watchdog: ziirave_wdt: Don't try to program readonly flash

Bootloader code will ignore any attempts to write data to any flash
area outside of [ZIIRAVE_FIRM_FLASH_MEMORY_START;
ZIIRAVE_FIRM_FLASH_MEMORY_END]. Firmware update code already have an
appropriate check to skip those areas when validating updated
firmware. Firmware programming code, OTOH, does not and will
needlessly send no-op I2C traffic. Add an appropriate check to
__ziirave_firm_write_pkt() so as to save all of that wasted effort.

While at it, normalize all of the address handling code to use full
32-bit address in units of bytes and convert it to an appropriate
value only in places where that is necessary.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Rick Ramstetter <rick@anteaterllc.com>
Cc: linux-watchdog@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20190812200906.31344-15-andrew.smirnov@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
This commit is contained in:
Andrey Smirnov 2019-08-12 13:08:58 -07:00 committed by Wim Van Sebroeck
parent de88053807
commit d2ddc4505e
1 changed files with 24 additions and 9 deletions

View File

@ -51,8 +51,8 @@ static char *ziirave_reasons[] = {"power cycle", "hw watchdog", NULL, NULL,
#define ZIIRAVE_FIRM_PKT_TOTAL_SIZE 20 #define ZIIRAVE_FIRM_PKT_TOTAL_SIZE 20
#define ZIIRAVE_FIRM_PKT_DATA_SIZE 16 #define ZIIRAVE_FIRM_PKT_DATA_SIZE 16
#define ZIIRAVE_FIRM_FLASH_MEMORY_START 0x1600 #define ZIIRAVE_FIRM_FLASH_MEMORY_START (2 * 0x1600)
#define ZIIRAVE_FIRM_FLASH_MEMORY_END 0x2bbf #define ZIIRAVE_FIRM_FLASH_MEMORY_END (2 * 0x2bbf)
#define ZIIRAVE_FIRM_PAGE_SIZE 128 #define ZIIRAVE_FIRM_PAGE_SIZE 128
/* Received and ready for next Download packet. */ /* Received and ready for next Download packet. */
@ -195,12 +195,13 @@ static int ziirave_firm_wait_for_ack(struct watchdog_device *wdd)
return ret == ZIIRAVE_FIRM_DOWNLOAD_ACK ? 0 : -EIO; return ret == ZIIRAVE_FIRM_DOWNLOAD_ACK ? 0 : -EIO;
} }
static int ziirave_firm_set_read_addr(struct watchdog_device *wdd, u16 addr) static int ziirave_firm_set_read_addr(struct watchdog_device *wdd, u32 addr)
{ {
struct i2c_client *client = to_i2c_client(wdd->parent); struct i2c_client *client = to_i2c_client(wdd->parent);
const u16 addr16 = (u16)addr / 2;
u8 address[2]; u8 address[2];
put_unaligned_le16(addr, address); put_unaligned_le16(addr16, address);
return i2c_smbus_write_block_data(client, return i2c_smbus_write_block_data(client,
ZIIRAVE_CMD_DOWNLOAD_SET_READ_ADDR, ZIIRAVE_CMD_DOWNLOAD_SET_READ_ADDR,
@ -234,6 +235,12 @@ static int ziirave_firm_write_byte(struct watchdog_device *wdd, u8 command,
wait_for_ack); wait_for_ack);
} }
static bool ziirave_firm_addr_readonly(u32 addr)
{
return addr < ZIIRAVE_FIRM_FLASH_MEMORY_START ||
addr > ZIIRAVE_FIRM_FLASH_MEMORY_END;
}
/* /*
* ziirave_firm_write_pkt() - Build and write a firmware packet * ziirave_firm_write_pkt() - Build and write a firmware packet
* *
@ -261,6 +268,16 @@ static int __ziirave_firm_write_pkt(struct watchdog_device *wdd,
return -EMSGSIZE; return -EMSGSIZE;
} }
/*
* Ignore packets that are targeting program memory outisde of
* app partition, since they will be ignored by the
* bootloader. At the same time, we need to make sure we'll
* allow zero length packet that will be sent as the last step
* of firmware update
*/
if (len && ziirave_firm_addr_readonly(addr))
return 0;
/* Packet length */ /* Packet length */
packet[0] = len; packet[0] = len;
/* Packet address */ /* Packet address */
@ -279,7 +296,7 @@ static int __ziirave_firm_write_pkt(struct watchdog_device *wdd,
if (ret) if (ret)
dev_err(&client->dev, dev_err(&client->dev,
"Failed to write firmware packet at address 0x%04x: %d\n", "Failed to write firmware packet at address 0x%04x: %d\n",
addr16, ret); addr, ret);
return ret; return ret;
} }
@ -315,14 +332,12 @@ static int ziirave_firm_verify(struct watchdog_device *wdd,
const struct ihex_binrec *rec; const struct ihex_binrec *rec;
int i, ret; int i, ret;
u8 data[ZIIRAVE_FIRM_PKT_DATA_SIZE]; u8 data[ZIIRAVE_FIRM_PKT_DATA_SIZE];
u16 addr;
for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) { for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
const u16 len = be16_to_cpu(rec->len); const u16 len = be16_to_cpu(rec->len);
const u32 addr = be32_to_cpu(rec->addr);
addr = (be32_to_cpu(rec->addr) & 0xffff) >> 1; if (ziirave_firm_addr_readonly(addr))
if (addr < ZIIRAVE_FIRM_FLASH_MEMORY_START ||
addr > ZIIRAVE_FIRM_FLASH_MEMORY_END)
continue; continue;
ret = ziirave_firm_set_read_addr(wdd, addr); ret = ziirave_firm_set_read_addr(wdd, addr);