This patch series adds kernel support for StarFive hardware random
number generator. First 2 patches add binding docs and device driver for
this module. Patch 3 adds devicetree entry for VisionFive 2 SoC.
Patch 3 needs to be applied on top of:
https://patchwork.kernel.org/project/linux-riscv/patch/[email protected]/
Patch 3 also depends on additional clock and reset patches for stg domain
that are yet to be submitted to mailing list.
Changes v3 -> v4:
- move init completion before IRQ registration to be prepared for
spurious interrupts. (Herbert)
- add locks to guard concurrent write to same register in Patch 2.
(Herbert)
Changes v2 -> v3:
- use constant usecs and convert to jiffies in Patch 2. (Herbert)
- remove sleep in irq handler in Patch 2. (Herbert)
- limit wait timer to 40us if wait == 0 for trng read. (Herbert)
Changes v1 -> v2:
- updated of_match_ptr and added pm_sleep_ptr in Patch 2. (by Krzysztof)
- drop "status" in dts as module is always on in Patch 3. (by Krzysztof)
Jia Jie Ho (3):
dt-bindings: rng: Add StarFive TRNG module
hwrng: starfive - Add TRNG driver for StarFive SoC
riscv: dts: starfive: Add TRNG node for VisionFive 2
.../bindings/rng/starfive,jh7110-trng.yaml | 55 +++
MAINTAINERS | 6 +
arch/riscv/boot/dts/starfive/jh7110.dtsi | 10 +
drivers/char/hw_random/Kconfig | 11 +
drivers/char/hw_random/Makefile | 1 +
drivers/char/hw_random/starfive-trng.c | 397 ++++++++++++++++++
6 files changed, 480 insertions(+)
create mode 100644 Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml
create mode 100644 drivers/char/hw_random/starfive-trng.c
--
2.25.1
Add documentation to describe Starfive true random number generator
module.
Co-developed-by: Jenny Zhang <[email protected]>
Signed-off-by: Jenny Zhang <[email protected]>
Signed-off-by: Jia Jie Ho <[email protected]>
Reviewed-by: Krzysztof Kozlowski <[email protected]>
Reviewed-by: Conor Dooley <[email protected]>
---
.../bindings/rng/starfive,jh7110-trng.yaml | 55 +++++++++++++++++++
1 file changed, 55 insertions(+)
create mode 100644 Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml
diff --git a/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml b/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml
new file mode 100644
index 000000000000..2b76ce25acc4
--- /dev/null
+++ b/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml
@@ -0,0 +1,55 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/rng/starfive,jh7110-trng.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: StarFive SoC TRNG Module
+
+maintainers:
+ - Jia Jie Ho <[email protected]>
+
+properties:
+ compatible:
+ const: starfive,jh7110-trng
+
+ reg:
+ maxItems: 1
+
+ clocks:
+ items:
+ - description: Hardware reference clock
+ - description: AHB reference clock
+
+ clock-names:
+ items:
+ - const: hclk
+ - const: ahb
+
+ resets:
+ maxItems: 1
+
+ interrupts:
+ maxItems: 1
+
+required:
+ - compatible
+ - reg
+ - clocks
+ - clock-names
+ - resets
+ - interrupts
+
+additionalProperties: false
+
+examples:
+ - |
+ rng: rng@1600C000 {
+ compatible = "starfive,jh7110-trng";
+ reg = <0x1600C000 0x4000>;
+ clocks = <&clk 15>, <&clk 16>;
+ clock-names = "hclk", "ahb";
+ resets = <&reset 3>;
+ interrupts = <30>;
+ };
+...
--
2.25.1
This adds driver support for the hardware random number generator in
Starfive SoCs and adds StarFive TRNG entry to MAINTAINERS.
Co-developed-by: Jenny Zhang <[email protected]>
Signed-off-by: Jenny Zhang <[email protected]>
Signed-off-by: Jia Jie Ho <[email protected]>
---
MAINTAINERS | 6 +
drivers/char/hw_random/Kconfig | 11 +
drivers/char/hw_random/Makefile | 1 +
drivers/char/hw_random/starfive-trng.c | 397 +++++++++++++++++++++++++
4 files changed, 415 insertions(+)
create mode 100644 drivers/char/hw_random/starfive-trng.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 65140500d9f8..b91e3fc11fc6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -19626,6 +19626,12 @@ F: drivers/reset/reset-starfive.c
F: include/linux/reset/starfive.h
F: include/dt-bindings/reset/starfive*
+STARFIVE TRNG DRIVER
+M: Jia Jie Ho <[email protected]>
+S: Maintained
+F: Documentation/devicetree/bindings/rng/starfive*
+F: drivers/char/hw_random/starfive-trng.c
+
STATIC BRANCH/CALL
M: Peter Zijlstra <[email protected]>
M: Josh Poimboeuf <[email protected]>
diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index 3da8e85f8aae..ddd7ada7f877 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -549,6 +549,17 @@ config HW_RANDOM_CN10K
To compile this driver as a module, choose M here.
