];
> + len = strlen(data->name);
> + if (idname_len != len)
> + continue;
> + if (!memcmp(spec, data->name, len))
> + break;
> + }
> + if (i == ARRAY_SIZE(sb_sf_flashes)) {
> + printf("sb_sf: unknown flash '%*s'\n",
> + (int)idname_len, file);
> + goto error;
> + }
> +
> + if (sb_sf_0xff[0] == 0x00)
> + memset(sb_sf_0xff, 0xff, sizeof(sb_sf_0xff));
> +
> + sbsf = malloc(sizeof(*sbsf));
> + if (!sbsf)
> + goto error;
> +
> + sbsf->fd = os_open(file, 02);
> + if (sbsf->fd == -1) {
> + free(sbsf);
> + goto error;
Prints incorrect error if the file couldn't be found/open. I wonder if
we should have os_perror() ?
> + }
> +
> + sbsf->data = data;
> +
> + *priv = sbsf;
> + return 0;
> +
> + error:
> + printf("sb_sf: unable to parse client spec\n");
> + return 1;
> +}
> +
> +static void sb_sf_free(void *priv)
> +{
> + struct sb_spi_flash *sbsf = priv;
> +
> + os_close(sbsf->fd);
> + free(sbsf);
> +}
> +
> +static void sb_sf_cs_activate(void *priv)
> +{
> + struct sb_spi_flash *sbsf = priv;
> +
> + debug("sb_sf: CS activated; state is fresh!\n");
> +
> + /* CS is asserted, so reset state */
> + sbsf->off = 0;
> + sbsf->addr_bytes = 0;
> + sbsf->pad_addr_bytes = 0;
> + sbsf->state = sbsf->cmd = SF_CMD;
> +}
> +
> +static void sb_sf_cs_deactivate(void *priv)
> +{
> + debug("sb_sf: CS deactivated; cmd done processing!\n");
> +}
> +
> +/* Figure out what command this stream is telling us to do */
> +static int sb_sf_process_cmd(struct sb_spi_flash *sbsf, const u8 *rx, u8 *tx)
> +{
> + sb_sf_state oldstate = sbsf->state;
> +
> + /* We need to output a byte for the cmd byte we just ate */
> + sb_spi_tristate(tx, 1);
> +
> + sbsf->cmd = rx[0];
> + switch (sbsf->cmd) {
> + case CMD_READ_ID:
> + sbsf->state = sbsf->cmd = SF_ID;
> + break;
> + case CMD_READ_ARRAY_FAST:
> + sbsf->pad_addr_bytes = 1;
> + case CMD_READ_ARRAY_SLOW:
> + case CMD_PAGE_PROGRAM:
> + state_addr:
> + sbsf->state = SF_ADDR;
> + break;
> + case CMD_WRITE_DISABLE:
> + debug(" write disabled\n");
> + sbsf->status &= ~STAT_WEL;
> + break;
> + case CMD_READ_STATUS:
> + sbsf->state = SF_READ_STATUS;
> + break;
> + case CMD_WRITE_ENABLE:
> + debug(" write enabled\n");
> + sbsf->status |= STAT_WEL;
> + break;
> + default: {
> + size_t i;
> +
> + /* handle erase commands first */
> + for (i = 0; i < MAX_ERASE_CMDS; ++i) {
> + const struct sb_spi_flash_erase_commands *erase_cmd =
> + &sbsf->data->erase_cmds[i];
> +
> + if (erase_cmd->cmd == 0x00)
> + continue;
> + if (sbsf->cmd != erase_cmd->cmd)
> + continue;
> +
> + sbsf->cmd_data = erase_cmd;
> + goto state_addr;
> + }
> +
> + debug(" cmd unknown: %#x\n", sbsf->cmd);
> + return 1;
> + }
> + }
> +
> + if (oldstate != sbsf->state)
> + debug(" cmd: transition to %s state\n",
> + sb_sf_state_name(sbsf->state));
> +
> + return 0;
> +}
> +
> +static int sb_sf_xfer(void *priv, const u8 *rx, u8 *tx,
> + uint bytes)
> +{
> + struct sb_spi_flash *sbsf = priv;
> + uint cnt, pos = 0;
> +
> + debug("sb_sf: state:%x(%s) bytes:%u\n", sbsf->state,
> + sb_sf_state_name(sbsf->state), bytes);
> +
> + if (sbsf->state == SF_CMD) {
> + /* Figure out the initial state */
> + if (sb_sf_process_cmd(sbsf, rx, tx))
> + return 1;
> + ++pos;
> + }
> +
> + /* Process the remaining data */
> + while (pos < bytes) {
> + switch (sbsf->state) {
> + case SF_ID: {
> + u8 id;
> +
> + debug(" id: off:%u tx:", sbsf->off);
> + if (sbsf->off < IDCODE_LEN)
> + id = sbsf->data->idcode[sbsf->off];
> + else
> + id = 0;
> + debug("%02x\n", id);
