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crossystem: handle BayTrail gpios

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BayTrail systems have 3 banks of gpios. Therefore,
the Linux kernel exposes these 3 banks as 3 gpiochip
entries. The kernel driver expects the 3 banks to be
exposed with specific UIDs associated with a specific
banks. ChromeOS firmware maps gpios within a given
bank using the bank's MMIO offset. In summary:

Bank Type | UID | Offset
----------+-----+-------
 SCORE    |  1  | 0x0000
 NCORE    |  2  | 0x1000
 SUS      |  3  | 0x2000

BUG=chrome-os-partner:24408
BUG=chrome-os-partner:24324
BRANCH=None
TEST=Built. 'crossystem wpsw_cur' works correctly.

Change-Id: I251f86285ce9733f7ca90ed1ebef536f4fe5c07c
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/179513
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
This commit is contained in:
Aaron Durbin
2013-12-10 16:05:30 -08:00
committed by chrome-internal-fetch
parent 31912b61a7
commit 1aa59b0ea5
1 changed files with 54 additions and 0 deletions
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54
host/arch/x86/lib/crossystem_arch.c
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@@ -519,6 +519,59 @@ static int FindGpioChipOffset(int *gpio_num, int *offset) {
return (1 == match);
}
/* BayTrail has 3 sets of GPIO banks. It is expected the firmware exposes
* each bank of gpios using a UID in ACPI. Furthermore the gpio number exposed
* is relative to the bank. e.g. gpio 6 in the bank specified by UID 3 would
* be encoded as 0x2006.
* UID | Bank Offset
* ----+------------
* 1 | 0x0000
* 2 | 0x1000
* 3 | 0x2000
*/
static int BayTrailFindGpioChipOffset(int *gpio_num, int *offset) {
DIR *dir;
struct dirent *ent;
int expected_uid;
int match = 0;
/* Obtain relative GPIO number. */
if (*gpio_num >= 0x2000) {
*gpio_num -= 0x2000;
expected_uid = 3;
} else if (*gpio_num >= 0x1000) {
*gpio_num -= 0x1000;
expected_uid = 2;
} else if (*gpio_num >= 0x0000) {
*gpio_num -= 0x0000;
expected_uid = 1;
} else {
return 0;
}
dir = opendir(GPIO_BASE_PATH);
if (!dir) {
return 0;
}
while(0 != (ent = readdir(dir))) {
/* For every gpiochip entry determine uid. */
if (1 == sscanf(ent->d_name, "gpiochip%d", offset)) {
char uid_file[128];
snprintf(uid_file, sizeof(uid_file),
"%s/gpiochip%d/device/firmware_node/uid", GPIO_BASE_PATH,
*offset);
if (expected_uid == ReadFileInt(uid_file)) {
match++;
break;
}
}
}
closedir(dir);
return (1 == match);
}
struct GpioChipset {
const char *name;
@@ -530,6 +583,7 @@ static const struct GpioChipset chipsets_supported[] = {
{ "CougarPoint", FindGpioChipOffset },
{ "PantherPoint", FindGpioChipOffset },
{ "LynxPoint", FindGpioChipOffset },
{ "BayTrail", BayTrailFindGpioChipOffset },
{ NULL },
};