The module will be called cn10k_rng. If unsure, say Y.
+config HW_RANDOM_STARFIVE
+ tristate "StarFive HW Random Number Generator support"
+ depends on SOC_STARFIVE
+ depends on HW_RANDOM
+ help
+ This driver provides support for the Hardware Random Number
+ Generator in StarFive SoCs.
+
+ To compile this driver as a module, choose M here.
+ The module will be called starfive-trng.
+
endif # HW_RANDOM
config UML_RANDOM
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index 3e948cf04476..f68ac370847f 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -47,3 +47,4 @@ obj-$(CONFIG_HW_RANDOM_XIPHERA) += xiphera-trng.o
obj-$(CONFIG_HW_RANDOM_ARM_SMCCC_TRNG) += arm_smccc_trng.o
obj-$(CONFIG_HW_RANDOM_CN10K) += cn10k-rng.o
obj-$(CONFIG_HW_RANDOM_POLARFIRE_SOC) += mpfs-rng.o
+obj-$(CONFIG_HW_RANDOM_STARFIVE) += starfive-trng.o
diff --git a/drivers/char/hw_random/starfive-trng.c b/drivers/char/hw_random/starfive-trng.c
new file mode 100644
index 000000000000..a906f5dd4c19
--- /dev/null
+++ b/drivers/char/hw_random/starfive-trng.c
@@ -0,0 +1,397 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * TRNG driver for the StarFive SoC
+ *
+ * Copyright (C) 2022 StarFive Technology Co.
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/hw_random.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/random.h>
+#include <linux/reset.h>
+
+/* trng register offset */
+#define STARFIVE_CTRL 0x00
+#define STARFIVE_STAT 0x04
+#define STARFIVE_MODE 0x08
+#define STARFIVE_SMODE 0x0C
+#define STARFIVE_IE 0x10
+#define STARFIVE_ISTAT 0x14
+#define STARFIVE_RAND0 0x20
+#define STARFIVE_RAND1 0x24
+#define STARFIVE_RAND2 0x28
+#define STARFIVE_RAND3 0x2C
+#define STARFIVE_RAND4 0x30
+#define STARFIVE_RAND5 0x34
+#define STARFIVE_RAND6 0x38
+#define STARFIVE_RAND7 0x3C
+#define STARFIVE_AUTO_RQSTS 0x60
+#define STARFIVE_AUTO_AGE 0x64
+
+/* CTRL CMD */
+#define STARFIVE_CTRL_EXEC_NOP 0x0
+#define STARFIVE_CTRL_GENE_RANDNUM 0x1
+#define STARFIVE_CTRL_EXEC_RANDRESEED 0x2
+
+/* STAT */
+#define STARFIVE_STAT_NONCE_MODE BIT(2)
+#define STARFIVE_STAT_R256 BIT(3)
+#define STARFIVE_STAT_MISSION_MODE BIT(8)
+#define STARFIVE_STAT_SEEDED BIT(9)
+#define STARFIVE_STAT_LAST_RESEED(x) ((x) << 16)
+#define STARFIVE_STAT_SRVC_RQST BIT(27)
+#define STARFIVE_STAT_RAND_GENERATING BIT(30)
+#define STARFIVE_STAT_RAND_SEEDING BIT(31)
+
+/* MODE */
+#define STARFIVE_MODE_R256 BIT(3)
+
+/* SMODE */
+#define STARFIVE_SMODE_NONCE_MODE BIT(2)
+#define STARFIVE_SMODE_MISSION_MODE BIT(8)
+#define STARFIVE_SMODE_MAX_REJECTS(x) ((x) << 16)
+
+/* IE */
+#define STARFIVE_IE_RAND_RDY_EN BIT(0)
+#define STARFIVE_IE_SEED_DONE_EN BIT(1)
+#define STARFIVE_IE_LFSR_LOCKUP_EN BIT(4)
+#define STARFIVE_IE_GLBL_EN BIT(31)
+
+#define STARFIVE_IE_ALL (STARFIVE_IE_GLBL_EN | \
+ STARFIVE_IE_RAND_RDY_EN | \
+ STARFIVE_IE_SEED_DONE_EN | \
+ STARFIVE_IE_LFSR_LOCKUP_EN)
+
+/* ISTAT */
+#define STARFIVE_ISTAT_RAND_RDY BIT(0)
+#define STARFIVE_ISTAT_SEED_DONE BIT(1)
+#define STARFIVE_ISTAT_LFSR_LOCKUP BIT(4)
+
+#define STARFIVE_RAND_LEN sizeof(u32)
+
+#define to_trng(p) container_of(p, struct starfive_trng, rng)
+
+enum reseed {
+ RANDOM_RESEED,
+ NONCE_RESEED,
+};
+
+enum mode {
+ PRNG_128BIT,
+ PRNG_256BIT,
+};
+
+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;
+};
+
+static u16 autoreq;
+module_param(autoreq, ushort, 0);
+MODULE_PARM_DESC(autoreq, "Auto-reseeding after random number requests by host reaches specified counter:\n"
