lpss.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <device/mmio.h>
#include <device/pci_def.h>
#include <device/pci_ops.h>
#include <intelblocks/lpss.h>
 
/* Clock register */
#define LPSS_CLOCK_CTL_REG      0x200
#define LPSS_CNT_CLOCK_EN       1
#define LPSS_CNT_CLK_UPDATE     (1 << 31)
#define LPSS_CLOCK_DIV_N(n)     (((n) & 0x7fff) << 16)
#define LPSS_CLOCK_DIV_M(m)     (((m) & 0x7fff) << 1)
 
/* reset register  */
#define 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)
 */
 
#define LPSS_CNT_RST_RELEASE    3
 
/* DMA Software Reset Control */
#define LPSS_DMA_RST_RELEASE    (1 << 2)
 
/* Power management control and status register */
#define PME_CTRL_STATUS 0x84
/* Bit 1:0 Powerstate, controls D0 and D3 state */
#define POWER_STATE_MASK        3
 
bool lpss_is_controller_in_reset(uintptr_t base)
{
        uint8_t *addr = (void *)base;
        uint32_t val = read32(addr + LPSS_RESET_CTL_REG);
 
        if (val == 0xFFFFFFFF)
                return true;
 
        return !(val & LPSS_CNT_RST_RELEASE);
}
 
void lpss_reset_release(uintptr_t base)
{
        uint8_t *addr = (void *)base;
 
        /* Take controller out of reset */
        write32(addr + LPSS_RESET_CTL_REG, LPSS_CNT_RST_RELEASE);
}
 
void lpss_clk_update(uintptr_t base, uint32_t clk_m_val, uint32_t clk_n_val)
{
        uint8_t *addr = (void *)base;
        uint32_t clk_sel;
 
        addr += LPSS_CLOCK_CTL_REG;
        clk_sel = LPSS_CLOCK_DIV_N(clk_n_val) | LPSS_CLOCK_DIV_M(clk_m_val);
        clk_sel |= LPSS_CNT_CLK_UPDATE | LPSS_CNT_CLOCK_EN;
 
        write32(addr, clk_sel);
}
 
/* Set controller power state to D0 or D3 */
void lpss_set_power_state(pci_devfn_t devfn, enum lpss_pwr_state state)
{
        uint8_t reg8 = pci_s_read_config8(devfn, PME_CTRL_STATUS);
        reg8 &= ~POWER_STATE_MASK;
        reg8 |= state;
        pci_s_write_config8(devfn, PME_CTRL_STATUS, reg8);
}