This subsystem is present on various Intel SoCs.
Add very basic support for taking an lpss device out of reset.
Signed-off-by: Simon Glass sjg@chromium.org
---
Changes in v4: - Add support for updating power state - Move this to intel_common
Changes in v3: None Changes in v2: None
arch/x86/cpu/intel_common/Makefile | 1 + arch/x86/cpu/intel_common/lpss.c | 44 ++++++++++++++++++++++++++++++ arch/x86/include/asm/lpss.h | 36 ++++++++++++++++++++++++ 3 files changed, 81 insertions(+) create mode 100644 arch/x86/cpu/intel_common/lpss.c create mode 100644 arch/x86/include/asm/lpss.h
diff --git a/arch/x86/cpu/intel_common/Makefile b/arch/x86/cpu/intel_common/Makefile index 09212cee04..cc4e1c962b 100644 --- a/arch/x86/cpu/intel_common/Makefile +++ b/arch/x86/cpu/intel_common/Makefile @@ -19,6 +19,7 @@ endif obj-y += cpu.o obj-y += fast_spi.o obj-y += lpc.o +obj-y += lpss.o ifndef CONFIG_TARGET_EFI_APP obj-$(CONFIG_$(SPL_TPL_)X86_32BIT_INIT) += microcode.o ifndef CONFIG_$(SPL_)X86_64 diff --git a/arch/x86/cpu/intel_common/lpss.c b/arch/x86/cpu/intel_common/lpss.c new file mode 100644 index 0000000000..26a2d2d1e3 --- /dev/null +++ b/arch/x86/cpu/intel_common/lpss.c @@ -0,0 +1,44 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Special driver to handle of-platdata + * + * Copyright 2019 Google LLC + * + * Some code from coreboot lpss.c + */ + +#include <common.h> +#include <dm.h> +#include <pci.h> +#include <asm/io.h> +#include <asm/lpss.h> + +enum { + LPSS_RESET_CTL_REG = 0x204, + + /* + * Bit 1:0 controls LPSS controller reset. + * + * 00 ->LPSS Host Controller is in reset (Reset Asserted) + * 01/10 ->Reserved + * 11 ->LPSS Host Controller is NOT at reset (Reset Released) + */ + LPSS_CNT_RST_RELEASE = 3, + + /* Power management control and status register */ + PME_CTRL_STATUS = 0x84, + + /* Bit 1:0 Powerstate, controls D0 and D3 state */ + POWER_STATE_MASK = 3, +}; + +/* Take controller out of reset */ +void lpss_reset_release(void *regs) +{ + writel(LPSS_CNT_RST_RELEASE, regs + LPSS_RESET_CTL_REG); +} + +void lpss_set_power_state(struct udevice *dev, enum lpss_pwr_state state) +{ + dm_pci_clrset_config8(dev, PME_CTRL_STATUS, POWER_STATE_MASK, state); +} diff --git a/arch/x86/include/asm/lpss.h b/arch/x86/include/asm/lpss.h new file mode 100644 index 0000000000..7814872688 --- /dev/null +++ b/arch/x86/include/asm/lpss.h @@ -0,0 +1,36 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright 2019 Google LLC + */ + +#ifndef __ASM_LPSS_H +#define __ASM_LPSS_H + +struct udevice; + +/* D0 and D3 enable config */ +enum lpss_pwr_state { + STATE_D0 = 0, + STATE_D3 = 3 +}; + +/** + * lpss_reset_release() - Release device from reset + * + * This is used for devices which have LPSS support. + * + * @regs: Pointer to device registers + */ +void lpss_reset_release(void *regs); + +/** + * lpss_set_power_state() - Change power state of a device + * + * This is used for devices which have LPSS support. + * + * @dev: Device to update + * @state: New power state to set + */ +void lpss_set_power_state(struct udevice *dev, enum lpss_pwr_state state); + +#endif