sh: make gpio_get/set_value() O(1)
This patch modifies the table based SuperH gpio implementation to
make use of direct table lookups. With this change the functions
gpio_get_value() and gpio_set_value() are O(1).
Tested on Migo-R using bitbanging mmc. Performance is improved from
11 KBytes/s to 26 Kbytes/s.
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/kernel/gpio.c b/arch/sh/kernel/gpio.c
index d371653..fe92ba1 100644
--- a/arch/sh/kernel/gpio.c
+++ b/arch/sh/kernel/gpio.c
@@ -95,14 +95,13 @@
return 0;
}
-static int get_data_reg(struct pinmux_info *gpioc, unsigned gpio,
- struct pinmux_data_reg **drp, int *bitp)
+static int setup_data_reg(struct pinmux_info *gpioc, unsigned gpio)
{
- pinmux_enum_t enum_id = gpioc->gpios[gpio].enum_id;
+ struct pinmux_gpio *gpiop = &gpioc->gpios[gpio];
struct pinmux_data_reg *data_reg;
int k, n;
- if (!enum_in_range(enum_id, &gpioc->data))
+ if (!enum_in_range(gpiop->enum_id, &gpioc->data))
return -1;
k = 0;
@@ -113,19 +112,38 @@
break;
for (n = 0; n < data_reg->reg_width; n++) {
- if (data_reg->enum_ids[n] == enum_id) {
- *drp = data_reg;
- *bitp = n;
+ if (data_reg->enum_ids[n] == gpiop->enum_id) {
+ gpiop->flags &= ~PINMUX_FLAG_DREG;
+ gpiop->flags |= (k << PINMUX_FLAG_DREG_SHIFT);
+ gpiop->flags &= ~PINMUX_FLAG_DBIT;
+ gpiop->flags |= (n << PINMUX_FLAG_DBIT_SHIFT);
return 0;
-
}
}
k++;
}
+ BUG();
+
return -1;
}
+static int get_data_reg(struct pinmux_info *gpioc, unsigned gpio,
+ struct pinmux_data_reg **drp, int *bitp)
+{
+ struct pinmux_gpio *gpiop = &gpioc->gpios[gpio];
+ int k, n;
+
+ if (!enum_in_range(gpiop->enum_id, &gpioc->data))
+ return -1;
+
+ k = (gpiop->flags & PINMUX_FLAG_DREG) >> PINMUX_FLAG_DREG_SHIFT;
+ n = (gpiop->flags & PINMUX_FLAG_DBIT) >> PINMUX_FLAG_DBIT_SHIFT;
+ *drp = gpioc->data_regs + k;
+ *bitp = n;
+ return 0;
+}
+
static int get_config_reg(struct pinmux_info *gpioc, pinmux_enum_t enum_id,
struct pinmux_cfg_reg **crp, int *indexp,
unsigned long **cntp)
@@ -341,7 +359,8 @@
BUG();
}
- gpioc->gpios[gpio].flags = pinmux_type;
+ gpioc->gpios[gpio].flags &= ~PINMUX_FLAG_TYPE;
+ gpioc->gpios[gpio].flags |= pinmux_type;
ret = 0;
err_unlock:
@@ -364,7 +383,8 @@
pinmux_type = gpioc->gpios[gpio].flags & PINMUX_FLAG_TYPE;
pinmux_config_gpio(gpioc, gpio, pinmux_type, GPIO_CFG_FREE);
- gpioc->gpios[gpio].flags = PINMUX_TYPE_NONE;
+ gpioc->gpios[gpio].flags &= ~PINMUX_FLAG_TYPE;
+ gpioc->gpios[gpio].flags |= PINMUX_TYPE_NONE;
spin_unlock_irqrestore(&gpio_lock, flags);
}
@@ -401,7 +421,8 @@
GPIO_CFG_REQ) != 0)
BUG();
- gpioc->gpios[gpio].flags = new_pinmux_type;
+ gpioc->gpios[gpio].flags &= ~PINMUX_FLAG_TYPE;
+ gpioc->gpios[gpio].flags |= new_pinmux_type;
ret = 0;
err_out:
@@ -494,9 +515,14 @@
int register_pinmux(struct pinmux_info *pip)
{
+ int k;
+
registered_gpio = pip;
pr_info("pinmux: %s handling gpio %d -> %d\n",
pip->name, pip->first_gpio, pip->last_gpio);
+ for (k = pip->first_gpio; k <= pip->last_gpio; k++)
+ setup_data_reg(pip, k);
+
return 0;
}