* [PATCH v3 2/2] hwrng: starfive: rework clk/reset teardown order for JHB100 & fix RPM
2026-06-01 9:37 [PATCH v3 0/2] hwrng: starfive: updates for jh7110-trng DT binding and driver fixes lianfeng.ouyang
2026-06-01 9:37 ` [PATCH v3 1/2] dt-bindings: rng: starfive,jh7110-trng: add jhb100, drop jh8100 lianfeng.ouyang
@ 2026-06-01 9:37 ` lianfeng.ouyang
2026-06-01 10:16 ` sashiko-bot
1 sibling, 1 reply; 4+ messages in thread
From: lianfeng.ouyang @ 2026-06-01 9:37 UTC (permalink / raw)
To: Olivia Mackall, Herbert Xu, Rob Herring, Krzysztof Kozlowski,
Conor Dooley, Philipp Zabel
Cc: linux-crypto, devicetree, linux-kernel, Lianfeng Ouyang
From: Lianfeng Ouyang <lianfeng.ouyang@starfivetech.com>
JHB100: to avoid RDC glitch, assert reset only after clocks are gated.
Introduce a per-compatible seq_rst_clk flag (RST_FIRST/CLK_FIRST)
selected via of_device_get_match_data().
RPM fixes:
- Mark device RPM_ACTIVE in probe after clocks & reset deassert,
before pm_runtime_enable(), so usage count can eventually drop to 0
and autosuspend actually triggers.
- Balance pm_runtime_get/put in init/read/cleanup, and reject
register access when RPM resume fails.
- Move low-level disable/reset into a devm action
(starfive_trng_release()) so error-path unwind order is correct.
Signed-off-by: Lianfeng Ouyang <lianfeng.ouyang@starfivetech.com>
---
MAINTAINERS | 2 +-
drivers/char/hw_random/jh7110-trng.c | 191 +++++++++++++++++++++------
2 files changed, 148 insertions(+), 45 deletions(-)
diff --git a/MAINTAINERS b/MAINTAINERS
index d3a6b3f6b6a0..729b20ecc697 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -25280,7 +25280,7 @@ F: Documentation/devicetree/bindings/perf/starfive,jh8100-starlink-pmu.yaml
F: drivers/perf/starfive_starlink_pmu.c
STARFIVE TRNG DRIVER
-M: Jia Jie Ho <jiajie.ho@starfivetech.com>
+M: Lianfeng Ouyang <lianfeng.ouyang@starfivetech.com>
S: Supported
F: Documentation/devicetree/bindings/rng/starfive*
F: drivers/char/hw_random/jh7110-trng.c
diff --git a/drivers/char/hw_random/jh7110-trng.c b/drivers/char/hw_random/jh7110-trng.c
index 9776f4daa044..9c164a0011ae 100644
--- a/drivers/char/hw_random/jh7110-trng.c
+++ b/drivers/char/hw_random/jh7110-trng.c
@@ -92,20 +92,36 @@ enum mode {
PRNG_256BIT,
};
+/*
+ * For JHB100, assert reset after disabling clocks to avoid
+ * reset-domain crossing (RDC) induced glitches that can affect
+ * downstream IPs.
+ */
+enum seq_rst_clk {
+ SEQ_RST_FIRST,
+ SEQ_CLK_FIRST,
+};
+
+struct starfive_trng_data {
+ enum seq_rst_clk seq_rst_clk;
+};
+
struct starfive_trng {
- struct device *dev;
- void __iomem *base;
- struct clk *hclk;
- struct clk *ahb;
- struct reset_control *rst;
- struct hwrng rng;
- struct completion random_done;
- struct completion reseed_done;
- u32 mode;
- u32 mission;
- u32 reseed;
- /* protects against concurrent write to ctrl register */
- spinlock_t write_lock;
+ struct device *dev;
+ void __iomem *base;
+ int irq;
+ struct clk *hclk;
+ struct clk *ahb;
+ struct reset_control *rst;
+ struct hwrng rng;
+ struct completion random_done;
+ struct completion reseed_done;
+ const struct starfive_trng_data *data;
+ u32 mode;
+ u32 mission;
+ u32 reseed;
+ struct mutex lock; /* protect trng cmd seq */
+ spinlock_t write_lock; /* protects register access seq */
};
static u16 autoreq;
@@ -130,7 +146,7 @@ static inline int starfive_trng_wait_idle(struct starfive_trng *trng)
10, 100000);
}
-static inline void starfive_trng_irq_mask_clear(struct starfive_trng *trng)
+static inline void starfive_trng_irq_clear(struct starfive_trng *trng)
{
/* clear register: ISTAT */
u32 data = readl(trng->base + STARFIVE_ISTAT);
