By validating the checksum, we can identify if the configuration is corrupt.
In addition, this patch writes the configuration in a short series of block
writes rather than as many individual values.
Signed-off-by: Nick Dyer <nick.d...@itdev.co.uk>
---
drivers/input/touchscreen/atmel_mxt_ts.c | 237 +++++++++++++++++++++---------
1 file changed, 168 insertions(+), 69 deletions(-)
diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c
b/drivers/input/touchscreen/atmel_mxt_ts.c
index d015168..302c03e 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -264,10 +264,12 @@ struct mxt_data {
struct bin_attribute mem_access_attr;
bool debug_enabled;
u32 config_crc;
+ u32 info_crc;
/* Cached parameters from object table */
u8 T6_reportid;
u16 T6_address;
+ u16 T7_address;
u8 T9_reportid_min;
u8 T9_reportid_max;
};
@@ -673,6 +675,45 @@ static void mxt_read_current_crc(struct mxt_data *data)
mxt_process_messages_until_invalid(data);
}
+static void mxt_calc_crc24(u32 *crc, u8 firstbyte, u8 secondbyte)
+{
+ static const unsigned int crcpoly = 0x80001B;
+ u32 result;
+ u32 data_word;
+
+ data_word = (secondbyte << 8) | firstbyte;
+ result = ((*crc << 1) ^ data_word);
+
+ if (result & 0x1000000)
+ result ^= crcpoly;
+
+ *crc = result;
+}
+
+static u32 mxt_calculate_crc(u8 *base, off_t start_off, off_t end_off)
+{
+ u32 crc = 0;
+ u8 *ptr = base + start_off;
+ u8 *last_val = base + end_off - 1;
+
+ if (end_off < start_off)
+ return -EINVAL;
+
+ while (ptr < last_val) {
+ mxt_calc_crc24(&crc, *ptr, *(ptr + 1));
+ ptr += 2;
+ }
+
+ /* if len is odd, fill the last byte with 0 */
+ if (ptr == last_val)
+ mxt_calc_crc24(&crc, *ptr, 0);
+
+ /* Mask to 24-bit */
+ crc &= 0x00FFFFFF;
+
+ return crc;
+}
+
static int mxt_check_reg_init(struct mxt_data *data)
{
struct device *dev = &data->client->dev;
@@ -681,9 +722,13 @@ static int mxt_check_reg_init(struct mxt_data *data)
const struct firmware *cfg = NULL;
int ret;
int offset;
- int pos;
+ int data_pos;
+ int byte_offset;
int i;
- u32 info_crc, config_crc;
+ int config_start_offset;
+ u32 info_crc, config_crc, calculated_crc;
+ u8 *config_mem;
+ size_t config_mem_size;
unsigned int type, instance, size;
u8 val;
u16 reg;
@@ -703,11 +748,11 @@ static int mxt_check_reg_init(struct mxt_data *data)
goto release;
}
- pos = strlen(MXT_CFG_MAGIC);
+ data_pos = strlen(MXT_CFG_MAGIC);
/* Load information block and check */
for (i = 0; i < sizeof(struct mxt_info); i++) {
- ret = sscanf(cfg->data + pos, "%hhx%n",
+ ret = sscanf(cfg->data + data_pos, "%hhx%n",
(unsigned char *)&cfg_info + i,
&offset);
if (ret != 1) {
@@ -716,132 +761,183 @@ static int mxt_check_reg_init(struct mxt_data *data)
goto release;
}
- pos += offset;
+ data_pos += offset;
}
- if (cfg_info.family_id != data->info.family_id) {
- dev_err(dev, "Family ID mismatch!\n");
- ret = -EINVAL;
- goto release;
- }
-
- if (cfg_info.variant_id != data->info.variant_id) {
- dev_err(dev, "Variant ID mismatch!\n");
- ret = -EINVAL;
- goto release;
- }
-
- if (cfg_info.version != data->info.version)
- dev_err(dev, "Warning: version mismatch!\n");
-
- if (cfg_info.build != data->info.build)
- dev_err(dev, "Warning: build num mismatch!\n");
-
- ret = sscanf(cfg->data + pos, "%x%n", &info_crc, &offset);
+ /* Read CRCs */
