/*
 * Copyright (c) 2010-2012, NVIDIA Corporation. All rights reserved.
 * Copyright (c) 2011, Google, Inc.
 *
 * Author: Colin Cross <ccross@android.com>
 *         Gary King <gking@nvidia.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/linkage.h>

#include <soc/tegra/flowctrl.h>

#include <asm/assembler.h>
#include <asm/proc-fns.h>
#include <asm/cp15.h>
#include <asm/cache.h>

#include "irammap.h"
#include "sleep.h"

#define EMC_CFG                         0xc
#define EMC_ADR_CFG                     0x10
#define EMC_REFRESH                     0x70
#define EMC_NOP                         0xdc
#define EMC_SELF_REF                    0xe0
#define EMC_REQ_CTRL                    0x2b0
#define EMC_EMC_STATUS                  0x2b4

#define CLK_RESET_CCLK_BURST            0x20
#define CLK_RESET_CCLK_DIVIDER          0x24
#define CLK_RESET_SCLK_BURST            0x28
#define CLK_RESET_SCLK_DIVIDER          0x2c
#define CLK_RESET_PLLC_BASE             0x80
#define CLK_RESET_PLLM_BASE             0x90
#define CLK_RESET_PLLP_BASE             0xa0

#define APB_MISC_XM2CFGCPADCTRL         0x8c8
#define APB_MISC_XM2CFGDPADCTRL         0x8cc
#define APB_MISC_XM2CLKCFGPADCTRL       0x8d0
#define APB_MISC_XM2COMPPADCTRL         0x8d4
#define APB_MISC_XM2VTTGENPADCTRL       0x8d8
#define APB_MISC_XM2CFGCPADCTRL2        0x8e4
#define APB_MISC_XM2CFGDPADCTRL2        0x8e8

.macro pll_enable, rd, r_car_base, pll_base
        ldr     \rd, [\r_car_base, #\pll_base]
        tst     \rd, #(1 << 30)
        orreq   \rd, \rd, #(1 << 30)
        streq   \rd, [\r_car_base, #\pll_base]
.endm

.macro emc_device_mask, rd, base
        ldr     \rd, [\base, #EMC_ADR_CFG]
        tst     \rd, #(0x3 << 24)
        moveq   \rd, #(0x1 << 8)                @ just 1 device
        movne   \rd, #(0x3 << 8)                @ 2 devices
.endm

#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_PM_SLEEP)
/*
 * tegra20_hotplug_shutdown(void)
 *
 * puts the current cpu in reset
 * should never return
 */
ENTRY(tegra20_hotplug_shutdown)
        /* Put this CPU down */
        cpu_id  r0
        bl      tegra20_cpu_shutdown
        ret     lr                      @ should never get here
ENDPROC(tegra20_hotplug_shutdown)

/*
 * tegra20_cpu_shutdown(int cpu)
 *
 * r0 is cpu to reset
 *
 * puts the specified CPU in wait-for-event mode on the flow controller
 * and puts the CPU in reset
 * can be called on the current cpu or another cpu
 * if called on the current cpu, does not return
 * MUST NOT BE CALLED FOR CPU 0.
 *
 * corrupts r0-r3, r12
 */
ENTRY(tegra20_cpu_shutdown)
        cmp     r0, #0
        reteq   lr                      @ must not be called for CPU 0
        mov32   r1, TEGRA_IRAM_RESET_BASE_VIRT
        ldr     r2, =__tegra20_cpu1_resettable_status_offset
        mov     r12, #CPU_RESETTABLE
        strb    r12, [r1, r2]

        cpu_to_halt_reg r1, r0
        ldr     r3, =TEGRA_FLOW_CTRL_VIRT
        mov     r2, #FLOW_CTRL_WAITEVENT | FLOW_CTRL_JTAG_RESUME
        str     r2, [r3, r1]            @ put flow controller in wait event mode
        ldr     r2, [r3, r1]
        isb
        dsb
        movw    r1, 0x1011
        mov     r1, r1, lsl r0
        ldr     r3, =TEGRA_CLK_RESET_VIRT
        str     r1, [r3, #0x340]        @ put slave CPU in reset
        isb
        dsb
        cpu_id  r3
        cmp     r3, r0
        beq     .
        ret     lr
ENDPROC(tegra20_cpu_shutdown)
#endif

