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Subject[PATCH] PTI feature to allow user to name and mark masterchannel request.
Date
From: J Freyensee <james_p_freyensee@linux.intel.com>

This feature addition provides a new parameter in
pti_request_masterchannel() to allow the user
to provide their own name to mark the request when
the trace is viewed in a PTI SW trace viewer
(like MPTA). If a name is not provided and
NULL is provided, the 'current' process name is used.
API function header documentation documents this.

Signed-off-by: Jeremy Rocher <rocher.jeremy@gmail.com>
Signed-off-by: J Freyensee <james_p_freyensee@linux.intel.com>
---
drivers/misc/pti.c | 99 +++++++++++++++++++++++++++++++--------------------
include/linux/pti.h | 3 +-
2 files changed, 62 insertions(+), 40 deletions(-)

diff --git a/drivers/misc/pti.c b/drivers/misc/pti.c
index e5f295a..8653bd0 100644
--- a/drivers/misc/pti.c
+++ b/drivers/misc/pti.c
@@ -146,45 +146,54 @@ static void pti_write_to_aperture(struct pti_masterchannel *mc,
/**
* pti_control_frame_built_and_sent()- control frame build and send function.
*
- * @mc: The master / channel structure on which the function
- * built a control frame.
+ * @mc: The master / channel structure on which the function
+ * built a control frame.
+ * @thread_name: The thread name associated with the master / channel or
+ * 'NULL' if using the 'current' global variable.
*
* To be able to post process the PTI contents on host side, a control frame
* is added before sending any PTI content. So the host side knows on
* each PTI frame the name of the thread using a dedicated master / channel.
- * The thread name is retrieved from the 'current' global variable.
+ * The thread name is retrieved from 'current' global variable if 'thread_name'
+ * is 'NULL', else it is retrieved from 'thread_name' parameter.
* This function builds this frame and sends it to a master ID CONTROL_ID.
* The overhead is only 32 bytes since the driver only writes to HW
* in 32 byte chunks.
*/
-
-static void pti_control_frame_built_and_sent(struct pti_masterchannel *mc)
+static void pti_control_frame_built_and_sent(struct pti_masterchannel *mc,
+ const char *thread_name)
{
struct pti_masterchannel mccontrol = {.master = CONTROL_ID,
.channel = 0};
+ const char *thread_name_p;
const char *control_format = "%3d %3d %s";
u8 control_frame[CONTROL_FRAME_LEN];

- /*
- * Since we access the comm member in current's task_struct,
- * we only need to be as large as what 'comm' in that
- * structure is.
- */
- char comm[TASK_COMM_LEN];
+ if (!thread_name) {
+ /*
+ * Since we access the comm member in current's task_struct,
+ * we only need to be as large as what 'comm' in that
+ * structure is.
+ */
+ char comm[TASK_COMM_LEN];

- if (!in_interrupt())
- get_task_comm(comm, current);
- else
- strncpy(comm, "Interrupt", TASK_COMM_LEN);
+ if (!in_interrupt())
+ get_task_comm(comm, current);
+ else
+ strncpy(comm, "Interrupt", TASK_COMM_LEN);

- /* Absolutely ensure our buffer is zero terminated. */
- comm[TASK_COMM_LEN-1] = 0;
+ /* Absolutely ensure our buffer is zero terminated. */
+ comm[TASK_COMM_LEN-1] = 0;
+ thread_name_p = comm;
+ } else {
+ thread_name_p = thread_name;
+ }

mccontrol.channel = pti_control_channel;
pti_control_channel = (pti_control_channel + 1) & 0x7f;

snprintf(control_frame, CONTROL_FRAME_LEN, control_format, mc->master,
- mc->channel, comm);
+ mc->channel, thread_name_p);
pti_write_to_aperture(&mccontrol, control_frame, strlen(control_frame));
}

@@ -206,18 +215,20 @@ static void pti_write_full_frame_to_aperture(struct pti_masterchannel *mc,
const unsigned char *buf,
int len)
{
- pti_control_frame_built_and_sent(mc);
+ pti_control_frame_built_and_sent(mc, NULL);
pti_write_to_aperture(mc, (u8 *)buf, len);
}