+ ret = sscanf(cfg->data + data_pos, "%x%n", &info_crc, &offset);
if (ret != 1) {
dev_err(dev, "Bad format: failed to parse Info CRC\n");
ret = -EINVAL;
goto release;
}
- pos += offset;
+ data_pos += offset;
- /* Check config CRC */
- ret = sscanf(cfg->data + pos, "%x%n", &config_crc, &offset);
+ ret = sscanf(cfg->data + data_pos, "%x%n", &config_crc, &offset);
if (ret != 1) {
dev_err(dev, "Bad format: failed to parse Config CRC\n");
ret = -EINVAL;
goto release;
}
- pos += offset;
+ data_pos += offset;
+
+ /* The Info Block CRC is calculated over mxt_info and the object table
+ * If it does not match then we are trying to load the configuration
+ * from a different chip or firmware version, so the configuration CRC
+ * is invalid anyway. */
+ if (info_crc == data->info_crc) {
+ if (config_crc == 0 || data->config_crc == 0) {
+ dev_info(dev, "CRC zero, attempting to apply config\n");
+ } else if (config_crc == data->config_crc) {
+ dev_info(dev, "Config CRC 0x%06X: OK\n",
data->config_crc);
+ ret = 0;
+ goto release;
+ } else {
+ dev_info(dev, "Config CRC 0x%06X: does not match file
0x%06X\n",
+ data->config_crc, config_crc);
+ }
+ } else {
+ dev_warn(dev,
+ "Warning: Info CRC error - device=0x%06X
file=0x%06X\n",
+ data->info_crc, info_crc);
+ }
- if (data->config_crc == config_crc) {
- dev_info(dev, "Config CRC 0x%06X: OK\n", config_crc);
- ret = 0;
+ /* Malloc memory to store configuration */
+ config_start_offset = MXT_OBJECT_START
+ + data->info.object_num * sizeof(struct mxt_object);
+ config_mem_size = data->mem_size - config_start_offset;
+ config_mem = kzalloc(config_mem_size, GFP_KERNEL);
+ if (!config_mem) {
+ dev_err(dev, "Failed to allocate memory\n");
+ ret = -ENOMEM;
goto release;
- } else {
- dev_info(dev, "Config CRC 0x%06X: does not match file 0x%06X\n",
- data->config_crc, config_crc);
}
- while (pos < cfg->size) {
+ while (data_pos < cfg->size) {
/* Read type, instance, length */
- ret = sscanf(cfg->data + pos, "%x %x %x%n",
+ ret = sscanf(cfg->data + data_pos, "%x %x %x%n",
&type, &instance, &size, &offset);
if (ret == 0) {
/* EOF */
- ret = 1;
- goto release;
+ break;
} else if (ret != 3) {
dev_err(dev, "Bad format: failed to parse object\n");
ret = -EINVAL;
- goto release;
+ goto release_mem;
}
- pos += offset;
+ data_pos += offset;
object = mxt_get_object(data, type);
if (!object) {
ret = -EINVAL;
- goto release;
- }
-
- if (size > OBP_SIZE(object)) {
- dev_err(dev, "Object length exceeded!\n");
- ret = -EINVAL;
- goto release;
+ goto release_mem;
}
if (instance >= OBP_INSTANCES(object)) {
dev_err(dev, "Object instances exceeded!\n");
ret = -EINVAL;
- goto release;
+ goto release_mem;
}
reg = object->start_address + OBP_SIZE(object) * instance;
+ if (size > OBP_SIZE(object)) {
+ /* Either we are in fallback mode due to wrong
+ * config or config from a later fw version,
+ * or the file is corrupt or hand-edited */
+ dev_warn(dev, "Discarding %u bytes in T%u!\n",
+ size - OBP_SIZE(object), type);
+
+ size = OBP_SIZE(object);
+ } else if (OBP_SIZE(object) > size) {
+ /* If firmware is upgraded, new bytes may be added to
+ * end of objects. It is generally forward compatible
+ * to zero these bytes - previous behaviour will be
+ * retained. However this does invalidate the CRC and