#ifdef CONFIG_PM_SLEEP
/*
 * tegra_pen_lock
 *
 * spinlock implementation with no atomic test-and-set and no coherence
 * using Peterson's algorithm on strongly-ordered registers
 * used to synchronize a cpu waking up from wfi with entering lp2 on idle
 *
 * The reference link of Peterson's algorithm:
 * http://en.wikipedia.org/wiki/Peterson's_algorithm
 *
 * SCRATCH37 = r1 = !turn (inverted from Peterson's algorithm)
 * on cpu 0:
 * r2 = flag[0] (in SCRATCH38)
 * r3 = flag[1] (in SCRATCH39)
 * on cpu1:
 * r2 = flag[1] (in SCRATCH39)
 * r3 = flag[0] (in SCRATCH38)
 *
 * must be called with MMU on
 * corrupts r0-r3, r12
 */
ENTRY(tegra_pen_lock)
        mov32   r3, TEGRA_PMC_VIRT
        cpu_id  r0
        add     r1, r3, #PMC_SCRATCH37
        cmp     r0, #0
        addeq   r2, r3, #PMC_SCRATCH38
        addeq   r3, r3, #PMC_SCRATCH39
        addne   r2, r3, #PMC_SCRATCH39
        addne   r3, r3, #PMC_SCRATCH38

        mov     r12, #1
        str     r12, [r2]               @ flag[cpu] = 1
        dsb
        str     r12, [r1]               @ !turn = cpu
1:      dsb
        ldr     r12, [r3]
        cmp     r12, #1                 @ flag[!cpu] == 1?
        ldreq   r12, [r1]
        cmpeq   r12, r0                 @ !turn == cpu?
        beq     1b                      @ while !turn == cpu && flag[!cpu] == 1

        ret     lr                      @ locked
ENDPROC(tegra_pen_lock)

ENTRY(tegra_pen_unlock)
        dsb
        mov32   r3, TEGRA_PMC_VIRT
        cpu_id  r0
        cmp     r0, #0
        addeq   r2, r3, #PMC_SCRATCH38
        addne   r2, r3, #PMC_SCRATCH39
        mov     r12, #0
        str     r12, [r2]
        ret     lr
ENDPROC(tegra_pen_unlock)

/*
 * tegra20_cpu_clear_resettable(void)
 *
 * Called to clear the "resettable soon" flag in IRAM variable when
 * it is expected that the secondary CPU will be idle soon.
 */
ENTRY(tegra20_cpu_clear_resettable)
        mov32   r1, TEGRA_IRAM_RESET_BASE_VIRT
        ldr     r2, =__tegra20_cpu1_resettable_status_offset
        mov     r12, #CPU_NOT_RESETTABLE
        strb    r12, [r1, r2]
        ret     lr
ENDPROC(tegra20_cpu_clear_resettable)

/*
 * tegra20_cpu_set_resettable_soon(void)
 *
 * Called to set the "resettable soon" flag in IRAM variable when
 * it is expected that the secondary CPU will be idle soon.
 */
ENTRY(tegra20_cpu_set_resettable_soon)
        mov32   r1, TEGRA_IRAM_RESET_BASE_VIRT
        ldr     r2, =__tegra20_cpu1_resettable_status_offset
        mov     r12, #CPU_RESETTABLE_SOON
        strb    r12, [r1, r2]
        ret     lr
ENDPROC(tegra20_cpu_set_resettable_soon)

/*
 * tegra20_cpu_is_resettable_soon(void)
 *
 * Returns true if the "resettable soon" flag in IRAM variable has been
 * set because it is expected that the secondary CPU will be idle soon.
 */
ENTRY(tegra20_cpu_is_resettable_soon)
        mov32   r1, TEGRA_IRAM_RESET_BASE_VIRT
        ldr     r2, =__tegra20_cpu1_resettable_status_offset
        ldrb    r12, [r1, r2]
        cmp     r12, #CPU_RESETTABLE_SOON
        moveq   r0, #1
        movne   r0, #0
        ret     lr
ENDPROC(tegra20_cpu_is_resettable_soon)

