[v6,3/7] gpio: aspeed: Create llops to handle hardware access

Commit Message

Billy Tsai Sept. 27, 2024, 11:17 a.m. UTC

Add low-level operations (llops) to abstract the register access for GPIO
registers and the coprocessor request/release. With this abstraction
layer, the driver can separate the hardware and software logic, making it
easier to extend the driver to support different hardware register
layouts.

Signed-off-by: Billy Tsai <[e-mail]>
---
 drivers/gpio/gpio-aspeed.c | 447 +++++++++++++++++++------------------
 1 file changed, 235 insertions(+), 212 deletions(-)

Comments

Andrew Jeffery Sept. 30, 2024, 4 a.m. UTC | #1

On Fri, 2024-09-27 at 19:17 +0800, Billy Tsai wrote:
> 
> +
> +static const struct aspeed_gpio_llops aspeed_g4_llops = {
> +	.copro_request = aspeed_g4_copro_request,
> +	.copro_release = aspeed_g4_copro_release,
> +	.reg_bit_set = aspeed_g4_reg_bit_set,
> +	.reg_bit_get = aspeed_g4_reg_bit_get,
> +	.reg_bank_get = aspeed_g4_reg_bank_get,
> +	.privilege_ctrl = aspeed_g4_privilege_ctrl,
> +	.privilege_init = aspeed_g4_privilege_init,
> +};

A brief nitpick as I have another comment below - can you order these
assignments in the same order as the member declarations in the struct
(you re-ordered that in v6)?

> @@ -1191,6 +1214,10 @@ static int __init aspeed_gpio_probe(struct platform_device *pdev)
>  
>  	gpio->config = gpio_id->data;
>  
> +	if (!gpio->config->llops->reg_bit_set || !gpio->config->llops->reg_bit_get ||
> +	    !gpio->config->llops->reg_bank_get)
> +		return -EINVAL;
> +

I think the patch is largely in good shape. I've given it some light
testing. The only concern I have is this is introducing another
resource cleanup bug right now, but that's only because you've ordered
the devm_clk_get_enabled() patch as the last in the series. If you
order it before this patch then the direct return above should no-
longer be a concern.

Andrew

Patch

diff --git a/drivers/gpio/gpio-aspeed.c b/drivers/gpio/gpio-aspeed.c
index d20e15b2079d..3ed58289a4a8 100644
--- a/drivers/gpio/gpio-aspeed.c
+++ b/drivers/gpio/gpio-aspeed.c
@@ -39,6 +39,10 @@  struct aspeed_bank_props {
 struct aspeed_gpio_config {
 	unsigned int nr_gpios;
 	const struct aspeed_bank_props *props;
+	const struct aspeed_gpio_llops *llops;
+	const int *debounce_timers_array;
+	int debounce_timers_num;
+	bool require_dcache;
 };
 
 /*
@@ -178,6 +182,19 @@  enum aspeed_gpio_reg {
 	reg_cmdsrc1,
 };
 
+struct aspeed_gpio_llops {
+	void (*reg_bit_set)(struct aspeed_gpio *gpio, unsigned int offset,
+			    const enum aspeed_gpio_reg reg, bool val);
+	bool (*reg_bit_get)(struct aspeed_gpio *gpio, unsigned int offset,
+			    const enum aspeed_gpio_reg reg);
+	int (*reg_bank_get)(struct aspeed_gpio *gpio, unsigned int offset,
+			    const enum aspeed_gpio_reg reg);
+	void (*privilege_ctrl)(struct aspeed_gpio *gpio, unsigned int offset, int owner);
+	void (*privilege_init)(struct aspeed_gpio *gpio);
+	bool (*copro_request)(struct aspeed_gpio *gpio, unsigned int offset);
+	void (*copro_release)(struct aspeed_gpio *gpio, unsigned int offset);
+};
+
 #define GPIO_VAL_VALUE	0x00
 #define GPIO_VAL_DIR	0x04
 
@@ -198,9 +215,9 @@  enum aspeed_gpio_reg {
 #define  GPIO_CMDSRC_RESERVED		3
 
 /* This will be resolved at compile time */
-static inline void __iomem *bank_reg(struct aspeed_gpio *gpio,
-				     const struct aspeed_gpio_bank *bank,
-				     const enum aspeed_gpio_reg reg)
+static void __iomem *aspeed_gpio_g4_bank_reg(struct aspeed_gpio *gpio,
+					     const struct aspeed_gpio_bank *bank,
+					     const enum aspeed_gpio_reg reg)
 {
 	switch (reg) {
 	case reg_val:
@@ -237,10 +254,6 @@  static inline void __iomem *bank_reg(struct aspeed_gpio *gpio,
 #define GPIO_OFFSET(x)	((x) & 0x1f)
 #define GPIO_BIT(x)	BIT(GPIO_OFFSET(x))
 