+ " 0 - disable counter\n"
+ " other - reload value for internal counter");
+
+static u16 autoage;
+module_param(autoage, ushort, 0);
+MODULE_PARM_DESC(autoage, "Auto-reseeding after specified timer countdowns to 0:\n"
+ " 0 - disable timer\n"
+ " other - reload value for internal timer");
+
+static inline int starfive_trng_wait_idle(struct starfive_trng *trng)
+{
+ u32 stat;
+
+ return readl_relaxed_poll_timeout(trng->base + STARFIVE_STAT, stat,
+ !(stat & (STARFIVE_STAT_RAND_GENERATING |
+ STARFIVE_STAT_RAND_SEEDING)),
+ 10, 100000);
+}
+
+static inline void starfive_trng_irq_mask_clear(struct starfive_trng *trng)
+{
+ /* clear register: ISTAT */
+ u32 data = readl(trng->base + STARFIVE_ISTAT);
+
+ writel(data, trng->base + STARFIVE_ISTAT);
+}
+
+static int starfive_trng_cmd(struct starfive_trng *trng, u32 cmd, bool wait)
+{
+ int wait_time = 1000;
+
+ /* allow up to 40 us for wait == 0 */
+ if (!wait)
+ wait_time = 40;
+
+ switch (cmd) {
+ case STARFIVE_CTRL_GENE_RANDNUM:
+ reinit_completion(&trng->random_done);
+ spin_lock_irq(&trng->write_lock);
+ writel(cmd, trng->base + STARFIVE_CTRL);
+ spin_unlock_irq(&trng->write_lock);
+ if (!wait_for_completion_timeout(&trng->random_done, usecs_to_jiffies(wait_time)))
+ return -ETIMEDOUT;
+ break;
+ case STARFIVE_CTRL_EXEC_RANDRESEED:
+ reinit_completion(&trng->reseed_done);
+ spin_lock_irq(&trng->write_lock);
+ writel(cmd, trng->base + STARFIVE_CTRL);
+ spin_unlock_irq(&trng->write_lock);
+ if (!wait_for_completion_timeout(&trng->reseed_done, usecs_to_jiffies(wait_time)))
+ return -ETIMEDOUT;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int starfive_trng_init(struct hwrng *rng)
+{
+ struct starfive_trng *trng = to_trng(rng);
+ u32 mode, intr = 0;
+
+ /* 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);
+
+ intr |= STARFIVE_IE_ALL;
+ writel(intr, trng->base + STARFIVE_IE);
+
+ mode = readl(trng->base + STARFIVE_MODE);
+
+ switch (trng->mode) {
+ case PRNG_128BIT:
+ mode &= ~STARFIVE_MODE_R256;
+ break;
+ case PRNG_256BIT:
+ mode |= STARFIVE_MODE_R256;
+ break;
+ default:
+ mode |= STARFIVE_MODE_R256;
+ break;
+ }
+
+ writel(mode, trng->base + STARFIVE_MODE);
+
+ return starfive_trng_cmd(trng, STARFIVE_CTRL_EXEC_RANDRESEED, 1);
+}
+
+static irqreturn_t starfive_trng_irq(int irq, void *priv)
+{
+ u32 status;
+ struct starfive_trng *trng = (struct starfive_trng *)priv;
+
+ status = readl(trng->base + STARFIVE_ISTAT);
+ 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) {
+ 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);
+ /* SEU occurred, reseeding required*/
+ spin_lock(&trng->write_lock);
+ writel(STARFIVE_CTRL_EXEC_RANDRESEED, trng->base + STARFIVE_CTRL);
+ spin_unlock(&trng->write_lock);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static void starfive_trng_cleanup(struct hwrng *rng)
+{
+ struct starfive_trng *trng = to_trng(rng);
+
+ writel(0, trng->base + STARFIVE_CTRL);
+
+ reset_control_assert(trng->rst);
+ clk_disable_unprepare(trng->hclk);
+ clk_disable_unprepare(trng->ahb);
+}
+
+static int starfive_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+ struct starfive_trng *trng = to_trng(rng);
+ int ret;
+
+ pm_runtime_get_sync(trng->dev);
+
+ if (trng->mode == PRNG_256BIT)
+ max = min_t(size_t, max, (STARFIVE_RAND_LEN * 8));
+ else
+ max = min_t(size_t, max, (STARFIVE_RAND_LEN * 4));
+
