SAMA7G5 reset controller has 5 extra lines that goes to different devices
(3 lines to USB PHYs, 1 line to DDR controller, 1 line to DDR PHY
controller). These reset lines could be requested by different controller
drivers (e.g. USB PHY driver) and these controllers' drivers could
assert/deassert these lines when necessary. Thus add support for
reset_controller_dev which brings this functionality.
Signed-off-by: Claudiu Beznea <[email protected]>
---
drivers/power/reset/at91-reset.c | 107 +++++++++++++++++++++++++++++--
1 file changed, 103 insertions(+), 4 deletions(-)
diff --git a/drivers/power/reset/at91-reset.c b/drivers/power/reset/at91-reset.c
index 1b2aca3f490d..a6f65ac430cd 100644
--- a/drivers/power/reset/at91-reset.c
+++ b/drivers/power/reset/at91-reset.c
@@ -17,10 +17,13 @@
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
+#include <linux/reset-controller.h>
#include <soc/at91/at91sam9_ddrsdr.h>
#include <soc/at91/at91sam9_sdramc.h>
+#include <dt-bindings/reset/sama7g5-reset.h>
+
#define AT91_RSTC_CR 0x00 /* Reset Controller Control Register */
#define AT91_RSTC_PROCRST BIT(0) /* Processor Reset */
#define AT91_RSTC_PERRST BIT(2) /* Peripheral Reset */
@@ -65,7 +68,10 @@ enum reset_type {
* struct at91_reset - AT91 reset specific data structure
* @rstc_base: base address for system reset
* @ramc_base: array with base addresses of RAM controllers
+ * @dev_base: base address for devices reset
* @sclk: slow clock
+ * @rcdev: reset controller device
+ * @lock: lock for devices reset register access
* @nb: reset notifier block
* @args: SoC specific system reset arguments
* @ramc_lpr: SDRAM Controller Low Power Register
@@ -73,12 +79,17 @@ enum reset_type {
struct at91_reset {
void __iomem *rstc_base;
void __iomem *ramc_base[2];
+ void __iomem *dev_base;
struct clk *sclk;
+ struct reset_controller_dev rcdev;
+ spinlock_t lock;
struct notifier_block nb;
u32 args;
u32 ramc_lpr;
};
+#define to_at91_reset(r) container_of(r, struct at91_reset, rcdev)
+
/**
* struct at91_reset_data - AT91 reset data
* @reset_args: SoC specific system reset arguments
@@ -216,6 +227,88 @@ static const struct of_device_id at91_reset_of_match[] = {
};
MODULE_DEVICE_TABLE(of, at91_reset_of_match);
+static int at91_reset_update(struct reset_controller_dev *rcdev,
+ unsigned long id, bool assert)
+{
+ struct at91_reset *reset = to_at91_reset(rcdev);
+ u32 val;
+
+ spin_lock(&reset->lock);
+ val = readl_relaxed(reset->dev_base);
+ if (assert)
+ val |= BIT(id);
+ else
+ val &= ~BIT(id);
+ writel_relaxed(val, reset->dev_base);
+ spin_unlock(&reset->lock);
+
+ return 0;
+}
+
+static int at91_reset_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ return at91_reset_update(rcdev, id, true);
+}
+
+static int at91_reset_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ return at91_reset_update(rcdev, id, false);
+}
+
+static int at91_reset_dev_status(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct at91_reset *reset = to_at91_reset(rcdev);
+ u32 val;
+
+ spin_lock(&reset->lock);
+ val = readl_relaxed(reset->dev_base);
+ spin_unlock(&reset->lock);
+
+ return !!(val & BIT(id));
+}
+
+static const struct reset_control_ops at91_reset_ops = {
+ .assert = at91_reset_assert,
+ .deassert = at91_reset_deassert,
+ .status = at91_reset_dev_status,
+};
+
+static int at91_reset_of_xlate(struct reset_controller_dev *rcdev,
+ const struct of_phandle_args *reset_spec)
+{
+ if (reset_spec->args[0] < SAMA7G5_RESET_USB_PHY1 ||
+ reset_spec->args[0] > SAMA7G5_RESET_USB_PHY3)
+ return -EINVAL;
+
+ return reset_spec->args[0];
+}
+
+static int at91_rcdev_init(struct at91_reset *reset,