/**
* get_id()- Allocate a master and channel ID.
*
- * @id_array: an array of bits representing what channel
- * id's are allocated for writing.
- * @max_ids: The max amount of available write IDs to use.
- * @base_id: The starting SW channel ID, based on the Intel
- * PTI arch.
+ * @id_array: an array of bits representing what channel
+ * id's are allocated for writing.
+ * @max_ids: The max amount of available write IDs to use.
+ * @base_id: The starting SW channel ID, based on the Intel
+ * PTI arch.
+ * @thread_name: The thread name associated with the master / channel or
+ * 'NULL' if using the 'current' global variable.
*
* Returns:
* pti_masterchannel struct with master, channel ID address
@@ -227,7 +238,10 @@ static void pti_write_full_frame_to_aperture(struct pti_masterchannel *mc,
* channel id. The bit is one if the id is taken and 0 if free. For
* every master there are 128 channel id's.
*/
-static struct pti_masterchannel *get_id(u8 *id_array, int max_ids, int base_id)
+static struct pti_masterchannel *get_id(u8 *id_array,
+ int max_ids,
+ int base_id,
+ const char *thread_name)
{
struct pti_masterchannel *mc;
int i, j, mask;
@@ -257,7 +271,7 @@ static struct pti_masterchannel *get_id(u8 *id_array, int max_ids, int base_id)
mc->master = base_id;
mc->channel = ((i & 0xf)<<3) + j;
/* write new master Id / channel Id allocation to channel control */
- pti_control_frame_built_and_sent(mc);
+ pti_control_frame_built_and_sent(mc, thread_name);
return mc;
}

@@ -273,18 +287,22 @@ static struct pti_masterchannel *get_id(u8 *id_array, int max_ids, int base_id)
* a master, channel ID address
* to write to PTI HW.
*
- * @type: 0- request Application master, channel aperture ID write address.
- * 1- request OS master, channel aperture ID write
- * address.
- * 2- request Modem master, channel aperture ID
- * write address.
- * Other values, error.
+ * @type: 0- request Application master, channel aperture ID
+ * write address.
+ * 1- request OS master, channel aperture ID write
+ * address.
+ * 2- request Modem master, channel aperture ID
+ * write address.
+ * Other values, error.
+ * @thread_name: The thread name associated with the master / channel or
+ * 'NULL' if using the 'current' global variable.
*
* Returns:
* pti_masterchannel struct
* 0 for error
*/
-struct pti_masterchannel *pti_request_masterchannel(u8 type)
+struct pti_masterchannel *pti_request_masterchannel(u8 type,
+ const char *thread_name)
{
struct pti_masterchannel *mc;

@@ -293,15 +311,18 @@ struct pti_masterchannel *pti_request_masterchannel(u8 type)
switch (type) {

case 0:
- mc = get_id(drv_data->ia_app, MAX_APP_IDS, APP_BASE_ID);
+ mc = get_id(drv_data->ia_app, MAX_APP_IDS,
+ APP_BASE_ID, thread_name);
break;

case 1:
- mc = get_id(drv_data->ia_os, MAX_OS_IDS, OS_BASE_ID);
+ mc = get_id(drv_data->ia_os, MAX_OS_IDS,
+ OS_BASE_ID, thread_name);
break;

case 2:
- mc = get_id(drv_data->ia_modem, MAX_MODEM_IDS, MODEM_BASE_ID);
+ mc = get_id(drv_data->ia_modem, MAX_MODEM_IDS,
+ MODEM_BASE_ID, thread_name);
break;
default:
mc = NULL;
@@ -472,9 +493,9 @@ static int pti_tty_install(struct tty_driver *driver, struct tty_struct *tty)
return -ENOMEM;

if (idx == PTITTY_MINOR_START)
- pti_tty_data->mc = pti_request_masterchannel(0);
+ pti_tty_data->mc = pti_request_masterchannel(0, NULL);
else
- pti_tty_data->mc = pti_request_masterchannel(2);
+ pti_tty_data->mc = pti_request_masterchannel(2, NULL);

if (pti_tty_data->mc == NULL) {
kfree(pti_tty_data);
@@ -563,7 +584,7 @@ static int pti_char_open(struct inode *inode, struct file *filp)
* before assigning the value to filp->private_data.
* Slightly easier to debug if this driver needs debugging.
*/
- mc = pti_request_masterchannel(0);
+ mc = pti_request_masterchannel(0, NULL);
if (mc == NULL)
return -ENOMEM;
filp->private_data = mc;
diff --git a/include/linux/pti.h b/include/linux/pti.h
index 81af667..b3ea01a 100644
--- a/include/linux/pti.h
+++ b/include/linux/pti.h
@@ -36,7 +36,8 @@ struct pti_masterchannel {

/* the following functions are defined in misc/pti.c */
void pti_writedata(struct pti_masterchannel *mc, u8 *buf, int count);
-struct pti_masterchannel *pti_request_masterchannel(u8 type);
+struct pti_masterchannel *pti_request_masterchannel(u8 type,
+ const char *thread_name);
void pti_release_masterchannel(struct pti_masterchannel *mc);

#endif /*PTI_H_*/
--
1.7.2.3


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