+ if (wait) {
+ ret = starfive_trng_wait_idle(trng);
+ if (ret)
+ return -ETIMEDOUT;
+ }
+
+ ret = starfive_trng_cmd(trng, STARFIVE_CTRL_GENE_RANDNUM, wait);
+ if (ret)
+ return ret;
+
+ memcpy_fromio(buf, trng->base + STARFIVE_RAND0, max);
+
+ pm_runtime_put_sync_autosuspend(trng->dev);
+
+ return max;
+}
+
+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);
+ if (!trng)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, trng);
+ trng->dev = &pdev->dev;
+
+ 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;
+
+ init_completion(&trng->random_done);
+ init_completion(&trng->reseed_done);
+ spin_lock_init(&trng->write_lock);
+
+ ret = devm_request_irq(&pdev->dev, irq, starfive_trng_irq, 0, pdev->name,
+ (void *)trng);
+ if (ret)
+ return dev_err_probe(&pdev->dev, irq,
+ "Failed to register interrupt handler\n");
+
+ trng->hclk = devm_clk_get(&pdev->dev, "hclk");
+ if (IS_ERR(trng->hclk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(trng->hclk),
+ "Error getting hardware reference clock\n");
+
+ trng->ahb = devm_clk_get(&pdev->dev, "ahb");
+ if (IS_ERR(trng->ahb))
+ return dev_err_probe(&pdev->dev, PTR_ERR(trng->ahb),
+ "Error getting ahb reference clock\n");
+
+ trng->rst = devm_reset_control_get_shared(&pdev->dev, NULL);
+ if (IS_ERR(trng->rst))
+ return dev_err_probe(&pdev->dev, PTR_ERR(trng->rst),
+ "Error getting hardware reset line\n");
+
+ clk_prepare_enable(trng->hclk);
+ clk_prepare_enable(trng->ahb);
+ reset_control_deassert(trng->rst);
+
+ trng->rng.name = dev_driver_string(&pdev->dev);
+ trng->rng.init = starfive_trng_init;
+ trng->rng.cleanup = starfive_trng_cleanup;
+ trng->rng.read = starfive_trng_read;
+
+ trng->mode = PRNG_256BIT;
+ trng->mission = 1;
+ trng->reseed = RANDOM_RESEED;
+
+ ret = devm_hwrng_register(&pdev->dev, &trng->rng);
+ if (ret) {
+ dev_err_probe(&pdev->dev, ret, "Failed to register hwrng\n");
+ goto err_fail_register;
+ }
+
+ pm_runtime_use_autosuspend(&pdev->dev);
+ pm_runtime_set_autosuspend_delay(&pdev->dev, 100);
+ pm_runtime_enable(&pdev->dev);
+
+ return 0;
+
+err_fail_register:
+ pm_runtime_disable(&pdev->dev);
+
+ reset_control_assert(trng->rst);
+ clk_disable_unprepare(trng->ahb);
+ clk_disable_unprepare(trng->hclk);
+
+ return ret;
+}
+
+static int __maybe_unused starfive_trng_suspend(struct device *dev)
+{
+ struct starfive_trng *trng = dev_get_drvdata(dev);
+
+ clk_disable_unprepare(trng->hclk);
+ clk_disable_unprepare(trng->ahb);
+
+ return 0;
+}
+
+static int __maybe_unused starfive_trng_resume(struct device *dev)
+{
+ struct starfive_trng *trng = dev_get_drvdata(dev);
+
+ clk_prepare_enable(trng->hclk);
+ clk_prepare_enable(trng->ahb);
+
+ return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(starfive_trng_pm_ops, starfive_trng_suspend,
+ starfive_trng_resume);
+
+static const struct of_device_id trng_dt_ids[] __maybe_unused = {
+ { .compatible = "starfive,jh7110-trng" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, trng_dt_ids);
+
+static struct platform_driver starfive_trng_driver = {
+ .probe = starfive_trng_probe,
+ .driver = {
+ .name = "starfive-trng",
+ .pm = &starfive_trng_pm_ops,
+ .of_match_table = of_match_ptr(trng_dt_ids),
+ },
+};
+
+module_platform_driver(starfive_trng_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("StarFive True Random Number Generator");
--
2.25.1
Adding StarFive TRNG controller node to VisionFive 2 SoC.