-#define _GPIO_SET_DEBOUNCE(t, o, i) ((!!((t) & BIT(i))) << GPIO_OFFSET(o))
-#define GPIO_SET_DEBOUNCE1(t, o) _GPIO_SET_DEBOUNCE(t, o, 1)
-#define GPIO_SET_DEBOUNCE2(t, o) _GPIO_SET_DEBOUNCE(t, o, 0)
-
 static const struct aspeed_gpio_bank *to_bank(unsigned int offset)
 {
 	unsigned int bank = GPIO_BANK(offset);
@@ -296,107 +309,48 @@  static inline bool have_output(struct aspeed_gpio *gpio, unsigned int offset)
 }
 
 static void aspeed_gpio_change_cmd_source(struct aspeed_gpio *gpio,
-					  const struct aspeed_gpio_bank *bank,
-					  int bindex, int cmdsrc)
+					  unsigned int offset,
+					  int cmdsrc)
 {
-	void __iomem *c0 = bank_reg(gpio, bank, reg_cmdsrc0);
-	void __iomem *c1 = bank_reg(gpio, bank, reg_cmdsrc1);
-	u32 bit, reg;
-
-	/*
-	 * Each register controls 4 banks, so take the bottom 2
-	 * bits of the bank index, and use them to select the
-	 * right control bit (0, 8, 16 or 24).
-	 */
-	bit = BIT((bindex & 3) << 3);
-
-	/* Source 1 first to avoid illegal 11 combination */
-	reg = ioread32(c1);
-	if (cmdsrc & 2)
-		reg |= bit;
-	else
-		reg &= ~bit;
-	iowrite32(reg, c1);
-
-	/* Then Source 0 */
-	reg = ioread32(c0);
-	if (cmdsrc & 1)
-		reg |= bit;
-	else
-		reg &= ~bit;
-	iowrite32(reg, c0);
+	if (gpio->config->llops->privilege_ctrl)
+		gpio->config->llops->privilege_ctrl(gpio, offset, cmdsrc);
 }
 
 static bool aspeed_gpio_copro_request(struct aspeed_gpio *gpio,
 				      unsigned int offset)
 {
-	const struct aspeed_gpio_bank *bank = to_bank(offset);
-
-	if (!copro_ops || !gpio->cf_copro_bankmap)
-		return false;
-	if (!gpio->cf_copro_bankmap[offset >> 3])
-		return false;
-	if (!copro_ops->request_access)
-		return false;
-
-	/* Pause the coprocessor */
-	copro_ops->request_access(copro_data);
-
-	/* Change command source back to ARM */
-	aspeed_gpio_change_cmd_source(gpio, bank, offset >> 3, GPIO_CMDSRC_ARM);
-
-	/* Update cache */
-	gpio->dcache[GPIO_BANK(offset)] = ioread32(bank_reg(gpio, bank, reg_rdata));
+	if (gpio->config->llops->copro_request)
+		return gpio->config->llops->copro_request(gpio, offset);
 
-	return true;
+	return false;
 }
 
 static void aspeed_gpio_copro_release(struct aspeed_gpio *gpio,
 				      unsigned int offset)
 {
-	const struct aspeed_gpio_bank *bank = to_bank(offset);
-
-	if (!copro_ops || !gpio->cf_copro_bankmap)
-		return;
-	if (!gpio->cf_copro_bankmap[offset >> 3])
-		return;
-	if (!copro_ops->release_access)
-		return;
-
-	/* Change command source back to ColdFire */
-	aspeed_gpio_change_cmd_source(gpio, bank, offset >> 3,
-				      GPIO_CMDSRC_COLDFIRE);
+	if (gpio->config->llops->copro_release)
+		gpio->config->llops->copro_release(gpio, offset);
+}
 
-	/* Restart the coprocessor */
-	copro_ops->release_access(copro_data);
+static bool aspeed_gpio_support_copro(struct aspeed_gpio *gpio)
+{
+	return gpio->config->llops->copro_request && gpio->config->llops->copro_release &&
+	       gpio->config->llops->privilege_ctrl && gpio->config->llops->privilege_init;
 }
 
 static int aspeed_gpio_get(struct gpio_chip *gc, unsigned int offset)
 {
 	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
-	const struct aspeed_gpio_bank *bank = to_bank(offset);
 