/*
 * tegra20_sleep_core_finish(unsigned long v2p)
 *
 * Enters suspend in LP0 or LP1 by turning off the mmu and jumping to
 * tegra20_tear_down_core in IRAM
 */
ENTRY(tegra20_sleep_core_finish)
        mov     r4, r0
        /* Flush, disable the L1 data cache and exit SMP */
        mov     r0, #TEGRA_FLUSH_CACHE_ALL
        bl      tegra_disable_clean_inv_dcache
        mov     r0, r4

        mov32   r3, tegra_shut_off_mmu
        add     r3, r3, r0

        mov32   r0, tegra20_tear_down_core
        mov32   r1, tegra20_iram_start
        sub     r0, r0, r1
        mov32   r1, TEGRA_IRAM_LPx_RESUME_AREA
        add     r0, r0, r1

        ret     r3
ENDPROC(tegra20_sleep_core_finish)

/*
 * tegra20_sleep_cpu_secondary_finish(unsigned long v2p)
 *
 * Enters WFI on secondary CPU by exiting coherency.
 */
ENTRY(tegra20_sleep_cpu_secondary_finish)
        stmfd   sp!, {r4-r11, lr}

        mrc     p15, 0, r11, c1, c0, 1  @ save actlr before exiting coherency

        /* Flush and disable the L1 data cache */
        mov     r0, #TEGRA_FLUSH_CACHE_LOUIS
        bl      tegra_disable_clean_inv_dcache

        mov32   r0, TEGRA_IRAM_RESET_BASE_VIRT
        ldr     r4, =__tegra20_cpu1_resettable_status_offset
        mov     r3, #CPU_RESETTABLE
        strb    r3, [r0, r4]

        bl      tegra_cpu_do_idle

        /*
         * cpu may be reset while in wfi, which will return through
         * tegra_resume to cpu_resume
         * or interrupt may wake wfi, which will return here
         * cpu state is unchanged - MMU is on, cache is on, coherency
         * is off, and the data cache is off
         *
         * r11 contains the original actlr
         */

        bl      tegra_pen_lock

        mov32   r0, TEGRA_IRAM_RESET_BASE_VIRT
        ldr     r4, =__tegra20_cpu1_resettable_status_offset
        mov     r3, #CPU_NOT_RESETTABLE
        strb    r3, [r0, r4]

        bl      tegra_pen_unlock

        /* Re-enable the data cache */
        mrc     p15, 0, r10, c1, c0, 0
        orr     r10, r10, #CR_C
        mcr     p15, 0, r10, c1, c0, 0
        isb

        mcr     p15, 0, r11, c1, c0, 1  @ reenable coherency

        /* Invalidate the TLBs & BTAC */
        mov     r1, #0
        mcr     p15, 0, r1, c8, c3, 0   @ invalidate shared TLBs
        mcr     p15, 0, r1, c7, c1, 6   @ invalidate shared BTAC
        dsb
        isb

        /* the cpu was running with coherency disabled,
         * caches may be out of date */
        bl      v7_flush_kern_cache_louis

        ldmfd   sp!, {r4 - r11, pc}
ENDPROC(tegra20_sleep_cpu_secondary_finish)

/*
 * tegra20_tear_down_cpu
 *
 * Switches the CPU cluster to PLL-P and enters sleep.
 */
ENTRY(tegra20_tear_down_cpu)
        bl      tegra_switch_cpu_to_pllp
        b       tegra20_enter_sleep
ENDPROC(tegra20_tear_down_cpu)

/* START OF ROUTINES COPIED TO IRAM */
        .align L1_CACHE_SHIFT
        .globl tegra20_iram_start
tegra20_iram_start:

