Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753865Ab3F0MyS (ORCPT ); Thu, 27 Jun 2013 08:54:18 -0400 Received: from kdh-gw.itdev.co.uk ([89.21.227.133]:12379 "EHLO hermes.kdh.itdev.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753667Ab3F0Muw (ORCPT ); Thu, 27 Jun 2013 08:50:52 -0400 From: Nick Dyer To: Dmitry Torokhov Cc: Daniel Kurtz , Henrik Rydberg , Joonyoung Shim , Alan Bowens , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Peter Meerwald , Benson Leung , Olof Johansson , Nick Dyer Subject: [PATCH 42/51] Input: atmel_mxt_ts - Verify Information Block checksum on probe Date: Thu, 27 Jun 2013 13:49:17 +0100 Message-Id: <1372337366-9286-43-git-send-email-nick.dyer@itdev.co.uk> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1372337366-9286-1-git-send-email-nick.dyer@itdev.co.uk> References: <1372337366-9286-1-git-send-email-nick.dyer@itdev.co.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10939 Lines: 357 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 Acked-by: Benson Leung --- drivers/input/touchscreen/atmel_mxt_ts.c | 182 ++++++++++++++++++------------ 1 file changed, 112 insertions(+), 70 deletions(-) diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c index c01a457..8827bbd 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; @@ -363,12 +364,16 @@ 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; } @@ -608,7 +613,7 @@ 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; @@ -1245,13 +1250,13 @@ 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; @@ -1298,7 +1303,7 @@ 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); @@ -1506,24 +1511,12 @@ 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; @@ -1545,25 +1538,17 @@ 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; @@ -1587,7 +1572,7 @@ 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); @@ -1647,22 +1632,103 @@ 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; + uint8_t num_objects; + 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 */ + num_objects = ((struct mxt_info *)buf)->object_num; + size += (num_objects * 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", + data->info->family_id, data->info->variant_id, + data->info->version >> 4, data->info->version & 0xf, + data->info->build, data->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; } @@ -1717,13 +1783,12 @@ 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); @@ -1755,21 +1820,6 @@ 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; @@ -1788,17 +1838,6 @@ 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; @@ -1813,9 +1852,9 @@ 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 */ @@ -1823,9 +1862,8 @@ 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, @@ -1862,7 +1900,7 @@ 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)) @@ -2127,6 +2165,10 @@ 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/