From 01c35f269f21398fa9d1db1b90b73f7e95a3bf22 Mon Sep 17 00:00:00 2001
From: Claudiu Beznea <claudiu.beznea@microchip.com>
Date: Thu, 1 Oct 2020 13:27:25 +0300
Subject: [PATCH] cpu: at91: add driver for CPU

Add basic CPU driver use to retrieve information about CPU itself.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
 MAINTAINERS            |   1 +
 drivers/cpu/Makefile   |   1 +
 drivers/cpu/at91_cpu.c | 123 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 125 insertions(+)
 create mode 100644 drivers/cpu/at91_cpu.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 85e51855c4..91b06b49bd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -291,6 +291,7 @@ S:	Maintained
 T:	git https://gitlab.denx.de/u-boot/custodians/u-boot-atmel.git
 F:	arch/arm/mach-at91/
 F:	board/atmel/
+F:	drivers/cpu/at91_cpu.c
 F:	drivers/misc/microchip_flexcom.c
 F:	drivers/timer/mchp-pit64b-timer.c
 
diff --git a/drivers/cpu/Makefile b/drivers/cpu/Makefile
index 0b5dbc7c88..c8532637ca 100644
--- a/drivers/cpu/Makefile
+++ b/drivers/cpu/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_CPU) += cpu-uclass.o
 
 obj-$(CONFIG_ARCH_BMIPS) += bmips_cpu.o
 obj-$(CONFIG_ARCH_IMX8) += imx8_cpu.o
+obj-$(CONFIG_ARCH_AT91) += at91_cpu.o
 obj-$(CONFIG_CPU_MPC83XX) += mpc83xx_cpu.o
 obj-$(CONFIG_CPU_RISCV) += riscv_cpu.o
 obj-$(CONFIG_SANDBOX) += cpu_sandbox.o
diff --git a/drivers/cpu/at91_cpu.c b/drivers/cpu/at91_cpu.c
new file mode 100644
index 0000000000..058ae3a811
--- /dev/null
+++ b/drivers/cpu/at91_cpu.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020 Microchip Technology Inc. and its subsidiaries
+ *
+ * Author: Claudiu Beznea <claudiu.beznea@microchip.com>
+ */
+
+#include <common.h>
+#include <cpu.h>
+#include <dm.h>
+#include <div64.h>
+#include <linux/clk-provider.h>
+
+struct at91_cpu_platdata {
+	const char *name;
+	ulong cpufreq_mhz;
+	ulong mckfreq_mhz;
+	ulong xtalfreq_mhz;
+};
+
+extern char *get_cpu_name(void);
+
+const char *at91_cpu_get_name(void)
+{
+	return get_cpu_name();
+}
+
+int at91_cpu_get_desc(const struct udevice *dev, char *buf, int size)
+{
+	struct at91_cpu_platdata *plat = dev_get_platdata(dev);
+
+	snprintf(buf, size, "%s\n"
+		 "Crystal frequency: %8lu MHz\n"
+		 "CPU clock        : %8lu MHz\n"
+		 "Master clock     : %8lu MHz\n",
+		 plat->name, plat->xtalfreq_mhz, plat->cpufreq_mhz,
+		 plat->mckfreq_mhz);
+
+	return 0;
+}
+
+static int at91_cpu_get_info(const struct udevice *dev, struct cpu_info *info)
+{
+	struct at91_cpu_platdata *plat = dev_get_platdata(dev);
+
+	info->cpu_freq = plat->cpufreq_mhz * 1000000;
+	info->features = BIT(CPU_FEAT_L1_CACHE);
+
+	return 0;
+}
+
+static int at91_cpu_get_count(const struct udevice *dev)
+{
+	return 1;
+}
+
+static int at91_cpu_get_vendor(const struct udevice *dev,  char *buf, int size)
+{
+	snprintf(buf, size, "Microchip Technology Inc.");
+
+	return 0;
+}
+
+static const struct cpu_ops at91_cpu_ops = {
+	.get_desc	= at91_cpu_get_desc,
+	.get_info	= at91_cpu_get_info,
+	.get_count	= at91_cpu_get_count,
+	.get_vendor	= at91_cpu_get_vendor,
+};
+
+static const struct udevice_id at91_cpu_ids[] = {
+	{ .compatible = "arm,cortex-a7" },
+	{ /* Sentinel. */ }
+};
+
+static int at91_cpu_probe(struct udevice *dev)
+{
+	struct at91_cpu_platdata *plat = dev_get_platdata(dev);
+	struct clk clk;
+	ulong rate;
+	int ret;
+
+	ret = clk_get_by_index(dev, 0, &clk);
+	if (ret)
+		return ret;
+
+	rate  = clk_get_rate(&clk);
+	if (!rate)
+		return -ENOTSUPP;
+	plat->cpufreq_mhz = DIV_ROUND_CLOSEST_ULL(rate, 1000000);
+
+	ret = clk_get_by_index(dev, 1, &clk);
+	if (ret)
+		return ret;
+
+	rate = clk_get_rate(&clk);
+	if (!rate)
+		return -ENOTSUPP;
+	plat->mckfreq_mhz = DIV_ROUND_CLOSEST_ULL(rate, 1000000);
+
+	ret = clk_get_by_index(dev, 2, &clk);
+	if (ret)
+		return ret;
+
+	rate = clk_get_rate(&clk);
+	if (!rate)
+		return -ENOTSUPP;
+	plat->xtalfreq_mhz = DIV_ROUND_CLOSEST_ULL(rate, 1000000);
+
+	plat->name = get_cpu_name();
+
+	return 0;
+}
+
+U_BOOT_DRIVER(cpu_at91_drv) = {
+	.name		= "at91-cpu",
+	.id		= UCLASS_CPU,
+	.of_match	= at91_cpu_ids,
+	.ops		= &at91_cpu_ops,
+	.probe		= at91_cpu_probe,
+	.platdata_auto_alloc_size = sizeof(struct at91_cpu_platdata),
+	.flags		= DM_FLAG_PRE_RELOC,
+};