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Message-Id: <1370453866-16534-45-git-send-email-nick.dyer@itdev.co.uk>
Date: Wed, 5 Jun 2013 18:37:37 +0100
From: Nick Dyer <nick.dyer@...ev.co.uk>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>,
Daniel Kurtz <djkurtz@...omium.org>,
Henrik Rydberg <rydberg@...omail.se>,
Joonyoung Shim <jy0922.shim@...sung.com>,
Alan.Bowens@...el.com, linux-input@...r.kernel.org,
linux-kernel@...r.kernel.org, pmeerw@...erw.net,
bleung@...omium.org, olofj@...omium.org
Cc: Nick Dyer <nick.dyer@...ev.co.uk>
Subject: [PATCH 44/53] Input: atmel_mxt_ts - Verify Information Block checksum on probe
By reading the information block and the object table into a contiguous region
of memory, we can verify the checksum at probe time. This means we verify that
we are indeed talking to a chip that supports object protocol correctly. We
also detect I2C comms problems much earlier, resulting in easier diagnosis.
Signed-off-by: Nick Dyer <nick.dyer@...ev.co.uk>
Acked-by: Benson Leung <bleung@...omium.org>
---
drivers/input/touchscreen/atmel_mxt_ts.c | 181 ++++++++++++++++++------------
1 file changed, 111 insertions(+), 70 deletions(-)
diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index bbfea7a..e0ff017 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -194,7 +194,8 @@ struct mxt_data {
char phys[64]; /* device physical location */
struct mxt_platform_data *pdata;
struct mxt_object *object_table;
- struct mxt_info info;
+ struct mxt_info *info;
+ void *raw_info_block;
unsigned int irq;
unsigned int max_x;
unsigned int max_y;
@@ -365,12 +366,16 @@ static int mxt_lookup_bootloader_address(struct mxt_data *data, bool retry)
{
u8 appmode = data->client->addr;
u8 bootloader;
+ u8 family_id = 0;
+
+ if (data->info)
+ family_id = data->info->family_id;
switch (appmode) {
case 0x4a:
case 0x4b:
/* Chips after 1664S use different scheme */
- if (retry || data->info.family_id >= 0xa2) {
+ if (retry || family_id >= 0xa2) {
bootloader = appmode - 0x24;
break;
}
@@ -610,7 +615,7 @@ mxt_get_object(struct mxt_data *data, u8 type)
struct mxt_object *object;
int i;
- for (i = 0; i < data->info.object_num; i++) {
+ for (i = 0; i < data->info->object_num; i++) {
object = data->object_table + i;
if (object->type == type)
return object;
@@ -1249,13 +1254,13 @@ static int mxt_check_reg_init(struct mxt_data *data)
data_pos += offset;
}
- if (cfg_info.family_id != data->info.family_id) {
+ 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) {
+ if (cfg_info.variant_id != data->info->variant_id) {
dev_err(dev, "Variant ID mismatch!\n");
ret = -EINVAL;
goto release;
@@ -1302,7 +1307,7 @@ static int mxt_check_reg_init(struct mxt_data *data)
/* Malloc memory to store configuration */
cfg_start_ofs = MXT_OBJECT_START
- + data->info.object_num * sizeof(struct mxt_object)
+ + data->info->object_num * sizeof(struct mxt_object)
+ MXT_INFO_CHECKSUM_SIZE;
config_mem_size = data->mem_size - cfg_start_ofs;
config_mem = kzalloc(config_mem_size, GFP_KERNEL);
@@ -1510,24 +1515,12 @@ static int mxt_acquire_irq(struct mxt_data *data)
return 0;
}
-static int mxt_get_info(struct mxt_data *data)
-{
- struct i2c_client *client = data->client;
- struct mxt_info *info = &data->info;
- int error;
-
- /* Read 7-byte info block starting at address 0 */
- error = __mxt_read_reg(client, 0, sizeof(*info), info);
- if (error)
- return error;
-
- return 0;
-}
-
static void mxt_free_object_table(struct mxt_data *data)
{
- kfree(data->object_table);
+ kfree(data->raw_info_block);
data->object_table = NULL;