+ * will force fallback mode until the configuration is
+ * updated. We warn here but do nothing else - the
+ * malloc has zeroed the entire configuration. */
+ dev_warn(dev, "Zeroing %d byte(s) in T%d\n",
+ OBP_SIZE(object) - size, type);
+ }
+
for (i = 0; i < size; i++) {
- ret = sscanf(cfg->data + pos, "%hhx%n",
+ ret = sscanf(cfg->data + data_pos, "%hhx%n",
&val,
&offset);
if (ret != 1) {
dev_err(dev, "Bad format in T%d\n", type);
ret = -EINVAL;
- goto release;
+ goto release_mem;
}
- ret = mxt_write_reg(data->client, reg + i, val);
- if (ret)
- goto release;
+ byte_offset = reg + i - config_start_offset;
+
+ if ((byte_offset >= 0)
+ && (byte_offset <= config_mem_size)) {
+ *(config_mem + byte_offset) = val;
+ } else {
+ dev_err(dev, "Bad object: reg:%d, T%d,
ofs=%d\n",
+ reg, object->type, byte_offset);
+ ret = -EINVAL;
+ goto release_mem;
+ }
- pos += offset;
+ data_pos += offset;
}
- /* If firmware is upgraded, new bytes may be added to end of
- * objects. It is generally forward compatible to zero these
- * bytes - previous behaviour will be retained. However
- * this does invalidate the CRC and will force a config
- * download every time until the configuration is updated */
- if (size < OBP_SIZE(object)) {
- dev_info(dev, "Warning: zeroing %d byte(s) in T%d\n",
- OBP_SIZE(object) - size, type);
+ }
- for (i = size + 1; i < OBP_SIZE(object); i++) {
- ret = mxt_write_reg(data->client, reg + i, 0);
- if (ret)
- goto release;
- }
+ /* calculate crc of the received configs (not the raw config file) */
+ if (data->T7_address < config_start_offset) {
+ dev_err(dev, "Bad T7 address, T7addr = %x, config offset %x\n",
+ data->T7_address, config_start_offset);
+ ret = 0;
+ goto release_mem;
+ }
+
+ calculated_crc = mxt_calculate_crc(config_mem,
+ data->T7_address - config_start_offset,
config_mem_size);
+
+ /* check the crc, calculated should same as what's in file */
+ if (config_crc > 0 && (config_crc != calculated_crc)) {
+ dev_err(dev, "CRC mismatch in config file, calculated=%06X,
file=%06X\n",
+ calculated_crc, config_crc);
+ ret = 0;
+ goto release_mem;
+ }
+
+ /* Write configuration as blocks */
+ byte_offset = 0;
+ while (byte_offset < config_mem_size) {
+ size = config_mem_size - byte_offset;
+
+ if (size > MXT_MAX_BLOCK_WRITE)
+ size = MXT_MAX_BLOCK_WRITE;
+
+ ret = __mxt_write_reg(data->client,
+ config_start_offset + byte_offset,
+ size, config_mem + byte_offset);
+ if (ret != 0) {
+ dev_err(dev, "Config write error, ret=%d\n", ret);
+ goto release_mem;
}
+
+ byte_offset += size;
}
ret = mxt_t6_command(data, MXT_COMMAND_BACKUPNV, MXT_BACKUP_VALUE,
false);
if (ret)
- goto release;
+ goto release_mem;
ret = mxt_soft_reset(data, MXT_RESET_VALUE);
if (ret)
- goto release;
+ goto release_mem;
dev_info(dev, "Config written\n");
+release_mem:
+ kfree(config_mem);
release:
release_firmware(cfg);
return ret;
@@ -927,6 +1023,9 @@ static int mxt_get_object_table(struct mxt_data *data)
data->T6_reportid = min_id;
data->T6_address = object->start_address;
break;
+ case MXT_GEN_POWER_T7:
+ data->T7_address = object->start_address;
+ break;
case MXT_TOUCH_MULTI_T9:
data->T9_reportid_min = min_id;
data->T9_reportid_max = max_id;
--
1.7.10.4
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