/*
 * tegra20_lp1_reset
 *
 * reset vector for LP1 restore; copied into IRAM during suspend.
 * Brings the system back up to a safe staring point (SDRAM out of
 * self-refresh, PLLC, PLLM and PLLP reenabled, CPU running on PLLP,
 * system clock running on the same PLL that it suspended at), and
 * jumps to tegra_resume to restore virtual addressing and PLLX.
 * The physical address of tegra_resume expected to be stored in
 * PMC_SCRATCH41.
 *
 * NOTE: THIS *MUST* BE RELOCATED TO TEGRA_IRAM_LPx_RESUME_AREA.
 */
ENTRY(tegra20_lp1_reset)
        /*
         * The CPU and system bus are running at 32KHz and executing from
         * IRAM when this code is executed; immediately switch to CLKM and
         * enable PLLM, PLLP, PLLC.
         */
        mov32   r0, TEGRA_CLK_RESET_BASE

        mov     r1, #(1 << 28)
        str     r1, [r0, #CLK_RESET_SCLK_BURST]
        str     r1, [r0, #CLK_RESET_CCLK_BURST]
        mov     r1, #0
        str     r1, [r0, #CLK_RESET_CCLK_DIVIDER]
        str     r1, [r0, #CLK_RESET_SCLK_DIVIDER]

        pll_enable r1, r0, CLK_RESET_PLLM_BASE
        pll_enable r1, r0, CLK_RESET_PLLP_BASE
        pll_enable r1, r0, CLK_RESET_PLLC_BASE

        adr     r2, tegra20_sdram_pad_address
        adr     r4, tegra20_sdram_pad_save
        mov     r5, #0

        ldr     r6, tegra20_sdram_pad_size
padload:
        ldr     r7, [r2, r5]            @ r7 is the addr in the pad_address

        ldr     r1, [r4, r5]
        str     r1, [r7]                @ restore the value in pad_save

        add     r5, r5, #4
        cmp     r6, r5
        bne     padload

padload_done:
        /* 255uS delay for PLL stabilization */
        mov32   r7, TEGRA_TMRUS_BASE
        ldr     r1, [r7]
        add     r1, r1, #0xff
        wait_until r1, r7, r9

        adr     r4, tegra20_sclk_save
        ldr     r4, [r4]
        str     r4, [r0, #CLK_RESET_SCLK_BURST]
        mov32   r4, ((1 << 28) | (4))   @ burst policy is PLLP
        str     r4, [r0, #CLK_RESET_CCLK_BURST]

        mov32   r0, TEGRA_EMC_BASE
        ldr     r1, [r0, #EMC_CFG]
        bic     r1, r1, #(1 << 31)      @ disable DRAM_CLK_STOP
        str     r1, [r0, #EMC_CFG]

        mov     r1, #0
        str     r1, [r0, #EMC_SELF_REF] @ take DRAM out of self refresh
        mov     r1, #1
        str     r1, [r0, #EMC_NOP]
        str     r1, [r0, #EMC_NOP]
        str     r1, [r0, #EMC_REFRESH]

        emc_device_mask r1, r0

exit_selfrefresh_loop:
        ldr     r2, [r0, #EMC_EMC_STATUS]
        ands    r2, r2, r1
        bne     exit_selfrefresh_loop

        mov     r1, #0                  @ unstall all transactions
        str     r1, [r0, #EMC_REQ_CTRL]

        mov32   r0, TEGRA_PMC_BASE
        ldr     r0, [r0, #PMC_SCRATCH41]
        ret     r0                      @ jump to tegra_resume
ENDPROC(tegra20_lp1_reset)

/*
 * tegra20_tear_down_core
 *
 * copied into and executed from IRAM
 * puts memory in self-refresh for LP0 and LP1
 */
tegra20_tear_down_core:
        bl      tegra20_sdram_self_refresh
        bl      tegra20_switch_cpu_to_clk32k
        b       tegra20_enter_sleep