Co-developed-by: Jenny Zhang <[email protected]>
Signed-off-by: Jenny Zhang <[email protected]>
Signed-off-by: Jia Jie Ho <[email protected]>
---
arch/riscv/boot/dts/starfive/jh7110.dtsi | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/riscv/boot/dts/starfive/jh7110.dtsi b/arch/riscv/boot/dts/starfive/jh7110.dtsi
index 4ac159d79d66..3c29e0bc6246 100644
--- a/arch/riscv/boot/dts/starfive/jh7110.dtsi
+++ b/arch/riscv/boot/dts/starfive/jh7110.dtsi
@@ -455,5 +455,15 @@ uart5: serial@12020000 {
reg-shift = <2>;
status = "disabled";
};
+
+ rng: rng@1600c000 {
+ compatible = "starfive,jh7110-trng";
+ reg = <0x0 0x1600C000 0x0 0x4000>;
+ clocks = <&stgcrg JH7110_STGCLK_SEC_HCLK>,
+ <&stgcrg JH7110_STGCLK_SEC_MISCAHB>;
+ clock-names = "hclk", "ahb";
+ resets = <&stgcrg JH7110_STGRST_SEC_TOP_HRESETN>;
+ interrupts = <30>;
+ };
};
};
--
2.25.1
On Thu, Jan 12, 2023 at 12:38:11PM +0800, Jia Jie Ho wrote:
> This adds driver support for the hardware random number generator in
> Starfive SoCs and adds StarFive TRNG entry to MAINTAINERS.
>
> Co-developed-by: Jenny Zhang <[email protected]>
> Signed-off-by: Jenny Zhang <[email protected]>
> Signed-off-by: Jia Jie Ho <[email protected]>
> ---
> MAINTAINERS | 6 +
> drivers/char/hw_random/Kconfig | 11 +
> drivers/char/hw_random/Makefile | 1 +
> drivers/char/hw_random/starfive-trng.c | 397 +++++++++++++++++++++++++
> 4 files changed, 415 insertions(+)
> create mode 100644 drivers/char/hw_random/starfive-trng.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 65140500d9f8..b91e3fc11fc6 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -19626,6 +19626,12 @@ F: drivers/reset/reset-starfive.c
> F: include/linux/reset/starfive.h
> F: include/dt-bindings/reset/starfive*
>
> +STARFIVE TRNG DRIVER
> +M: Jia Jie Ho <[email protected]>
> +S: Maintained
> +F: Documentation/devicetree/bindings/rng/starfive*
> +F: drivers/char/hw_random/starfive-trng.c
minor nit (so don't submit another version just to fix this):
This should be Supported, no?
> diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
> index 3e948cf04476..f68ac370847f 100644
> --- a/drivers/char/hw_random/Makefile
> +++ b/drivers/char/hw_random/Makefile
> @@ -47,3 +47,4 @@ obj-$(CONFIG_HW_RANDOM_XIPHERA) += xiphera-trng.o
> obj-$(CONFIG_HW_RANDOM_ARM_SMCCC_TRNG) += arm_smccc_trng.o
> obj-$(CONFIG_HW_RANDOM_CN10K) += cn10k-rng.o
> obj-$(CONFIG_HW_RANDOM_POLARFIRE_SOC) += mpfs-rng.o
> +obj-$(CONFIG_HW_RANDOM_STARFIVE) += starfive-trng.o
Is "STARFIVE" a bit too general of a name here and in the Kconfig entry?
I don't have a TRM for the JH7100, but this name (and the Kconfig text)
would give me the impression that I can use it there too.
Does this driver support both?
