From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Stafford Horne <shorne@gmail.com>,
Karol Gugala <kgugala@antmicro.com>,
Mateusz Holenko <mholenko@antmicro.com>
Cc: Gabriel Somlo <gsomlo@gmail.com>,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
Geert Uytterhoeven <geert@linux-m68k.org>
Subject: [PATCH v4] drivers/soc/litex: Add restart handler
Date: Tue, 19 Jan 2021 09:09:38 +0100 [thread overview]
Message-ID: <20210119080938.1832733-1-geert@linux-m68k.org> (raw)
Let the LiteX SoC Controller register a restart handler, which resets
the LiteX SoC by writing 1 to CSR_CTRL_RESET_ADDR.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
v4:
- Drop bogus "a" from description,
- Get rid of static litex_soc_ctrl_device and litex_reset_nb
instances,
- Unregister handler on driver unbind,
v3:
- Rebase on top of openrisc/for-next,
v2:
- Rebase on top of v5.11-rc1,
- Change reset handler priority to recommended default value of 128
(was 192).
(v1 was not sent to a mailing list)
---
drivers/soc/litex/litex_soc_ctrl.c | 42 +++++++++++++++++++++++++++++-
1 file changed, 41 insertions(+), 1 deletion(-)
diff --git a/drivers/soc/litex/litex_soc_ctrl.c b/drivers/soc/litex/litex_soc_ctrl.c
index da17ba56b7956c84..a7dd5be9fd5bd8ad 100644
--- a/drivers/soc/litex/litex_soc_ctrl.c
+++ b/drivers/soc/litex/litex_soc_ctrl.c
@@ -15,6 +15,11 @@
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/io.h>
+#include <linux/reboot.h>
+
+/* reset register located at the base address */
+#define RESET_REG_OFF 0x00
+#define RESET_REG_VALUE 0x00000001
#define SCRATCH_REG_OFF 0x04
#define SCRATCH_REG_VALUE 0x12345678
@@ -66,8 +71,19 @@ static int litex_check_csr_access(void __iomem *reg_addr)
struct litex_soc_ctrl_device {
void __iomem *base;
+ struct notifier_block reset_nb;
};
+static int litex_reset_handler(struct notifier_block *this, unsigned long mode,
+ void *cmd)
+{
+ struct litex_soc_ctrl_device *soc_ctrl_dev =
+ container_of(this, struct litex_soc_ctrl_device, reset_nb);
+
+ litex_write32(soc_ctrl_dev->base + RESET_REG_OFF, RESET_REG_VALUE);
+ return NOTIFY_DONE;
+}
+
static const struct of_device_id litex_soc_ctrl_of_match[] = {
{.compatible = "litex,soc-controller"},
{},
@@ -78,6 +94,7 @@ MODULE_DEVICE_TABLE(of, litex_soc_ctrl_of_match);
static int litex_soc_ctrl_probe(struct platform_device *pdev)
{
struct litex_soc_ctrl_device *soc_ctrl_dev;
+ int error;
soc_ctrl_dev = devm_kzalloc(&pdev->dev, sizeof(*soc_ctrl_dev), GFP_KERNEL);
if (!soc_ctrl_dev)
@@ -87,7 +104,29 @@ static int litex_soc_ctrl_probe(struct platform_device *pdev)
if (IS_ERR(soc_ctrl_dev->base))
return PTR_ERR(soc_ctrl_dev->base);
- return litex_check_csr_access(soc_ctrl_dev->base);
+ error = litex_check_csr_access(soc_ctrl_dev->base);
+ if (error)
+ return error;
+
+ platform_set_drvdata(pdev, soc_ctrl_dev);
+
+ soc_ctrl_dev->reset_nb.notifier_call = litex_reset_handler;
+ soc_ctrl_dev->reset_nb.priority = 128;
+ error = register_restart_handler(&soc_ctrl_dev->reset_nb);
+ if (error) {
+ dev_warn(&pdev->dev, "cannot register restart handler: %d\n",
+ error);
+ }
+
+ return 0;
+}
+
+static int litex_soc_ctrl_remove(struct platform_device *pdev)
+{
+ struct litex_soc_ctrl_device *soc_ctrl_dev = platform_get_drvdata(pdev);
+
+ unregister_restart_handler(&soc_ctrl_dev->reset_nb);
+ return 0;
}
static struct platform_driver litex_soc_ctrl_driver = {
@@ -96,6 +135,7 @@ static struct platform_driver litex_soc_ctrl_driver = {
.of_match_table = of_match_ptr(litex_soc_ctrl_of_match)
},
.probe = litex_soc_ctrl_probe,
+ .remove = litex_soc_ctrl_remove,
};
module_platform_driver(litex_soc_ctrl_driver);
--
2.25.1
next reply other threads:[~2021-01-19 8:11 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-19 8:09 Geert Uytterhoeven [this message]
2021-01-19 8:17 ` [PATCH v4] drivers/soc/litex: Add restart handler Anup Patel
2021-01-20 8:21 ` Geert Uytterhoeven
2021-01-19 21:34 ` Stafford Horne
2021-01-19 22:11 ` Stafford Horne
2021-01-20 8:20 ` Geert Uytterhoeven
2021-01-20 13:06 ` Stafford Horne
2021-01-20 21:46 ` Joel Stanley
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