@@ -138,6 +154,31 @@ static inline void starfive_trng_irq_mask_clear(struct starfive_trng *trng)
writel(data, trng->base + STARFIVE_ISTAT);
}
+static void starfive_trng_release(void *data)
+{
+ struct starfive_trng *trng = data;
+
+ if (!pm_runtime_status_suspended(trng->dev)) {
+ writel(0, trng->base + STARFIVE_IE);
+ starfive_trng_irq_clear(trng);
+
+ if (trng->irq >= 0)
+ synchronize_irq(trng->irq);
+
+ if (trng->data->seq_rst_clk == SEQ_RST_FIRST)
+ reset_control_assert(trng->rst);
+
+ clk_disable_unprepare(trng->ahb);
+ clk_disable_unprepare(trng->hclk);
+
+ if (trng->data->seq_rst_clk == SEQ_CLK_FIRST)
+ reset_control_assert(trng->rst);
+ }
+
+ pm_runtime_dont_use_autosuspend(trng->dev);
+ pm_runtime_disable(trng->dev);
+}
+
static int starfive_trng_cmd(struct starfive_trng *trng, u32 cmd, bool wait)
{
int wait_time = 1000;
@@ -174,13 +215,22 @@ static int starfive_trng_init(struct hwrng *rng)
{
struct starfive_trng *trng = to_trng(rng);
u32 mode, intr = 0;
+ int ret;
+
+ ret = pm_runtime_resume_and_get(trng->dev);
+ if (ret < 0) {
+ dev_warn(trng->dev, "Failed to wake device for init: %d\n", ret);
+ return ret;
+ }
+
+ mutex_lock(&trng->lock);
/* setup Auto Request/Age register */
writel(autoage, trng->base + STARFIVE_AUTO_AGE);
writel(autoreq, trng->base + STARFIVE_AUTO_RQSTS);
/* clear register: ISTAT */
- starfive_trng_irq_mask_clear(trng);
+ starfive_trng_irq_clear(trng);
intr |= STARFIVE_IE_ALL;
writel(intr, trng->base + STARFIVE_IE);
@@ -201,7 +251,13 @@ static int starfive_trng_init(struct hwrng *rng)
writel(mode, trng->base + STARFIVE_MODE);
- return starfive_trng_cmd(trng, STARFIVE_CTRL_EXEC_RANDRESEED, 1);
+ ret = starfive_trng_cmd(trng, STARFIVE_CTRL_EXEC_RANDRESEED, 1);
+
+ mutex_unlock(&trng->lock);
+
+ pm_runtime_put_autosuspend(trng->dev);
+
+ return ret;
}
static irqreturn_t starfive_trng_irq(int irq, void *priv)
@@ -209,16 +265,17 @@ static irqreturn_t starfive_trng_irq(int irq, void *priv)
u32 status;
struct starfive_trng *trng = (struct starfive_trng *)priv;
+ if (!pm_runtime_get_if_active(trng->dev)) {
+ dev_err_ratelimited(trng->dev, "pm is inactive in irq\n");
+ return IRQ_NONE;
+ }
+
status = readl(trng->base + STARFIVE_ISTAT);
- if (status & STARFIVE_ISTAT_RAND_RDY) {
+ if (status & STARFIVE_ISTAT_RAND_RDY)
writel(STARFIVE_ISTAT_RAND_RDY, trng->base + STARFIVE_ISTAT);
- complete(&trng->random_done);
- }
- if (status & STARFIVE_ISTAT_SEED_DONE) {
+ if (status & STARFIVE_ISTAT_SEED_DONE)
writel(STARFIVE_ISTAT_SEED_DONE, trng->base + STARFIVE_ISTAT);
- complete(&trng->reseed_done);
- }
if (status & STARFIVE_ISTAT_LFSR_LOCKUP) {
writel(STARFIVE_ISTAT_LFSR_LOCKUP, trng->base + STARFIVE_ISTAT);
@@ -228,18 +285,37 @@ static irqreturn_t starfive_trng_irq(int irq, void *priv)
spin_unlock(&trng->write_lock);
}
+ if (status & STARFIVE_ISTAT_RAND_RDY)
+ complete(&trng->random_done);
+
+ if (status & STARFIVE_ISTAT_SEED_DONE)
+ complete(&trng->reseed_done);
+
+ pm_runtime_put_noidle(trng->dev);
+
return IRQ_HANDLED;
}
static void starfive_trng_cleanup(struct hwrng *rng)
{
struct starfive_trng *trng = to_trng(rng);
+ int ret;
+
+ ret = pm_runtime_resume_and_get(trng->dev);
+ if (ret < 0) {
+ dev_warn(trng->dev, "Failed to wake device for cleanup: %d\n", ret);
+ return;
+ }
+
+ writel(0, trng->base + STARFIVE_IE);
+ starfive_trng_irq_clear(trng);
+
+ if (trng->irq >= 0)
+ synchronize_irq(trng->irq);
writel(0, trng->base + STARFIVE_CTRL);
- reset_control_assert(trng->rst);
- clk_disable_unprepare(trng->hclk);
- clk_disable_unprepare(trng->ahb);
+ pm_runtime_put_sync(trng->dev);
}
static int starfive_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
