sh: pfc: ioremap() support

Add support for non-entity mapped PFC registers through
the use of struct resource and ioremap()/iounmap().

The PFC main data structure gets updated with a pointer
to a struct resources array that point out all register
windows used by the PFC instance. The register definitions
are kept as physical addresses but the PFC code will do
transparent conversion into virtual addresses whenever
register windows are specified using with struct resource.

To introduce as little performance penalty as possible the
virtual address of each data register is cached in memory.
The virtual address of each configuration register is however
calculated during run time. This because the configuration
is considered slow path so focus is instead put on keeping
memory foot print as small as possible.

The PFC register access  code is in this patch updated from
__raw_readN() / __raw_writeN() into ioreadN() / iowriteN().

This patch is needed to support the PFC block in r8a7779.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

Author: Magnus Damm

drivers/sh/pfc.c

@@ -19,6 +19,75 @@
 #include <linux/irq.h>
 #include <linux/bitops.h>
 #include <linux/gpio.h>
+#include <linux/slab.h>
+#include <linux/ioport.h>
+
+static void pfc_iounmap(struct pinmux_info *pip)
+{
+	int k;
+
+	for (k = 0; k < pip->num_resources; k++)
+		if (pip->window[k].virt)
+			iounmap(pip->window[k].virt);
+
+	kfree(pip->window);
+	pip->window = NULL;
+}
+
+static int pfc_ioremap(struct pinmux_info *pip)
+{
+	struct resource *res;
+	int k;
+
+	if (!pip->num_resources)
+		return 0;
+
+	pip->window = kzalloc(pip->num_resources * sizeof(*pip->window),
+			      GFP_NOWAIT);
+	if (!pip->window)
+		goto err1;
+
+	for (k = 0; k < pip->num_resources; k++) {
+		res = pip->resource + k;
+		WARN_ON(resource_type(res) != IORESOURCE_MEM);
+		pip->window[k].phys = res->start;
+		pip->window[k].size = resource_size(res);
+		pip->window[k].virt = ioremap_nocache(res->start,
+							 resource_size(res));
+		if (!pip->window[k].virt)
+			goto err2;
+	}
+
+	return 0;
+
+err2:
+	pfc_iounmap(pip);
+err1:
+	return -1;
+}
+
+static void __iomem *pfc_phys_to_virt(struct pinmux_info *pip,
+				      unsigned long address)
+{
+	struct pfc_window *window;
+	int k;
+
+	/* scan through physical windows and convert address */
+	for (k = 0; k < pip->num_resources; k++) {
+		window = pip->window + k;
+
+		if (address < window->phys)
+			continue;
+
+		if (address >= (window->phys + window->size))
+			continue;
+
+		return window->virt + (address - window->phys);
+	}
+
+	/* no windows defined, register must be 1:1 mapped virt:phys */
+	return (void __iomem *)address;
+}
 
 static int enum_in_range(pinmux_enum_t enum_id, struct pinmux_range *r)
 {
@@ -31,35 +100,35 @@ static int enum_in_range(pinmux_enum_t enum_id, struct pinmux_range *r)
 	return 1;
 }
 
-static unsigned long gpio_read_raw_reg(unsigned long reg,
+static unsigned long gpio_read_raw_reg(void __iomem *mapped_reg,
 				       unsigned long reg_width)
 {
 	switch (reg_width) {
 	case 8:
-		return __raw_readb(reg);
+		return ioread8(mapped_reg);
 	case 16:
-		return __raw_readw(reg);
+		return ioread16(mapped_reg);
 	case 32:
-		return __raw_readl(reg);
+		return ioread32(mapped_reg);
 	}
 
 	BUG();
 	return 0;
 }
 
-static void gpio_write_raw_reg(unsigned long reg,
+static void gpio_write_raw_reg(void __iomem *mapped_reg,
 			       unsigned long reg_width,
 			       unsigned long data)
 {
 	switch (reg_width) {
 	case 8:
-		__raw_writeb(data, reg);
+		iowrite8(data, mapped_reg);
 		return;
 	case 16:
-		__raw_writew(data, reg);
+		iowrite16(data, mapped_reg);
 		return;
 	case 32:
-		__raw_writel(data, reg);
+		iowrite32(data, mapped_reg);
 		return;
 	}
 
@@ -82,11 +151,12 @@ static void gpio_write_bit(struct pinmux_data_reg *dr,
 	else
 		clear_bit(pos, &dr->reg_shadow);
 
-	gpio_write_raw_reg(dr->reg, dr->reg_width, dr->reg_shadow);
+	gpio_write_raw_reg(dr->mapped_reg, dr->reg_width, dr->reg_shadow);
 }
 
-static int gpio_read_reg(unsigned long reg, unsigned long reg_width,
-			 unsigned long field_width, unsigned long in_pos)
+static int gpio_read_reg(void __iomem *mapped_reg, unsigned long reg_width,
+			 unsigned long field_width, unsigned long in_pos,
+			 unsigned long reg)
 {
 	unsigned long data, mask, pos;
 
@@ -98,13 +168,13 @@ static int gpio_read_reg(unsigned long reg, unsigned long reg_width,
 		 "r_width = %ld, f_width = %ld\n",
 		 reg, pos, reg_width, field_width);
 
-	data = gpio_read_raw_reg(reg, reg_width);
+	data = gpio_read_raw_reg(mapped_reg, reg_width);
 	return (data >> pos) & mask;
 }
 
-static void gpio_write_reg(unsigned long reg, unsigned long reg_width,
+static void gpio_write_reg(void __iomem *mapped_reg, unsigned long reg_width,
 			   unsigned long field_width, unsigned long in_pos,
-			   unsigned long value)
+			   unsigned long value, unsigned long reg)
 {
 	unsigned long mask, pos;
 
