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Commit 18801be7 authored by Magnus Damm's avatar Magnus Damm Committed by Paul Mundt
Browse files

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: default avatarMagnus Damm <damm@igel.co.jp>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent 53760710

arch/sh/include/asm/gpio.h

+6 −1
Original line number Diff line number Diff line
@@ -20,7 +20,7 @@ 
#endif



typedef unsigned short pinmux_enum_t;

typedef unsigned char pinmux_flag_t;

typedef unsigned short pinmux_flag_t;



#define PINMUX_TYPE_NONE            0

#define PINMUX_TYPE_FUNCTION        1
@@ -34,6 +34,11 @@ typedef unsigned char pinmux_flag_t; 
#define PINMUX_FLAG_WANT_PULLUP     (1 << 3)

#define PINMUX_FLAG_WANT_PULLDOWN   (1 << 4)



#define PINMUX_FLAG_DBIT_SHIFT      5

#define PINMUX_FLAG_DBIT            (0x1f << PINMUX_FLAG_DBIT_SHIFT)

#define PINMUX_FLAG_DREG_SHIFT      10

#define PINMUX_FLAG_DREG            (0x3f << PINMUX_FLAG_DREG_SHIFT)



struct pinmux_gpio {

	pinmux_enum_t enum_id;

	pinmux_flag_t flags;

arch/sh/kernel/gpio.c

+37 −11
Original line number Diff line number Diff line
@@ -95,14 +95,13 @@ static int read_write_reg(unsigned long reg, unsigned long reg_width, 
	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 @@ static int get_data_reg(struct pinmux_info *gpioc, unsigned gpio, 
			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 @@ int __gpio_request(unsigned gpio) 
			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 @@ void gpio_free(unsigned gpio) 


	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 @@ static int pinmux_direction(struct pinmux_info *gpioc, 
			       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 @@ EXPORT_SYMBOL(gpio_set_value); 


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;

}