-	return !!(ioread32(bank_reg(gpio, bank, reg_val)) & GPIO_BIT(offset));
+	return gpio->config->llops->reg_bit_get(gpio, offset, reg_val);
 }
 
 static void __aspeed_gpio_set(struct gpio_chip *gc, unsigned int offset,
 			      int val)
 {
 	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
-	const struct aspeed_gpio_bank *bank = to_bank(offset);
-	void __iomem *addr;
-	u32 reg;
-
-	addr = bank_reg(gpio, bank, reg_val);
-	reg = gpio->dcache[GPIO_BANK(offset)];
-
-	if (val)
-		reg |= GPIO_BIT(offset);
-	else
-		reg &= ~GPIO_BIT(offset);
-	gpio->dcache[GPIO_BANK(offset)] = reg;
 
-	iowrite32(reg, addr);
+	gpio->config->llops->reg_bit_set(gpio, offset, reg_val, val);
 }
 
 static void aspeed_gpio_set(struct gpio_chip *gc, unsigned int offset,
@@ -404,7 +358,7 @@  static void aspeed_gpio_set(struct gpio_chip *gc, unsigned int offset,
 {
 	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
 	unsigned long flags;
-	bool copro;
+	bool copro = false;
 
 	raw_spin_lock_irqsave(&gpio->lock, flags);
 	copro = aspeed_gpio_copro_request(gpio, offset);
@@ -419,22 +373,16 @@  static void aspeed_gpio_set(struct gpio_chip *gc, unsigned int offset,
 static int aspeed_gpio_dir_in(struct gpio_chip *gc, unsigned int offset)
 {
 	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
-	const struct aspeed_gpio_bank *bank = to_bank(offset);
-	void __iomem *addr = bank_reg(gpio, bank, reg_dir);
 	unsigned long flags;
-	bool copro;
-	u32 reg;
+	bool copro = false;
 
 	if (!have_input(gpio, offset))
 		return -ENOTSUPP;
 
 	raw_spin_lock_irqsave(&gpio->lock, flags);
 
-	reg = ioread32(addr);
-	reg &= ~GPIO_BIT(offset);
-
 	copro = aspeed_gpio_copro_request(gpio, offset);
-	iowrite32(reg, addr);
+	gpio->config->llops->reg_bit_set(gpio, offset, reg_dir, 0);
 	if (copro)
 		aspeed_gpio_copro_release(gpio, offset);
 
@@ -447,23 +395,17 @@  static int aspeed_gpio_dir_out(struct gpio_chip *gc,
 			       unsigned int offset, int val)
 {
 	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
-	const struct aspeed_gpio_bank *bank = to_bank(offset);
-	void __iomem *addr = bank_reg(gpio, bank, reg_dir);
 	unsigned long flags;
-	bool copro;
-	u32 reg;
+	bool copro = false;
 
 	if (!have_output(gpio, offset))
 		return -ENOTSUPP;
 
 	raw_spin_lock_irqsave(&gpio->lock, flags);
 
-	reg = ioread32(addr);
-	reg |= GPIO_BIT(offset);
-
 	copro = aspeed_gpio_copro_request(gpio, offset);
 	__aspeed_gpio_set(gc, offset, val);
-	iowrite32(reg, addr);
+	gpio->config->llops->reg_bit_set(gpio, offset, reg_dir, 1);
 
 	if (copro)
 		aspeed_gpio_copro_release(gpio, offset);
@@ -475,7 +417,6 @@  static int aspeed_gpio_dir_out(struct gpio_chip *gc,
 static int aspeed_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
 {
 	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
-	const struct aspeed_gpio_bank *bank = to_bank(offset);
 	unsigned long flags;
 	u32 val;
 
@@ -487,7 +428,7 @@  static int aspeed_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
 
 	raw_spin_lock_irqsave(&gpio->lock, flags);
 
-	val = ioread32(bank_reg(gpio, bank, reg_dir)) & GPIO_BIT(offset);
+	val = gpio->config->llops->reg_bit_get(gpio, offset, reg_dir);
 
 	raw_spin_unlock_irqrestore(&gpio->lock, flags);
 
@@ -496,8 +437,7 @@  static int aspeed_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
 
 static inline int irqd_to_aspeed_gpio_data(struct irq_data *d,
 					   struct aspeed_gpio **gpio,
-					   const struct aspeed_gpio_bank **bank,
-					   u32 *bit, int *offset)
+					   int *offset)
 {
 	struct aspeed_gpio *internal;
 
@@ -510,32 +450,25 @@  static inline int irqd_to_aspeed_gpio_data(struct irq_data *d,
 		return -ENOTSUPP;
 
