x86: apl: Add PUNIT driver
Add a driver for the Apollo Lake P-unit (power unit). It is modelled as a
syscon driver since it only needs to be probed.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/cpu/apollolake/punit.c b/arch/x86/cpu/apollolake/punit.c
new file mode 100644
index 0000000..1a131fb
--- /dev/null
+++ b/arch/x86/cpu/apollolake/punit.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <spl.h>
+#include <asm/cpu.h>
+#include <asm/cpu_common.h>
+#include <asm/intel_regs.h>
+#include <asm/io.h>
+#include <asm/pci.h>
+#include <asm/arch/systemagent.h>
+
+/*
+ * Punit Initialisation code. This all isn't documented, but
+ * this is the recipe.
+ */
+static int punit_init(struct udevice *dev)
+{
+ struct udevice *cpu;
+ u32 reg;
+ ulong start;
+ int ret;
+
+ /* Thermal throttle activation offset */
+ ret = uclass_first_device_err(UCLASS_CPU, &cpu);
+ if (ret)
+ return log_msg_ret("Cannot find CPU", ret);
+ cpu_configure_thermal_target(cpu);
+
+ /*
+ * Software Core Disable Mask (P_CR_CORE_DISABLE_MASK_0_0_0_MCHBAR).
+ * Enable all cores here.
+ */
+ writel(0, MCHBAR_REG(CORE_DISABLE_MASK));
+
+ /* P-Unit bring up */
+ reg = readl(MCHBAR_REG(BIOS_RESET_CPL));
+ if (reg == 0xffffffff) {
+ /* P-unit not found */
+ debug("Punit MMIO not available\n");
+ return -ENOENT;
+ }
+
+ /* Set Punit interrupt pin IPIN offset 3D */
+ dm_pci_write_config8(dev, PCI_INTERRUPT_PIN, 0x2);
+
+ /* Set PUINT IRQ to 24 and INTPIN LOCK */
+ writel(PUINT_THERMAL_DEVICE_IRQ_VEC_NUMBER |
+ PUINT_THERMAL_DEVICE_IRQ_LOCK,
+ MCHBAR_REG(PUNIT_THERMAL_DEVICE_IRQ));
+
+ /* Stage0 BIOS Reset Complete (RST_CPL) */
+ enable_bios_reset_cpl();
+
+ /*
+ * Poll for bit 8 to check if PCODE has completed its action in response
+ * to BIOS Reset complete. We wait here till 1 ms for the bit to get
+ * set.
+ */
+ start = get_timer(0);
+ while (!(readl(MCHBAR_REG(BIOS_RESET_CPL)) & PCODE_INIT_DONE)) {
+ if (get_timer(start) > 1) {
+ debug("PCODE Init Done timeout\n");
+ return -ETIMEDOUT;
+ }
+ udelay(100);
+ }
+ debug("PUNIT init complete\n");
+
+ return 0;
+}
+
+static int apl_punit_probe(struct udevice *dev)
+{
+ if (spl_phase() == PHASE_SPL)
+ return punit_init(dev);
+
+ return 0;
+}
+
+static const struct udevice_id apl_syscon_ids[] = {
+ { .compatible = "intel,apl-punit", .data = X86_SYSCON_PUNIT },
+ { }
+};
+
+U_BOOT_DRIVER(syscon_intel_punit) = {
+ .name = "intel_punit_syscon",
+ .id = UCLASS_SYSCON,
+ .of_match = apl_syscon_ids,
+ .probe = apl_punit_probe,
+};