> +static int starfive_trng_probe(struct platform_device *pdev)
> + clk_prepare_enable(trng->hclk);
> + clk_prepare_enable(trng->ahb);
> + reset_control_deassert(trng->rst);
> +
> + trng->rng.name = dev_driver_string(&pdev->dev);
> + trng->rng.init = starfive_trng_init;
> + trng->rng.cleanup = starfive_trng_cleanup;
> + trng->rng.read = starfive_trng_read;
> +
> + trng->mode = PRNG_256BIT;
> + trng->mission = 1;
> + trng->reseed = RANDOM_RESEED;
> +
> + ret = devm_hwrng_register(&pdev->dev, &trng->rng);
> + if (ret) {
> + dev_err_probe(&pdev->dev, ret, "Failed to register hwrng\n");
> + goto err_fail_register;
> + }
> +
> + pm_runtime_use_autosuspend(&pdev->dev);
> + pm_runtime_set_autosuspend_delay(&pdev->dev, 100);
> + pm_runtime_enable(&pdev->dev);
> +
> + return 0;
> +
> +err_fail_register:
> + pm_runtime_disable(&pdev->dev);
This was only enabled after the only goto for this label, does it
serve a purpose?
I know little about runtime PM, it just caught my eye.
I looked at the other rng drivers that had calls to pm_runtime_enable(),
but they all seem to do their pm enablement _before_ calling
hwrng_register().
Again, I am not familiar with runtime PM, but curious why you are doing
things differently, that's all.
> +
> + reset_control_assert(trng->rst);
> + clk_disable_unprepare(trng->ahb);
> + clk_disable_unprepare(trng->hclk);
> +
> + return ret;
> +}
Thanks,
Conor.
> > +STARFIVE TRNG DRIVER
> > +M: Jia Jie Ho <[email protected]>
> > +S: Maintained
> > +F: Documentation/devicetree/bindings/rng/starfive*
> > +F: drivers/char/hw_random/starfive-trng.c
>
> minor nit (so don't submit another version just to fix this):
> This should be Supported, no?
>
Hi Conor,
I'll update this in next version together with other comments below.
> > diff --git a/drivers/char/hw_random/Makefile
> > b/drivers/char/hw_random/Makefile index 3e948cf04476..f68ac370847f
> > 100644
> > --- a/drivers/char/hw_random/Makefile
> > +++ b/drivers/char/hw_random/Makefile
> > @@ -47,3 +47,4 @@ obj-$(CONFIG_HW_RANDOM_XIPHERA) += xiphera-
> trng.o
> > obj-$(CONFIG_HW_RANDOM_ARM_SMCCC_TRNG) += arm_smccc_trng.o
> > obj-$(CONFIG_HW_RANDOM_CN10K) += cn10k-rng.o
> > obj-$(CONFIG_HW_RANDOM_POLARFIRE_SOC) += mpfs-rng.o
> > +obj-$(CONFIG_HW_RANDOM_STARFIVE) += starfive-trng.o
>
> Is "STARFIVE" a bit too general of a name here and in the Kconfig entry?
> I don't have a TRM for the JH7100, but this name (and the Kconfig text)
> would give me the impression that I can use it there too.
> Does this driver support both?
>
7100 uses a different trng module but this same generator might be used in
future products, so I left it generic. Would it be better to specify the product?
> > +static int starfive_trng_probe(struct platform_device *pdev)
[...]
> > + ret = devm_hwrng_register(&pdev->dev, &trng->rng);
> > + if (ret) {
> > + dev_err_probe(&pdev->dev, ret, "Failed to register
> hwrng\n");
> > + goto err_fail_register;
> > + }
> > +
> > + pm_runtime_use_autosuspend(&pdev->dev);
> > + pm_runtime_set_autosuspend_delay(&pdev->dev, 100);
>
> > + pm_runtime_enable(&pdev->dev);
>
> > +
> > + return 0;
> > +
> > +err_fail_register:
>
> > + pm_runtime_disable(&pdev->dev);
>
> This was only enabled after the only goto for this label, does it serve a
> purpose?
> I know little about runtime PM, it just caught my eye.
> I looked at the other rng drivers that had calls to pm_runtime_enable(), but
> they all seem to do their pm enablement _before_ calling hwrng_register().
> Again, I am not familiar with runtime PM, but curious why you are doing
> things differently, that's all.
It does make more sense to move pm_runtime_enable before registering the
generator to align with codes in the goto label.
I'll fix this part.
Thanks again for reviewing the patches.
Best regards,
Jia Jie