 	*gpio = internal;
-	*bank = to_bank(*offset);
-	*bit = GPIO_BIT(*offset);
 
 	return 0;
 }
 
 static void aspeed_gpio_irq_ack(struct irq_data *d)
 {
-	const struct aspeed_gpio_bank *bank;
 	struct aspeed_gpio *gpio;
 	unsigned long flags;
-	void __iomem *status_addr;
 	int rc, offset;
-	bool copro;
-	u32 bit;
+	bool copro = false;
 
-	rc = irqd_to_aspeed_gpio_data(d, &gpio, &bank, &bit, &offset);
+	rc = irqd_to_aspeed_gpio_data(d, &gpio, &offset);
 	if (rc)
 		return;
 
-	status_addr = bank_reg(gpio, bank, reg_irq_status);
-
 	raw_spin_lock_irqsave(&gpio->lock, flags);
 	copro = aspeed_gpio_copro_request(gpio, offset);
 
-	iowrite32(bit, status_addr);
+	gpio->config->llops->reg_bit_set(gpio, offset, reg_irq_status, 1);
 
 	if (copro)
 		aspeed_gpio_copro_release(gpio, offset);
@@ -544,20 +477,15 @@  static void aspeed_gpio_irq_ack(struct irq_data *d)
 
 static void aspeed_gpio_irq_set_mask(struct irq_data *d, bool set)
 {
-	const struct aspeed_gpio_bank *bank;
 	struct aspeed_gpio *gpio;
 	unsigned long flags;
-	u32 reg, bit;
-	void __iomem *addr;
 	int rc, offset;
-	bool copro;
+	bool copro = false;
 
-	rc = irqd_to_aspeed_gpio_data(d, &gpio, &bank, &bit, &offset);
+	rc = irqd_to_aspeed_gpio_data(d, &gpio, &offset);
 	if (rc)
 		return;
 
-	addr = bank_reg(gpio, bank, reg_irq_enable);
-
 	/* Unmasking the IRQ */
 	if (set)
 		gpiochip_enable_irq(&gpio->chip, irqd_to_hwirq(d));
@@ -565,12 +493,7 @@  static void aspeed_gpio_irq_set_mask(struct irq_data *d, bool set)
 	raw_spin_lock_irqsave(&gpio->lock, flags);
 	copro = aspeed_gpio_copro_request(gpio, offset);
 
-	reg = ioread32(addr);
-	if (set)
-		reg |= bit;
-	else
-		reg &= ~bit;
-	iowrite32(reg, addr);
+	gpio->config->llops->reg_bit_set(gpio, offset, reg_irq_enable, set);
 
 	if (copro)
 		aspeed_gpio_copro_release(gpio, offset);
@@ -596,34 +519,31 @@  static int aspeed_gpio_set_type(struct irq_data *d, unsigned int type)
 	u32 type0 = 0;
 	u32 type1 = 0;
 	u32 type2 = 0;
-	u32 bit, reg;
-	const struct aspeed_gpio_bank *bank;
 	irq_flow_handler_t handler;
 	struct aspeed_gpio *gpio;
 	unsigned long flags;
-	void __iomem *addr;
 	int rc, offset;
-	bool copro;
+	bool copro = false;
 
-	rc = irqd_to_aspeed_gpio_data(d, &gpio, &bank, &bit, &offset);
+	rc = irqd_to_aspeed_gpio_data(d, &gpio, &offset);
 	if (rc)
 		return -EINVAL;
 
 	switch (type & IRQ_TYPE_SENSE_MASK) {
 	case IRQ_TYPE_EDGE_BOTH:
-		type2 |= bit;
+		type2 = 1;
 		fallthrough;
 	case IRQ_TYPE_EDGE_RISING:
-		type0 |= bit;
+		type0 = 1;
 		fallthrough;
 	case IRQ_TYPE_EDGE_FALLING:
 		handler = handle_edge_irq;
 		break;
 	case IRQ_TYPE_LEVEL_HIGH:
-		type0 |= bit;
+		type0 = 1;
 		fallthrough;
 	case IRQ_TYPE_LEVEL_LOW:
-		type1 |= bit;
+		type1 = 1;
 		handler = handle_level_irq;
 		break;
 	default:
@@ -633,20 +553,9 @@  static int aspeed_gpio_set_type(struct irq_data *d, unsigned int type)
 	raw_spin_lock_irqsave(&gpio->lock, flags);
 	copro = aspeed_gpio_copro_request(gpio, offset);
 
