[PATCH 6/6] platform/x86: acerhdf: restructure to allow large BIOS table be __initconst

From: Paul Gortmaker
Date: Thu Sep 20 2018 - 21:46:12 EST


There is a table of Vendor/Model/Version {control data} in this driver,
but outside of the initial probe, the V/M/V is never used again, and
neither are any of the entries for platforms other than the one which
matches the running target.

By simply storing the {control data} for the matched platform, we can
mark the large table __initconst, which reduces the loaded driver size
by 20 percent.

Before:
root@gw:~/git/linux-head# lsmod
Module Size Used by
acerhdf 20480 0
root@gw:~/git/linux-head#

After:
root@gw:~/git/linux-head# lsmod
Module Size Used by
acerhdf 16384 0
root@gw:~/git/linux-head#

Cc: Peter Feuerer <peter@xxxxxxxx>
Cc: Darren Hart <dvhart@xxxxxxxxxxxxx>
Cc: Andy Shevchenko <andy@xxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
drivers/platform/x86/acerhdf.c | 41 ++++++++++++++++++++++++++++-------------
1 file changed, 28 insertions(+), 13 deletions(-)

diff --git a/drivers/platform/x86/acerhdf.c b/drivers/platform/x86/acerhdf.c
index 5f579fcde315..505224225378 100644
--- a/drivers/platform/x86/acerhdf.c
+++ b/drivers/platform/x86/acerhdf.c
@@ -133,7 +133,7 @@ static const struct manualcmd mcmd = {
.moff = 0xff,
};

-/* BIOS settings */
+/* BIOS settings - only used during probe */
struct bios_settings {
const char *vendor;
const char *product;
@@ -144,8 +144,18 @@ struct bios_settings {
int mcmd_enable;
};

+/* This could be a daughter struct in the above, but not worth the redirect */
+struct ctrl_settings {
+ u8 fanreg;
+ u8 tempreg;
+ struct fancmd cmd;
+ int mcmd_enable;
+};
+
+static struct ctrl_settings ctrl_cfg __read_mostly;
+
/* Register addresses and values for different BIOS versions */
-static const struct bios_settings bios_tbl[] = {
+static const struct bios_settings bios_tbl[] __initconst = {
/* AOA110 */
{"Acer", "AOA110", "v0.3109", 0x55, 0x58, {0x1f, 0x00}, 0},
{"Acer", "AOA110", "v0.3114", 0x55, 0x58, {0x1f, 0x00}, 0},
@@ -260,8 +270,6 @@ static const struct bios_settings bios_tbl[] = {
{"", "", "", 0, 0, {0, 0}, 0}
};

-static const struct bios_settings *bios_cfg __read_mostly;
-
/*
* this struct is used to instruct thermal layer to use bang_bang instead of
* default governor for acerhdf
@@ -274,7 +282,7 @@ static int acerhdf_get_temp(int *temp)
{
u8 read_temp;

- if (ec_read(bios_cfg->tempreg, &read_temp))
+ if (ec_read(ctrl_cfg.tempreg, &read_temp))
return -EINVAL;

*temp = read_temp * 1000;
@@ -286,10 +294,10 @@ static int acerhdf_get_fanstate(int *state)
{
u8 fan;

- if (ec_read(bios_cfg->fanreg, &fan))
+ if (ec_read(ctrl_cfg.fanreg, &fan))
return -EINVAL;

- if (fan != bios_cfg->cmd.cmd_off)
+ if (fan != ctrl_cfg.cmd.cmd_off)
*state = ACERHDF_FAN_AUTO;
else
*state = ACERHDF_FAN_OFF;
@@ -310,13 +318,13 @@ static void acerhdf_change_fanstate(int state)
state = ACERHDF_FAN_AUTO;
}

- cmd = (state == ACERHDF_FAN_OFF) ? bios_cfg->cmd.cmd_off
- : bios_cfg->cmd.cmd_auto;
+ cmd = (state == ACERHDF_FAN_OFF) ? ctrl_cfg.cmd.cmd_off
+ : ctrl_cfg.cmd.cmd_auto;
fanstate = state;

- ec_write(bios_cfg->fanreg, cmd);
+ ec_write(ctrl_cfg.fanreg, cmd);

- if (bios_cfg->mcmd_enable && state == ACERHDF_FAN_OFF) {
+ if (ctrl_cfg.mcmd_enable && state == ACERHDF_FAN_OFF) {
if (verbose)
pr_notice("turning off fan manually\n");
ec_write(mcmd.mreg, mcmd.moff);
@@ -623,6 +631,7 @@ static int __init acerhdf_check_hardware(void)
{
char const *vendor, *version, *product;
const struct bios_settings *bt = NULL;
+ int found = 0;

/* get BIOS data */
vendor = dmi_get_system_info(DMI_SYS_VENDOR);
@@ -672,17 +681,23 @@ static int __init acerhdf_check_hardware(void)
if (str_starts_with(vendor, bt->vendor) &&
str_starts_with(product, bt->product) &&
str_starts_with(version, bt->version)) {
- bios_cfg = bt;
+ found = 1;
break;
}
}

- if (!bios_cfg) {
+ if (!found) {
pr_err("unknown (unsupported) BIOS version %s/%s/%s, please report, aborting!\n",
vendor, product, version);
return -EINVAL;
}

+ /* Copy control settings from BIOS table before we free it. */
+ ctrl_cfg.fanreg = bt->fanreg;
+ ctrl_cfg.tempreg = bt->tempreg;
+ memcpy(&ctrl_cfg.cmd, &bt->cmd, sizeof(struct fancmd));
+ ctrl_cfg.mcmd_enable = bt->mcmd_enable;
+
/*
* if started with kernel mode off, prevent the kernel from switching
* off the fan
--
2.15.0