@@ -120,13 +190,13 @@ static void gpio_write_reg(unsigned long reg, unsigned long reg_width,
 
 	switch (reg_width) {
 	case 8:
-		__raw_writeb((__raw_readb(reg) & mask) | value, reg);
+		iowrite8((ioread8(mapped_reg) & mask) | value, mapped_reg);
 		break;
 	case 16:
-		__raw_writew((__raw_readw(reg) & mask) | value, reg);
+		iowrite16((ioread16(mapped_reg) & mask) | value, mapped_reg);
 		break;
 	case 32:
-		__raw_writel((__raw_readl(reg) & mask) | value, reg);
+		iowrite32((ioread32(mapped_reg) & mask) | value, mapped_reg);
 		break;
 	}
 }
@@ -147,6 +217,8 @@ static int setup_data_reg(struct pinmux_info *gpioc, unsigned gpio)
 		if (!data_reg->reg_width)
 			break;
 
+		data_reg->mapped_reg = pfc_phys_to_virt(gpioc, data_reg->reg);
+
 		for (n = 0; n < data_reg->reg_width; n++) {
 			if (data_reg->enum_ids[n] == gpiop->enum_id) {
 				gpiop->flags &= ~PINMUX_FLAG_DREG;
@@ -179,7 +251,8 @@ static void setup_data_regs(struct pinmux_info *gpioc)
 		if (!drp->reg_width)
 			break;
 
-		drp->reg_shadow = gpio_read_raw_reg(drp->reg, drp->reg_width);
+		drp->reg_shadow = gpio_read_raw_reg(drp->mapped_reg,
+						    drp->reg_width);
 		k++;
 	}
 }
@@ -266,26 +339,33 @@ static void write_config_reg(struct pinmux_info *gpioc,
 			     int index)
 {
 	unsigned long ncomb, pos, value;
+	void __iomem *mapped_reg;
 
 	ncomb = 1 << crp->field_width;
 	pos = index / ncomb;
 	value = index % ncomb;
 
-	gpio_write_reg(crp->reg, crp->reg_width, crp->field_width, pos, value);
+	mapped_reg = pfc_phys_to_virt(gpioc, crp->reg);
+
+	gpio_write_reg(mapped_reg, crp->reg_width, crp->field_width,
+		       pos, value, crp->reg);
 }
 
 static int check_config_reg(struct pinmux_info *gpioc,
 			    struct pinmux_cfg_reg *crp,
 			    int index)
 {
 	unsigned long ncomb, pos, value;
+	void __iomem *mapped_reg;
 
 	ncomb = 1 << crp->field_width;
 	pos = index / ncomb;
 	value = index % ncomb;
 
-	if (gpio_read_reg(crp->reg, crp->reg_width,
-			  crp->field_width, pos) == value)
+	mapped_reg = pfc_phys_to_virt(gpioc, crp->reg);
+
+	if (gpio_read_reg(mapped_reg, crp->reg_width,
+			  crp->field_width, pos, crp->reg) == value)
 		return 0;
 
 	return -1;
@@ -564,7 +644,7 @@ static int sh_gpio_get_value(struct pinmux_info *gpioc, unsigned gpio)
 	if (!gpioc || get_data_reg(gpioc, gpio, &dr, &bit) != 0)
 		return -EINVAL;
 
-	return gpio_read_reg(dr->reg, dr->reg_width, 1, bit);
+	return gpio_read_reg(dr->mapped_reg, dr->reg_width, 1, bit, dr->reg);
 }
 
 static int sh_gpio_get(struct gpio_chip *chip, unsigned offset)
@@ -606,10 +686,15 @@ static int sh_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
 int register_pinmux(struct pinmux_info *pip)
 {
 	struct gpio_chip *chip = &pip->chip;
+	int ret;
 
 	pr_info("%s handling gpio %d -> %d\n",
 		pip->name, pip->first_gpio, pip->last_gpio);
 
+	ret = pfc_ioremap(pip);
+	if (ret < 0)
+		return ret;
+
 	setup_data_regs(pip);
 
 	chip->request = sh_gpio_request;
@@ -627,12 +712,16 @@ int register_pinmux(struct pinmux_info *pip)
 	chip->base = pip->first_gpio;
 	chip->ngpio = (pip->last_gpio - pip->first_gpio) + 1;
 
-	return gpiochip_add(chip);
+	ret = gpiochip_add(chip);
+	if (ret < 0)
+		pfc_iounmap(pip);
+
+	return ret;
 }
 
 int unregister_pinmux(struct pinmux_info *pip)
 {
 	pr_info("%s deregistering\n", pip->name);
-
+	pfc_iounmap(pip);
 	return gpiochip_remove(&pip->chip);
 }

include/linux/sh_pfc.h

@@ -55,6 +55,7 @@ struct pinmux_cfg_reg {
 struct pinmux_data_reg {
 	unsigned long reg, reg_width, reg_shadow;
 	pinmux_enum_t *enum_ids;
+	void __iomem *mapped_reg;
 };
 
 #define PINMUX_DATA_REG(name, r, r_width) \
@@ -75,6 +76,12 @@ struct pinmux_range {
 	pinmux_enum_t force;
 };
 
+struct pfc_window {
+	phys_addr_t phys;
+	void __iomem *virt;
+	unsigned long size;
+};
+
 struct pinmux_info {
 	char *name;
 	pinmux_enum_t reserved_id;
@@ -98,6 +105,10 @@ struct pinmux_info {
 	struct pinmux_irq *gpio_irq;
 	unsigned int gpio_irq_size;
 
+	struct resource *resource;
+	unsigned int num_resources;
+	struct pfc_window *window;
+
 	struct gpio_chip chip;
 };