-	addr = bank_reg(gpio, bank, reg_irq_type0);
-	reg = ioread32(addr);
-	reg = (reg & ~bit) | type0;
-	iowrite32(reg, addr);
-
-	addr = bank_reg(gpio, bank, reg_irq_type1);
-	reg = ioread32(addr);
-	reg = (reg & ~bit) | type1;
-	iowrite32(reg, addr);
-
-	addr = bank_reg(gpio, bank, reg_irq_type2);
-	reg = ioread32(addr);
-	reg = (reg & ~bit) | type2;
-	iowrite32(reg, addr);
+	gpio->config->llops->reg_bit_set(gpio, offset, reg_irq_type0, type0);
+	gpio->config->llops->reg_bit_set(gpio, offset, reg_irq_type1, type1);
+	gpio->config->llops->reg_bit_set(gpio, offset, reg_irq_type2, type2);
 
 	if (copro)
 		aspeed_gpio_copro_release(gpio, offset);
@@ -661,7 +570,6 @@  static void aspeed_gpio_irq_handler(struct irq_desc *desc)
 {
 	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
 	struct irq_chip *ic = irq_desc_get_chip(desc);
-	struct aspeed_gpio *data = gpiochip_get_data(gc);
 	unsigned int i, p, banks;
 	unsigned long reg;
 	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
@@ -670,9 +578,7 @@  static void aspeed_gpio_irq_handler(struct irq_desc *desc)
 
 	banks = DIV_ROUND_UP(gpio->chip.ngpio, 32);
 	for (i = 0; i < banks; i++) {
-		const struct aspeed_gpio_bank *bank = &aspeed_gpio_banks[i];
-
-		reg = ioread32(bank_reg(data, bank, reg_irq_status));
+		reg = gpio->config->llops->reg_bank_get(gpio, i * 32, reg_irq_status);
 
 		for_each_set_bit(p, &reg, 32)
 			generic_handle_domain_irq(gc->irq.domain, i * 32 + p);
@@ -711,23 +617,12 @@  static int aspeed_gpio_reset_tolerance(struct gpio_chip *chip,
 {
 	struct aspeed_gpio *gpio = gpiochip_get_data(chip);
 	unsigned long flags;
-	void __iomem *treg;
-	bool copro;
-	u32 val;
-
-	treg = bank_reg(gpio, to_bank(offset), reg_tolerance);
+	bool copro = false;
 
 	raw_spin_lock_irqsave(&gpio->lock, flags);
 	copro = aspeed_gpio_copro_request(gpio, offset);
 
-	val = readl(treg);
-
-	if (enable)
-		val |= GPIO_BIT(offset);
-	else
-		val &= ~GPIO_BIT(offset);
-
-	writel(val, treg);
+	gpio->config->llops->reg_bit_set(gpio, offset, reg_tolerance, enable);
 
 	if (copro)
 		aspeed_gpio_copro_release(gpio, offset);
@@ -821,21 +716,11 @@  static inline bool timer_allocation_registered(struct aspeed_gpio *gpio,
 static void configure_timer(struct aspeed_gpio *gpio, unsigned int offset,
 		unsigned int timer)
 {
-	const struct aspeed_gpio_bank *bank = to_bank(offset);
-	const u32 mask = GPIO_BIT(offset);
-	void __iomem *addr;
-	u32 val;
-
 	/* Note: Debounce timer isn't under control of the command
 	 * source registers, so no need to sync with the coprocessor
 	 */
-	addr = bank_reg(gpio, bank, reg_debounce_sel1);
-	val = ioread32(addr);
-	iowrite32((val & ~mask) | GPIO_SET_DEBOUNCE1(timer, offset), addr);
-
-	addr = bank_reg(gpio, bank, reg_debounce_sel2);
-	val = ioread32(addr);
-	iowrite32((val & ~mask) | GPIO_SET_DEBOUNCE2(timer, offset), addr);
+	gpio->config->llops->reg_bit_set(gpio, offset, reg_debounce_sel1, !!(timer & BIT(1)));
+	gpio->config->llops->reg_bit_set(gpio, offset, reg_debounce_sel2, !!(timer & BIT(0)));
 }
 
 static int enable_debounce(struct gpio_chip *chip, unsigned int offset,
@@ -866,15 +751,15 @@  static int enable_debounce(struct gpio_chip *chip, unsigned int offset,
 	}
 
 	/* Try to find a timer already configured for the debounce period */
-	for (i = 1; i < ARRAY_SIZE(debounce_timers); i++) {
+	for (i = 1; i < gpio->config->debounce_timers_num; i++) {
 		u32 cycles;
 
-		cycles = ioread32(gpio->base + debounce_timers[i]);
+		cycles = ioread32(gpio->base + gpio->config->debounce_timers_array[i]);
 		if (requested_cycles == cycles)
 			break;
 	}
 
-	if (i == ARRAY_SIZE(debounce_timers)) {
+	if (i == gpio->config->debounce_timers_num) {
 		int j;
 