+ data->info = NULL;
+ data->raw_info_block = NULL;
kfree(data->msg_buf);
data->msg_buf = NULL;
data->enable_reporting = false;
@@ -1549,25 +1542,17 @@ static void mxt_free_object_table(struct mxt_data *data)
data->max_reportid = 0;
}
-static int mxt_get_object_table(struct mxt_data *data)
+static int mxt_parse_object_table(struct mxt_data *data)
{
struct i2c_client *client = data->client;
- size_t table_size;
- int error;
int i;
u8 reportid;
u16 end_address;
- table_size = data->info.object_num * sizeof(struct mxt_object);
- error = __mxt_read_reg(client, MXT_OBJECT_START, table_size,
- data->object_table);
- if (error)
- return error;
-
/* Valid Report IDs start counting from 1 */
reportid = 1;
data->mem_size = 0;
- for (i = 0; i < data->info.object_num; i++) {
+ for (i = 0; i < data->info->object_num; i++) {
struct mxt_object *object = data->object_table + i;
u8 min_id, max_id;
@@ -1591,7 +1576,7 @@ static int mxt_get_object_table(struct mxt_data *data)
switch (object->type) {
case MXT_GEN_MESSAGE_T5:
- if (data->info.family_id == 0x80) {
+ if (data->info->family_id == 0x80) {
/* On mXT224 read and discard unused CRC byte
* otherwise DMA reads are misaligned */
data->T5_msg_size = mxt_obj_size(object);
@@ -1651,22 +1636,102 @@ static int mxt_get_object_table(struct mxt_data *data)
/* If T44 exists, T5 position has to be directly after */
if (data->T44_address && (data->T5_address != data->T44_address + 1)) {
dev_err(&client->dev, "Invalid T44 position\n");
- error = -EINVAL;
- goto free_object_table;
+ return -EINVAL;
}
data->msg_buf = kcalloc(data->max_reportid,
data->T5_msg_size, GFP_KERNEL);
if (!data->msg_buf) {
dev_err(&client->dev, "Failed to allocate message buffer\n");
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static int mxt_read_info_block(struct mxt_data *data)
+{
+ struct i2c_client *client = data->client;
+ int error;
+ size_t size;
+ void *buf;
+ struct mxt_info *info;
+ u32 calculated_crc;
+ u8 *crc_ptr;
+
+ /* If info block already allocated, free it */
+ if (data->raw_info_block != NULL)
+ mxt_free_object_table(data);
+
+ /* Read 7-byte ID information block starting at address 0 */
+ size = sizeof(struct mxt_info);
+ buf = kzalloc(size, GFP_KERNEL);
+ if (!buf) {
+ dev_err(&client->dev, "Failed to allocate memory\n");
+ return -ENOMEM;
+ }
+
+ error = __mxt_read_reg(client, 0, size, buf);
+ if (error)
+ goto err_free_mem;
+
+ /* Resize buffer to give space for rest of info block */
+ info = (struct mxt_info *)buf;
+ size += (info->object_num * sizeof(struct mxt_object))
+ + MXT_INFO_CHECKSUM_SIZE;
+
+ buf = krealloc(buf, size, GFP_KERNEL);
+ if (!buf) {
+ dev_err(&client->dev, "Failed to allocate memory\n");
error = -ENOMEM;
- goto free_object_table;
+ goto err_free_mem;
+ }
+
+ /* Read rest of info block */
+ error = __mxt_read_reg(client, MXT_OBJECT_START,
+ size - MXT_OBJECT_START,
+ buf + MXT_OBJECT_START);
+ if (error)
+ goto err_free_mem;
+
+ /* Extract & calculate checksum */
+ crc_ptr = buf + size - MXT_INFO_CHECKSUM_SIZE;
+ data->info_crc = crc_ptr[0] | (crc_ptr[1] << 8) | (crc_ptr[2] << 16);
+
+ calculated_crc = mxt_calculate_crc(buf, 0,
+ size - MXT_INFO_CHECKSUM_SIZE);
+
+ /* CRC mismatch can be caused by data corruption due to I2C comms
+ * issue or else device is not using Object Based Protocol */
+ if ((data->info_crc == 0) || (data->info_crc != calculated_crc)) {
+ dev_err(&client->dev,
+ "Info Block CRC error calculated=0x%06X read=0x%06X\n",
+ data->info_crc, calculated_crc);
+ return -EIO;
+ }
+
+ /* Save pointers in device data structure */