@@ -247,7 +323,13 @@ static int starfive_trng_read(struct hwrng *rng, void *buf, size_t max, bool wai
struct starfive_trng *trng = to_trng(rng);
int ret;
- pm_runtime_get_sync(trng->dev);
+ ret = pm_runtime_resume_and_get(trng->dev);
+ if (ret < 0) {
+ dev_warn(trng->dev, "Failed to wake device for read: %d\n", ret);
+ return ret;
+ }
+
+ mutex_lock(&trng->lock);
if (trng->mode == PRNG_256BIT)
max = min_t(size_t, max, (STARFIVE_RAND_LEN * 8));
@@ -257,24 +339,28 @@ static int starfive_trng_read(struct hwrng *rng, void *buf, size_t max, bool wai
if (wait) {
ret = starfive_trng_wait_idle(trng);
if (ret)
- return -ETIMEDOUT;
+ goto end;
}
ret = starfive_trng_cmd(trng, STARFIVE_CTRL_GENE_RANDNUM, wait);
if (ret)
- return ret;
+ goto end;
memcpy_fromio(buf, trng->base + STARFIVE_RAND0, max);
- pm_runtime_put_sync_autosuspend(trng->dev);
+ ret = max;
+
+end:
+ mutex_unlock(&trng->lock);
- return max;
+ pm_runtime_put_autosuspend(trng->dev);
+
+ return ret;
}
static int starfive_trng_probe(struct platform_device *pdev)
{
int ret;
- int irq;
struct starfive_trng *trng;
trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
@@ -282,22 +368,32 @@ static int starfive_trng_probe(struct platform_device *pdev)
return -ENOMEM;
platform_set_drvdata(pdev, trng);
+
trng->dev = &pdev->dev;
+ trng->data = of_device_get_match_data(&pdev->dev);
+ if (!trng->data)
+ return -EINVAL;
+
+ if (trng->data->seq_rst_clk != SEQ_RST_FIRST && trng->data->seq_rst_clk != SEQ_CLK_FIRST) {
+ dev_err(&pdev->dev, "Unknown seq_rst_clk value\n");
+ return -EINVAL;
+ }
trng->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(trng->base))
return dev_err_probe(&pdev->dev, PTR_ERR(trng->base),
"Error remapping memory for platform device.\n");
- irq = platform_get_irq(pdev, 0);
- if (irq < 0)
- return irq;
+ trng->irq = platform_get_irq(pdev, 0);
+ if (trng->irq < 0)
+ return trng->irq;
init_completion(&trng->random_done);
init_completion(&trng->reseed_done);
+ mutex_init(&trng->lock);
spin_lock_init(&trng->write_lock);
- ret = devm_request_irq(&pdev->dev, irq, starfive_trng_irq, 0, pdev->name,
+ ret = devm_request_irq(&pdev->dev, trng->irq, starfive_trng_irq, 0, pdev->name,
(void *)trng);
if (ret)
return dev_err_probe(&pdev->dev, ret,
@@ -333,18 +429,16 @@ static int starfive_trng_probe(struct platform_device *pdev)
pm_runtime_use_autosuspend(&pdev->dev);
pm_runtime_set_autosuspend_delay(&pdev->dev, 100);
+ pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);
- ret = devm_hwrng_register(&pdev->dev, &trng->rng);
- if (ret) {
- pm_runtime_disable(&pdev->dev);
-
- reset_control_assert(trng->rst);
- clk_disable_unprepare(trng->ahb);
- clk_disable_unprepare(trng->hclk);
+ ret = devm_add_action_or_reset(&pdev->dev, starfive_trng_release, trng);
+ if (ret)
+ return ret;
+ ret = devm_hwrng_register(&pdev->dev, &trng->rng);
+ if (ret)
return dev_err_probe(&pdev->dev, ret, "Failed to register hwrng\n");
- }
return 0;
}
@@ -376,8 +470,17 @@ static const struct dev_pm_ops starfive_trng_pm_ops = {
starfive_trng_resume, NULL)
};
+static const struct starfive_trng_data jh7110_data = {
+ .seq_rst_clk = SEQ_RST_FIRST,
+};
+
+static const struct starfive_trng_data jhb100_data = {
+ .seq_rst_clk = SEQ_CLK_FIRST,
+};
+
static const struct of_device_id trng_dt_ids[] __maybe_unused = {
- { .compatible = "starfive,jh7110-trng" },
+ { .compatible = "starfive,jh7110-trng", .data = &jh7110_data },
+ { .compatible = "starfive,jhb100-trng", .data = &jhb100_data },
{ }
};
MODULE_DEVICE_TABLE(of, trng_dt_ids);
--
2.43.0
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