> + tx[pos++] = id;
> + ++sbsf->off;
> + break;
> + }
> + case SF_ADDR:
> + debug(" addr: bytes:%u rx:%02x ",
> + sbsf->addr_bytes, rx[pos]);
> +
> + if (sbsf->addr_bytes++ < SF_ADDR_LEN)
> + sbsf->off = (sbsf->off << 8) | rx[pos];
> + debug("addr:%06x\n", sbsf->off);
> +
> + sb_spi_tristate(&tx[pos++], 1);
> +
> + /* See if we're done processing */
> + if (sbsf->addr_bytes < SF_ADDR_LEN +
> sbsf->pad_addr_bytes)
> + break;
> +
> + /* Next state! */
> + os_lseek(sbsf->fd, sbsf->off, OS_SEEK_SET);
check error return
> + switch (sbsf->cmd) {
> + case CMD_READ_ARRAY_FAST:
> + case CMD_READ_ARRAY_SLOW:
> + sbsf->state = SF_READ;
> + break;
> + case CMD_PAGE_PROGRAM:
> + sbsf->state = SF_WRITE;
> + break;
> + default:
> + /* assume erase state ... */
> + sbsf->state = SF_ERASE;
> + goto case_SF_ERASE;
> + }
> + debug(" cmd: transition to %s state\n",
> + sb_sf_state_name(sbsf->state));
> + break;
> + case SF_READ:
> + /*
> + * XXX: need to handle exotic behavior:
> + * - reading past end of device
> + */
> +
> + cnt = bytes - pos;
> + debug(" tx: read(%u)\n", cnt);
> + pos += os_read(sbsf->fd, tx + pos, cnt);
This can fail (return -1)
> + break;
> + case SF_READ_STATUS:
> + debug(" read status: %#x\n", sbsf->status);
> + cnt = bytes - pos;
> + memset(tx + pos, sbsf->status, cnt);
> + pos += cnt;
> + break;
> + case SF_WRITE:
> + /*
> + * XXX: need to handle exotic behavior:
> + * - unaligned addresses
> + * - more than a page (256) worth of data
> + * - reading past end of device
> + */
> +
> + if (!(sbsf->status & STAT_WEL)) {
> + puts("sb_sf: write enable not set before
> erase\n");
> + goto done;
> + }
> +
> + cnt = bytes - pos;
> + debug(" rx: write(%u)\n", cnt);
> + sb_spi_tristate(&tx[pos], cnt);
> + pos += os_write(sbsf->fd, rx + pos, cnt);
error return
> + sbsf->status &= ~STAT_WEL;
> + break;
> + case SF_ERASE:
> + case_SF_ERASE: {
> + const struct sb_spi_flash_erase_commands *erase_cmd =
> + sbsf->cmd_data;
> +
> + if (!(sbsf->status & STAT_WEL)) {
> + puts("sb_sf: write enable not set before
> erase\n");
> + goto done;
> + }
> +
> + /* verify address is aligned */
> + if (sbsf->off & ~(erase_cmd->size - 1)) {
> + debug(" sector erase: cmd:%#x needs
> align:%#x, but we got %#x\n",
> + erase_cmd->cmd, erase_cmd->size,
> sbsf->off);
> + sbsf->status &= ~STAT_WEL;
> + goto done;
> + }
> +
> + debug(" sector erase addr: %u\n", sbsf->off);
> +
> + cnt = bytes - pos;
> + sb_spi_tristate(&tx[pos], cnt);
> + pos += cnt;
> +
> + /* XXX: latch WIP in status, and delay before
> clearing it ? */
> + os_write(sbsf->fd, sb_sf_0xff, erase_cmd->size);
Check error return?
> + sbsf->status &= ~STAT_WEL;
> + goto done;
> + }
> + default:
> + debug(" ??? no idea what to do ???\n");
> + goto done;
> + }
> + }
> +
> + done:
> + return pos == bytes ? 0 : 1;
> +}
> +
> +static const struct sb_spi_emu_ops sb_sf_ops = {
> + .setup = sb_sf_setup,
> + .free = sb_sf_free,
> + .cs_activate = sb_sf_cs_activate,
> + .cs_deactivate = sb_sf_cs_deactivate,
> + .xfer = sb_sf_xfer,
> +};
> +
> +static int sb_cmdline_cb_spi_sf(struct sandbox_state *state, const char *arg)
> +{
> + unsigned long bus, cs;
> + const char *spec = sb_spi_parse_spec(arg, &bus, &cs);
> +
> + if (!spec)
> + return 1;
> +
> + state->spi[bus][cs][0] = &sb_sf_ops;
> + state->spi[bus][cs][1] = spec;
> + return 0;
> +}
> +SB_CMDLINE_OPT(spi_sf, 1, "connect a SPI flash: <bus>:<cs>:<id>:<file>");
> --
> 1.7.8.5
>
Regards,
Simon
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