 		/*
@@ -888,8 +773,8 @@  static int enable_debounce(struct gpio_chip *chip, unsigned int offset,
 
 		if (j == ARRAY_SIZE(gpio->timer_users)) {
 			dev_warn(chip->parent,
-					"Debounce timers exhausted, cannot debounce for period %luus\n",
-					usecs);
+				 "Debounce timers exhausted, cannot debounce for period %luus\n",
+				 usecs);
 
 			rc = -EPERM;
 
@@ -905,7 +790,7 @@  static int enable_debounce(struct gpio_chip *chip, unsigned int offset,
 
 		i = j;
 
-		iowrite32(requested_cycles, gpio->base + debounce_timers[i]);
+		iowrite32(requested_cycles, gpio->base + gpio->config->debounce_timers_array[i]);
 	}
 
 	if (WARN(i == 0, "Cannot register index of disabled timer\n")) {
@@ -1008,6 +893,9 @@  int aspeed_gpio_copro_grab_gpio(struct gpio_desc *desc,
 	const struct aspeed_gpio_bank *bank = to_bank(offset);
 	unsigned long flags;
 
+	if (!aspeed_gpio_support_copro(gpio))
+		return -EOPNOTSUPP;
+
 	if (!gpio->cf_copro_bankmap)
 		gpio->cf_copro_bankmap = kzalloc(gpio->chip.ngpio >> 3, GFP_KERNEL);
 	if (!gpio->cf_copro_bankmap)
@@ -1027,7 +915,7 @@  int aspeed_gpio_copro_grab_gpio(struct gpio_desc *desc,
 
 	/* Switch command source */
 	if (gpio->cf_copro_bankmap[bindex] == 1)
-		aspeed_gpio_change_cmd_source(gpio, bank, bindex,
+		aspeed_gpio_change_cmd_source(gpio, offset,
 					      GPIO_CMDSRC_COLDFIRE);
 
 	if (vreg_offset)
@@ -1051,9 +939,11 @@  int aspeed_gpio_copro_release_gpio(struct gpio_desc *desc)
 	struct gpio_chip *chip = gpiod_to_chip(desc);
 	struct aspeed_gpio *gpio = gpiochip_get_data(chip);
 	int rc = 0, bindex, offset = gpio_chip_hwgpio(desc);
-	const struct aspeed_gpio_bank *bank = to_bank(offset);
 	unsigned long flags;
 
+	if (!aspeed_gpio_support_copro(gpio))
+		return -EOPNOTSUPP;
+
 	if (!gpio->cf_copro_bankmap)
 		return -ENXIO;
 
@@ -1072,7 +962,7 @@  int aspeed_gpio_copro_release_gpio(struct gpio_desc *desc)
 
 	/* Switch command source */
 	if (gpio->cf_copro_bankmap[bindex] == 0)
-		aspeed_gpio_change_cmd_source(gpio, bank, bindex,
+		aspeed_gpio_change_cmd_source(gpio, offset,
 					      GPIO_CMDSRC_ARM);
  bail:
 	raw_spin_unlock_irqrestore(&gpio->lock, flags);
@@ -1082,12 +972,10 @@  EXPORT_SYMBOL_GPL(aspeed_gpio_copro_release_gpio);
 
 static void aspeed_gpio_irq_print_chip(struct irq_data *d, struct seq_file *p)
 {
-	const struct aspeed_gpio_bank *bank;
 	struct aspeed_gpio *gpio;
-	u32 bit;
 	int rc, offset;
 
-	rc = irqd_to_aspeed_gpio_data(d, &gpio, &bank, &bit, &offset);
+	rc = irqd_to_aspeed_gpio_data(d, &gpio, &offset);
 	if (rc)
 		return;
 