+ data->raw_info_block = buf;
+ data->info = (struct mxt_info *)buf;
+ data->object_table = (struct mxt_object *)(buf + MXT_OBJECT_START);
+
+ dev_info(&client->dev,
+ "Family: %u Variant: %u Firmware V%u.%u.%02X Objects: %u\n",
+ info->family_id, info->variant_id, info->version >> 4,
+ info->version & 0xf, info->build, info->object_num);
+
+ /* Parse object table information */
+ error = mxt_parse_object_table(data);
+ if (error) {
+ dev_err(&client->dev, "Error %d reading object table\n", error);
+ mxt_free_object_table(data);
+ return error;
}
return 0;
-free_object_table:
- mxt_free_object_table(data);
+err_free_mem:
+ kfree(buf);
return error;
}
@@ -1721,13 +1786,12 @@ static int mxt_read_t9_resolution(struct mxt_data *data)
static int mxt_initialize(struct mxt_data *data)
{
struct i2c_client *client = data->client;
- struct mxt_info *info = &data->info;
int error;
bool alt_bootloader_addr = false;
bool retry = false;
retry_info:
- error = mxt_get_info(data);
+ error = mxt_read_info_block(data);
if (error) {
retry_bootloader:
error = mxt_probe_bootloader(data, alt_bootloader_addr);
@@ -1759,21 +1823,6 @@ retry_bootloader:
}
}
- data->object_table = kcalloc(info->object_num,
- sizeof(struct mxt_object),
- GFP_KERNEL);
- if (!data->object_table) {
- dev_err(&client->dev, "Failed to allocate memory\n");
- return -ENOMEM;
- }
-
- /* Get object table information */
- error = mxt_get_object_table(data);
- if (error) {
- dev_err(&client->dev, "Error %d reading object table\n", error);
- goto err_free_object_table;
- }
-
error = mxt_acquire_irq(data);
if (error)
goto err_free_object_table;
@@ -1792,17 +1841,6 @@ retry_bootloader:
goto err_free_object_table;
}
- error = mxt_read_t9_resolution(data);
- if (error) {
- dev_err(&client->dev, "Failed to initialize T9 resolution\n");
- goto err_free_object_table;
- }
-
- dev_info(&client->dev,
- "Family: %u Variant: %u Firmware V%u.%u.%02X Objects: %u\n",
- info->family_id, info->variant_id, info->version >> 4,
- info->version & 0xf, info->build, info->object_num);
-
data->enable_reporting = true;
return 0;
@@ -1817,9 +1855,9 @@ static ssize_t mxt_fw_version_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct mxt_data *data = dev_get_drvdata(dev);
- struct mxt_info *info = &data->info;
return scnprintf(buf, PAGE_SIZE, "%u.%u.%02X\n",
- info->version >> 4, info->version & 0xf, info->build);
+ data->info->version >> 4, data->info->version & 0xf,
+ data->info->build);
}
/* Hardware Version is returned as FamilyID.VariantID */
@@ -1827,9 +1865,8 @@ static ssize_t mxt_hw_version_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct mxt_data *data = dev_get_drvdata(dev);
- struct mxt_info *info = &data->info;
return scnprintf(buf, PAGE_SIZE, "%u.%u\n",
- info->family_id, info->variant_id);
+ data->info->family_id, data->info->variant_id);
}
static ssize_t mxt_show_instance(char *buf, int count,
@@ -1866,7 +1903,7 @@ static ssize_t mxt_object_show(struct device *dev,
return -ENOMEM;
error = 0;
- for (i = 0; i < data->info.object_num; i++) {
+ for (i = 0; i < data->info->object_num; i++) {
object = data->object_table + i;
if (!mxt_object_readable(object->type))
@@ -2211,6 +2248,10 @@ static int mxt_initialize_t9_input_device(struct mxt_data *data)
unsigned int mt_flags = 0;
int i;
+ error = mxt_read_t9_resolution(data);
+ if (error)
+ dev_warn(dev, "Failed to initialize T9 resolution\n");
+
input_dev = input_allocate_device();
if (!input_dev) {
dev_err(dev, "Failed to allocate memory\n");
--
1.7.10.4
--
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