+ const struct at91_reset_data *data,
+ struct platform_device *pdev)
+{
+ if (!data->n_device_reset)
+ return 0;
+
+ reset->dev_base = devm_of_iomap(&pdev->dev, pdev->dev.of_node, 1,
+ NULL);
+ if (IS_ERR(reset->dev_base))
+ return -ENODEV;
+
+ spin_lock_init(&reset->lock);
+ reset->rcdev.ops = &at91_reset_ops;
+ reset->rcdev.owner = THIS_MODULE;
+ reset->rcdev.of_node = pdev->dev.of_node;
+ reset->rcdev.nr_resets = data->n_device_reset;
+ reset->rcdev.of_reset_n_cells = 1;
+ reset->rcdev.of_xlate = at91_reset_of_xlate;
+
+ return devm_reset_controller_register(&pdev->dev, &reset->rcdev);
+}
+
static int __init at91_reset_probe(struct platform_device *pdev)
{
const struct of_device_id *match;
@@ -269,6 +362,10 @@ static int __init at91_reset_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, reset);
+ ret = at91_rcdev_init(reset, data, pdev);
+ if (ret)
+ goto disable_clk;
+
if (of_device_is_compatible(pdev->dev.of_node, "microchip,sam9x60-rstc")) {
u32 val = readl(reset->rstc_base + AT91_RSTC_MR);
@@ -277,14 +374,16 @@ static int __init at91_reset_probe(struct platform_device *pdev)
}
ret = register_restart_handler(&reset->nb);
- if (ret) {
- clk_disable_unprepare(reset->sclk);
- return ret;
- }
+ if (ret)
+ goto disable_clk;
at91_reset_status(pdev, reset->rstc_base);
return 0;
+
+disable_clk:
+ clk_disable_unprepare(reset->sclk);
+ return ret;
}
static int __exit at91_reset_remove(struct platform_device *pdev)
--
2.32.0
On Do, 2022-04-07 at 10:17 +0300, Claudiu Beznea wrote:
> SAMA7G5 reset controller has 5 extra lines that goes to different devices
> (3 lines to USB PHYs, 1 line to DDR controller, 1 line to DDR PHY
> controller). These reset lines could be requested by different controller
> drivers (e.g. USB PHY driver) and these controllers' drivers could
> assert/deassert these lines when necessary. Thus add support for
> reset_controller_dev which brings this functionality.
>
> Signed-off-by: Claudiu Beznea <[email protected]>
> ---
> drivers/power/reset/at91-reset.c | 107 +++++++++++++++++++++++++++++--
> 1 file changed, 103 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/power/reset/at91-reset.c b/drivers/power/reset/at91-reset.c
> index 1b2aca3f490d..a6f65ac430cd 100644
> --- a/drivers/power/reset/at91-reset.c
> +++ b/drivers/power/reset/at91-reset.c
[...]
> +static int at91_reset_update(struct reset_controller_dev *rcdev,
> + unsigned long id, bool assert)
> +{
> + struct at91_reset *reset = to_at91_reset(rcdev);
> + u32 val;
> +
> + spin_lock(&reset->lock);
Use spin_lock_irqsave. We don't know where we are called from and this
isn't a time critical path.
> + val = readl_relaxed(reset->dev_base);
> + if (assert)
> + val |= BIT(id);
> + else
> + val &= ~BIT(id);
> + writel_relaxed(val, reset->dev_base);
> + spin_unlock(&reset->lock);
> +
> + return 0;
> +}
> +
> +static int at91_reset_assert(struct reset_controller_dev *rcdev,
> + unsigned long id)
> +{
> + return at91_reset_update(rcdev, id, true);
> +}
> +
> +static int at91_reset_deassert(struct reset_controller_dev *rcdev,
> + unsigned long id)
> +{
> + return at91_reset_update(rcdev, id, false);
> +}
> +
> +static int at91_reset_dev_status(struct reset_controller_dev *rcdev,
> + unsigned long id)
> +{
> + struct at91_reset *reset = to_at91_reset(rcdev);
> + u32 val;
> +
> + spin_lock(&reset->lock);
Locking is not necessary here. If the read is racing against an update,
it either returns the register value before or after the update, same
as without a lock.
With those changes,
Reviewed-by: Philipp Zabel <[email protected]>
regards
Philipp