@@ -1104,6 +992,120 @@  static const struct irq_chip aspeed_gpio_irq_chip = {
 	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
+static void aspeed_g4_reg_bit_set(struct aspeed_gpio *gpio, unsigned int offset,
+				  const enum aspeed_gpio_reg reg, bool val)
+{
+	const struct aspeed_gpio_bank *bank = to_bank(offset);
+	void __iomem *addr = aspeed_gpio_g4_bank_reg(gpio, bank, reg);
+	u32 temp;
+
+	if (reg == reg_val)
+		temp = gpio->dcache[GPIO_BANK(offset)];
+	else
+		temp = ioread32(addr);
+
+	if (val)
+		temp |= GPIO_BIT(offset);
+	else
+		temp &= ~GPIO_BIT(offset);
+
+	if (reg == reg_val)
+		gpio->dcache[GPIO_BANK(offset)] = temp;
+	iowrite32(temp, addr);
+}
+
+static bool aspeed_g4_reg_bit_get(struct aspeed_gpio *gpio, unsigned int offset,
+				  const enum aspeed_gpio_reg reg)
+{
+	const struct aspeed_gpio_bank *bank = to_bank(offset);
+	void __iomem *addr = aspeed_gpio_g4_bank_reg(gpio, bank, reg);
+
+	return !!(ioread32(addr) & GPIO_BIT(offset));
+}
+
+static int aspeed_g4_reg_bank_get(struct aspeed_gpio *gpio, unsigned int offset,
+				  const enum aspeed_gpio_reg reg)
+{
+	const struct aspeed_gpio_bank *bank = to_bank(offset);
+	void __iomem *addr = aspeed_gpio_g4_bank_reg(gpio, bank, reg);
+
+	if (reg == reg_rdata || reg == reg_irq_status)
+		return ioread32(addr);
+	else
+		return -EOPNOTSUPP;
+}
+
+static void aspeed_g4_privilege_ctrl(struct aspeed_gpio *gpio, unsigned int offset, int cmdsrc)
+{
+	/*
+	 * The command source register is only valid in bits 0, 8, 16, and 24, so we use
+	 * (offset & ~(0x7)) to ensure that reg_bits_set always targets a valid bit.
+	 */
+	/* Source 1 first to avoid illegal 11 combination */
+	aspeed_g4_reg_bit_set(gpio, offset & ~(0x7), reg_cmdsrc1, !!(cmdsrc & BIT(1)));
+	/* Then Source 0 */
+	aspeed_g4_reg_bit_set(gpio, offset & ~(0x7), reg_cmdsrc0, !!(cmdsrc & BIT(0)));
+}
+
+static void aspeed_g4_privilege_init(struct aspeed_gpio *gpio)
+{
+	u32 i;
+
+	/* Switch all command sources to the ARM by default */
+	for (i = 0; i < DIV_ROUND_UP(gpio->chip.ngpio, 32); i++) {
+		aspeed_g4_privilege_ctrl(gpio, (i << 5) + 0, GPIO_CMDSRC_ARM);
+		aspeed_g4_privilege_ctrl(gpio, (i << 5) + 8, GPIO_CMDSRC_ARM);
+		aspeed_g4_privilege_ctrl(gpio, (i << 5) + 16, GPIO_CMDSRC_ARM);
+		aspeed_g4_privilege_ctrl(gpio, (i << 5) + 24, GPIO_CMDSRC_ARM);
+	}
+}
+
+static bool aspeed_g4_copro_request(struct aspeed_gpio *gpio, unsigned int offset)
+{
+	if (!copro_ops || !gpio->cf_copro_bankmap)
+		return false;
+	if (!gpio->cf_copro_bankmap[offset >> 3])
+		return false;
+	if (!copro_ops->request_access)
+		return false;
+
+	/* Pause the coprocessor */
+	copro_ops->request_access(copro_data);
+
+	/* Change command source back to ARM */
+	aspeed_g4_privilege_ctrl(gpio, offset, GPIO_CMDSRC_ARM);
+
+	/* Update cache */
+	gpio->dcache[GPIO_BANK(offset)] = aspeed_g4_reg_bank_get(gpio, offset, reg_rdata);
+
+	return true;
+}
+
+static void aspeed_g4_copro_release(struct aspeed_gpio *gpio, unsigned int offset)
+{
+	if (!copro_ops || !gpio->cf_copro_bankmap)
+		return;
+	if (!gpio->cf_copro_bankmap[offset >> 3])
+		return;
+	if (!copro_ops->release_access)
+		return;
+
+	/* Change command source back to ColdFire */
+	aspeed_g4_privilege_ctrl(gpio, offset, GPIO_CMDSRC_COLDFIRE);
+
+	/* Restart the coprocessor */
+	copro_ops->release_access(copro_data);
+}
+
+static const struct aspeed_gpio_llops aspeed_g4_llops = {
+	.copro_request = aspeed_g4_copro_request,
+	.copro_release = aspeed_g4_copro_release,
+	.reg_bit_set = aspeed_g4_reg_bit_set,
+	.reg_bit_get = aspeed_g4_reg_bit_get,
+	.reg_bank_get = aspeed_g4_reg_bank_get,
+	.privilege_ctrl = aspeed_g4_privilege_ctrl,
+	.privilege_init = aspeed_g4_privilege_init,
+};
 /*
  * Any banks not specified in a struct aspeed_bank_props array are assumed to
  * have the properties:
@@ -1120,7 +1122,14 @@  static const struct aspeed_bank_props ast2400_bank_props[] = {
 
