[RFC PATCH v3 3/9] accel: rocket: Add RK3568 SoC support

[Midgy BALON]

The RK3568 has a single core of the same NVDLA-derived NPU IP as the
RK3588, with a 32-bit AXI master.  Unlike the RK3588 it must be powered
on and de-idled through the PMU, and its PVTPLL clock started via SCMI,
before the NPU is reachable.  Add rk3568_soc_data with an noc_init
callback performing this bring-up.

Signed-off-by: Midgy BALON <midgy971 at gmail.com>
---
 drivers/accel/rocket/rocket_core.c |  9 +++++
 drivers/accel/rocket/rocket_core.h |  3 ++
 drivers/accel/rocket/rocket_drv.c  | 53 ++++++++++++++++++++++++++++++
 3 files changed, 65 insertions(+)

diff --git a/drivers/accel/rocket/rocket_core.c b/drivers/accel/rocket/rocket_core.c
index 09c445af7de73..a8de876365873 100644
--- a/drivers/accel/rocket/rocket_core.c
+++ b/drivers/accel/rocket/rocket_core.c
@@ -88,6 +88,15 @@ int rocket_core_init(struct rocket_core *core)
 		return err;
 	}
 
+	if (core->soc_data->noc_init) {
+		err = core->soc_data->noc_init(core);
+		if (err) {
+			pm_runtime_put_sync(dev);
+			rocket_job_fini(core);
+			return err;
+		}
+	}
+
 	version = rocket_pc_readl(core, VERSION);
 	version += rocket_pc_readl(core, VERSION_NUM) & 0xffff;
 
diff --git a/drivers/accel/rocket/rocket_core.h b/drivers/accel/rocket/rocket_core.h
index d6421251670dc..66d138a8ed773 100644
--- a/drivers/accel/rocket/rocket_core.h
+++ b/drivers/accel/rocket/rocket_core.h
@@ -18,10 +18,13 @@ struct rocket_core;
  * struct rocket_soc_data - per-SoC configuration data
  * @num_cores: Number of NPU cores in this SoC.
  * @dma_bits: Physical address width reachable by the NPU's AXI master.
+ * @noc_init: Optional callback to power on and de-idle the NPU NOC bus.
+ *            Required on RK3568, where this is done through the PMU.
  */
 struct rocket_soc_data {
 	unsigned int num_cores;
 	unsigned int dma_bits;
+	int (*noc_init)(struct rocket_core *core);
 };
 
 #define rocket_pc_readl(core, reg) \
diff --git a/drivers/accel/rocket/rocket_drv.c b/drivers/accel/rocket/rocket_drv.c
index c18840e5aff76..5a72d0b5f4dff 100644
--- a/drivers/accel/rocket/rocket_drv.c
+++ b/drivers/accel/rocket/rocket_drv.c
@@ -9,9 +9,11 @@
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/iommu.h>
+#include <linux/mfd/syscon.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/regmap.h>
 
 #include "rocket_device.h"
 #include "rocket_drv.h"
@@ -217,12 +219,63 @@ static void rocket_remove(struct platform_device *pdev)
 	}
 }
 
+/*
+ * On RK3568 the NPU NOC bus is gated and idle out of reset and must be
+ * powered on and de-idled through the PMU before the NPU is reachable.  PMU
+ * registers use a write-mask protocol: the upper 16 bits enable writes to the
+ * matching lower 16 bits.
+ *
+ * The NPU's high-speed clock is a PVTPLL managed by TF-A via SCMI and must be
+ * running before the NOC acknowledges the de-idle request.  Force a real SCMI
+ * rate change (an intermediate rate defeats the clock framework's
+ * unchanged-rate shortcut) now that the power domain is on and clocks enabled.
+ */
+#define ROCKET_RK3568_SCMI_CLK	2
+
+static int rk3568_noc_init(struct rocket_core *core)
+{
+	struct regmap *pmu;
+	unsigned int val;
+	int ret;
+
+	clk_set_rate(core->clks[ROCKET_RK3568_SCMI_CLK].clk, 600000000UL);
+	clk_set_rate(core->clks[ROCKET_RK3568_SCMI_CLK].clk, 1000000000UL);
+
+	pmu = syscon_regmap_lookup_by_phandle(core->dev->of_node, "rockchip,pmu");
+	if (IS_ERR(pmu))
+		return dev_err_probe(core->dev, PTR_ERR(pmu),
+				     "failed to get PMU regmap\n");
+
+	/* Power on the NPU power domain (PWR_GATE_SFTCON bit 1 = 0). */
+	regmap_write(pmu, 0xa0, BIT(1 + 16));
+
+	/* Disable NPU NOC auto-idle (NOC_AUTO_CON0 bit 2). */
+	regmap_write(pmu, 0x70, BIT(2 + 16));
+
+	/* Request NPU bus de-idle (BUS_IDLE_SFTCON0 bit 2 = 0). */
+	regmap_write(pmu, 0x50, BIT(2 + 16));
+
+	/* Wait for the bus to report active (BUS_IDLE_ST bit 2 = 0). */
+	ret = regmap_read_poll_timeout(pmu, 0x68, val, !(val & BIT(2)), 10, 1000);
+	if (ret)
+		dev_err(core->dev, "timed out waiting for NPU bus de-idle\n");
+
+	return ret;
+}
+
+static const struct rocket_soc_data rk3568_soc_data = {
+	.num_cores = 1,
+	.dma_bits = 32,
+	.noc_init = rk3568_noc_init,
+};
+
 static const struct rocket_soc_data rk3588_soc_data = {
 	.num_cores = 3,
 	.dma_bits = 40,
 };
 
 static const struct of_device_id dt_match[] = {
+	{ .compatible = "rockchip,rk3568-rknn-core", .data = &rk3568_soc_data },
 	{ .compatible = "rockchip,rk3588-rknn-core", .data = &rk3588_soc_data },
 	{}
 };
-- 
2.39.5