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

Jan Dakinevich
2024-07-18T02:41:02Z

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@baylibre.com>
> ---
> 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