 static const struct aspeed_gpio_config ast2400_config =
 	/* 220 for simplicity, really 216 with two 4-GPIO holes, four at end */
-	{ .nr_gpios = 220, .props = ast2400_bank_props, };
+	{
+		.nr_gpios = 220,
+		.props = ast2400_bank_props,
+		.llops = &aspeed_g4_llops,
+		.debounce_timers_array = debounce_timers,
+		.debounce_timers_num = ARRAY_SIZE(debounce_timers),
+		.require_dcache = true,
+	};
 
 static const struct aspeed_bank_props ast2500_bank_props[] = {
 	/*     input	  output   */
@@ -1132,7 +1141,14 @@  static const struct aspeed_bank_props ast2500_bank_props[] = {
 
 static const struct aspeed_gpio_config ast2500_config =
 	/* 232 for simplicity, actual number is 228 (4-GPIO hole in GPIOAB) */
-	{ .nr_gpios = 232, .props = ast2500_bank_props, };
+	{
+		.nr_gpios = 232,
+		.props = ast2500_bank_props,
+		.llops = &aspeed_g4_llops,
+		.debounce_timers_array = debounce_timers,
+		.debounce_timers_num = ARRAY_SIZE(debounce_timers),
+		.require_dcache = true,
+	};
 
 static const struct aspeed_bank_props ast2600_bank_props[] = {
 	/*     input	  output   */
@@ -1148,7 +1164,14 @@  static const struct aspeed_gpio_config ast2600_config =
 	 * We expect ngpio being set in the device tree and this is a fallback
 	 * option.
 	 */
-	{ .nr_gpios = 208, .props = ast2600_bank_props, };
+	{
+		.nr_gpios = 208,
+		.props = ast2600_bank_props,
+		.llops = &aspeed_g4_llops,
+		.debounce_timers_array = debounce_timers,
+		.debounce_timers_num = ARRAY_SIZE(debounce_timers),
+		.require_dcache = true,
+	};
 
 static const struct of_device_id aspeed_gpio_of_table[] = {
 	{ .compatible = "aspeed,ast2400-gpio", .data = &ast2400_config, },
@@ -1191,6 +1214,10 @@  static int __init aspeed_gpio_probe(struct platform_device *pdev)
 
 	gpio->config = gpio_id->data;
 
+	if (!gpio->config->llops->reg_bit_set || !gpio->config->llops->reg_bit_get ||
+	    !gpio->config->llops->reg_bank_get)
+		return -EINVAL;
+
 	gpio->chip.parent = &pdev->dev;
 	err = of_property_read_u32(pdev->dev.of_node, "ngpios", &ngpio);
 	gpio->chip.ngpio = (u16) ngpio;
@@ -1207,27 +1234,23 @@  static int __init aspeed_gpio_probe(struct platform_device *pdev)
 	gpio->chip.label = dev_name(&pdev->dev);
 	gpio->chip.base = -1;
 
-	/* Allocate a cache of the output registers */
-	banks = DIV_ROUND_UP(gpio->chip.ngpio, 32);
-	gpio->dcache = devm_kcalloc(&pdev->dev,
-				    banks, sizeof(u32), GFP_KERNEL);
-	if (!gpio->dcache)
-		return -ENOMEM;
-
-	/*
-	 * Populate it with initial values read from the HW and switch
-	 * all command sources to the ARM by default
-	 */
-	for (i = 0; i < banks; i++) {
-		const struct aspeed_gpio_bank *bank = &aspeed_gpio_banks[i];
-		void __iomem *addr = bank_reg(gpio, bank, reg_rdata);
-		gpio->dcache[i] = ioread32(addr);
-		aspeed_gpio_change_cmd_source(gpio, bank, 0, GPIO_CMDSRC_ARM);
-		aspeed_gpio_change_cmd_source(gpio, bank, 1, GPIO_CMDSRC_ARM);
-		aspeed_gpio_change_cmd_source(gpio, bank, 2, GPIO_CMDSRC_ARM);
-		aspeed_gpio_change_cmd_source(gpio, bank, 3, GPIO_CMDSRC_ARM);
+	if (gpio->config->require_dcache) {
+		/* Allocate a cache of the output registers */
+		banks = DIV_ROUND_UP(gpio->chip.ngpio, 32);
+		gpio->dcache = devm_kcalloc(&pdev->dev, banks, sizeof(u32), GFP_KERNEL);
+		if (!gpio->dcache)
+			return -ENOMEM;
+		/*
+		 * Populate it with initial values read from the HW
+		 */
+		for (i = 0; i < banks; i++)
+			gpio->dcache[i] =
+				gpio->config->llops->reg_bank_get(gpio, (i << 5), reg_rdata);
 	}
 
+	if (gpio->config->llops->privilege_init)
+		gpio->config->llops->privilege_init(gpio);
+
 	/* Set up an irqchip */
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0)