Re: [PATCH 1/8] reset: amlogic: convert driver to regmap

[Jan Dakinevich]

On 7/10/24 19:25, Jerome Brunet wrote:
> To allow using the same driver for the main reset controller and the
> auxiliary ones embedded in the clock controllers, convert the
> the Amlogic reset driver to regmap.
> 
> Signed-off-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx>
> ---
>  drivers/reset/reset-meson.c | 80 ++++++++++++++++++++-----------------
>  1 file changed, 44 insertions(+), 36 deletions(-)
> 
> diff --git a/drivers/reset/reset-meson.c b/drivers/reset/reset-meson.c
> index f78be97898bc..8f3d6e9df235 100644
> --- a/drivers/reset/reset-meson.c
> +++ b/drivers/reset/reset-meson.c
> @@ -11,36 +11,44 @@
>  #include <linux/of.h>
>  #include <linux/module.h>
>  #include <linux/platform_device.h>
> +#include <linux/regmap.h>
>  #include <linux/reset-controller.h>
>  #include <linux/slab.h>
>  #include <linux/types.h>
>  
> -#define BITS_PER_REG	32
> -
>  struct meson_reset_param {
>  	int reg_count;
>  	int level_offset;
>  };
>  
>  struct meson_reset {
> -	void __iomem *reg_base;
>  	const struct meson_reset_param *param;
>  	struct reset_controller_dev rcdev;
> -	spinlock_t lock;
> +	struct regmap *map;
>  };
>  
> +static void meson_reset_offset_and_bit(struct meson_reset *data,
> +				       unsigned long id,
> +				       unsigned int *offset,
> +				       unsigned int *bit)
> +{
> +	unsigned int stride = regmap_get_reg_stride(data->map);
> +
> +	*offset = (id / (stride * BITS_PER_BYTE)) * stride;
> +	*bit = id % (stride * BITS_PER_BYTE);
> +}
> +
>  static int meson_reset_reset(struct reset_controller_dev *rcdev,
> -			      unsigned long id)
> +			     unsigned long id)
>  {
>  	struct meson_reset *data =
>  		container_of(rcdev, struct meson_reset, rcdev);
> -	unsigned int bank = id / BITS_PER_REG;
> -	unsigned int offset = id % BITS_PER_REG;
> -	void __iomem *reg_addr = data->reg_base + (bank << 2);
> +	unsigned int offset, bit;
>  
> -	writel(BIT(offset), reg_addr);
> +	meson_reset_offset_and_bit(data, id, &offset, &bit);
>  
> -	return 0;
> +	return regmap_update_bits(data->map, offset,
> +				  BIT(bit), BIT(bit));

regmap_update_bits() is not equal to writel(), I suppose regmap_write()
should be here.

I'm still under testing, but I see unexpected behavior on A1 SoC:

[    1.482446] Call trace:
[    1.484860]  dump_backtrace+0x94/0xec
[    1.488482]  show_stack+0x18/0x24
[    1.491754]  dump_stack_lvl+0x78/0x90
[    1.495377]  dump_stack+0x18/0x24
[    1.498654]  __report_bad_irq+0x38/0xe4
[    1.502453]  note_interrupt+0x324/0x374
[    1.506244]  handle_irq_event+0x9c/0xac
[    1.510039]  handle_fasteoi_irq+0xa4/0x238
[    1.514093]  generic_handle_domain_irq+0x2c/0x44
[    1.518664]  gic_handle_irq+0x40/0xc4
[    1.522287]  call_on_irq_stack+0x24/0x4c
[    1.526168]  do_interrupt_handler+0x80/0x84
[    1.530308]  el1_interrupt+0x34/0x68
[    1.533844]  el1h_64_irq_handler+0x18/0x24
[    1.537898]  el1h_64_irq+0x64/0x68
[    1.541262]  default_idle_call+0x28/0x3c
[    1.545143]  do_idle+0x208/0x260
[    1.548334]  cpu_startup_entry+0x38/0x3c
[    1.552220]  kernel_init+0x0/0x1dc
[    1.555579]  start_kernel+0x5ac/0x6f0
[    1.559206]  __primary_switched+0x80/0x88


and using of regmap_write() (apparently) fixes it.

>  }
>  
>  static int meson_reset_level(struct reset_controller_dev *rcdev,
> @@ -48,25 +56,13 @@ static int meson_reset_level(struct reset_controller_dev *rcdev,
>  {
>  	struct meson_reset *data =
>  		container_of(rcdev, struct meson_reset, rcdev);
> -	unsigned int bank = id / BITS_PER_REG;
> -	unsigned int offset = id % BITS_PER_REG;
> -	void __iomem *reg_addr;
> -	unsigned long flags;
> -	u32 reg;
> +	unsigned int offset, bit;
>  
> -	reg_addr = data->reg_base + data->param->level_offset + (bank << 2);
> +	meson_reset_offset_and_bit(data, id, &offset, &bit);
> +	offset += data->param->level_offset;
>  
> -	spin_lock_irqsave(&data->lock, flags);
> -
> -	reg = readl(reg_addr);
> -	if (assert)
> -		writel(reg & ~BIT(offset), reg_addr);
> -	else
> -		writel(reg | BIT(offset), reg_addr);
> -
> -	spin_unlock_irqrestore(&data->lock, flags);
> -
> -	return 0;
> +	return regmap_update_bits(data->map, offset,
> +				  BIT(bit), assert ? 0 : BIT(bit));
>  }
>  
>  static int meson_reset_assert(struct reset_controller_dev *rcdev,
> @@ -113,30 +109,42 @@ static const struct of_device_id meson_reset_dt_ids[] = {
>  };
>  MODULE_DEVICE_TABLE(of, meson_reset_dt_ids);
>  
> +static const struct regmap_config regmap_config = {
> +	.reg_bits   = 32,
> +	.val_bits   = 32,
> +	.reg_stride = 4,
> +};
> +
>  static int meson_reset_probe(struct platform_device *pdev)
>  {
> +	struct device *dev = &pdev->dev;
>  	struct meson_reset *data;
> +	void __iomem *base;
>  
> -	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> +	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
>  	if (!data)
>  		return -ENOMEM;
>  
> -	data->reg_base = devm_platform_ioremap_resource(pdev, 0);
> -	if (IS_ERR(data->reg_base))
> -		return PTR_ERR(data->reg_base);
> +	base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
>  
> -	data->param = of_device_get_match_data(&pdev->dev);
> +	data->param = of_device_get_match_data(dev);
>  	if (!data->param)
>  		return -ENODEV;
>  
> -	spin_lock_init(&data->lock);
> +	data->map = devm_regmap_init_mmio(dev, base, &regmap_config);
> +	if (IS_ERR(data->map))
> +		return dev_err_probe(dev, PTR_ERR(data->map),
> +				     "can't init regmap mmio region\n");
>  
>  	data->rcdev.owner = THIS_MODULE;
> -	data->rcdev.nr_resets = data->param->reg_count * BITS_PER_REG;
> +	data->rcdev.nr_resets = data->param->reg_count * BITS_PER_BYTE
> +		* regmap_config.reg_stride;
>  	data->rcdev.ops = &meson_reset_ops;
> -	data->rcdev.of_node = pdev->dev.of_node;
> +	data->rcdev.of_node = dev->of_node;
>  
> -	return devm_reset_controller_register(&pdev->dev, &data->rcdev);
> +	return devm_reset_controller_register(dev, &data->rcdev);
>  }
>  
>  static struct platform_driver meson_reset_driver = {

-- 
Best regards
Jan Dakinevich