/*
 * tegra20_switch_cpu_to_clk32k
 *
 * In LP0 and LP1 all PLLs will be turned off. Switch the CPU and system clock
 * to the 32KHz clock.
 */
tegra20_switch_cpu_to_clk32k:
        /*
         * start by switching to CLKM to safely disable PLLs, then switch to
         * CLKS.
         */
        mov     r0, #(1 << 28)
        str     r0, [r5, #CLK_RESET_SCLK_BURST]
        str     r0, [r5, #CLK_RESET_CCLK_BURST]
        mov     r0, #0
        str     r0, [r5, #CLK_RESET_CCLK_DIVIDER]
        str     r0, [r5, #CLK_RESET_SCLK_DIVIDER]

        /* 2uS delay delay between changing SCLK and disabling PLLs */
        mov32   r7, TEGRA_TMRUS_BASE
        ldr     r1, [r7]
        add     r1, r1, #2
        wait_until r1, r7, r9

        /* disable PLLM, PLLP and PLLC */
        ldr     r0, [r5, #CLK_RESET_PLLM_BASE]
        bic     r0, r0, #(1 << 30)
        str     r0, [r5, #CLK_RESET_PLLM_BASE]
        ldr     r0, [r5, #CLK_RESET_PLLP_BASE]
        bic     r0, r0, #(1 << 30)
        str     r0, [r5, #CLK_RESET_PLLP_BASE]
        ldr     r0, [r5, #CLK_RESET_PLLC_BASE]
        bic     r0, r0, #(1 << 30)
        str     r0, [r5, #CLK_RESET_PLLC_BASE]

        /* switch to CLKS */
        mov     r0, #0  /* brust policy = 32KHz */
        str     r0, [r5, #CLK_RESET_SCLK_BURST]

        ret     lr

/*
 * tegra20_enter_sleep
 *
 * uses flow controller to enter sleep state
 * executes from IRAM with SDRAM in selfrefresh when target state is LP0 or LP1
 * executes from SDRAM with target state is LP2
 */
tegra20_enter_sleep:
        mov32   r6, TEGRA_FLOW_CTRL_BASE

        mov     r0, #FLOW_CTRL_WAIT_FOR_INTERRUPT
        orr     r0, r0, #FLOW_CTRL_HALT_CPU_IRQ | FLOW_CTRL_HALT_CPU_FIQ
        cpu_id  r1
        cpu_to_halt_reg r1, r1
        str     r0, [r6, r1]
        dsb
        ldr     r0, [r6, r1] /* memory barrier */

halted:
        dsb
        wfe     /* CPU should be power gated here */
        isb
        b       halted

/*
 * tegra20_sdram_self_refresh
 *
 * called with MMU off and caches disabled
 * puts sdram in self refresh
 * must be executed from IRAM
 */
tegra20_sdram_self_refresh:
        mov32   r1, TEGRA_EMC_BASE      @ r1 reserved for emc base addr

        mov     r2, #3
        str     r2, [r1, #EMC_REQ_CTRL] @ stall incoming DRAM requests

emcidle:
        ldr     r2, [r1, #EMC_EMC_STATUS]
        tst     r2, #4
        beq     emcidle

        mov     r2, #1
        str     r2, [r1, #EMC_SELF_REF]

        emc_device_mask r2, r1

emcself:
        ldr     r3, [r1, #EMC_EMC_STATUS]
        and     r3, r3, r2
        cmp     r3, r2
        bne     emcself                 @ loop until DDR in self-refresh

        adr     r2, tegra20_sdram_pad_address
        adr     r3, tegra20_sdram_pad_safe
        adr     r4, tegra20_sdram_pad_save
        mov     r5, #0

        ldr     r6, tegra20_sdram_pad_size
padsave:
        ldr     r0, [r2, r5]            @ r0 is the addr in the pad_address

        ldr     r1, [r0]
        str     r1, [r4, r5]            @ save the content of the addr

        ldr     r1, [r3, r5]
        str     r1, [r0]                @ set the save val to the addr

        add     r5, r5, #4
        cmp     r6, r5
        bne     padsave
padsave_done:

        mov32   r5, TEGRA_CLK_RESET_BASE
        ldr     r0, [r5, #CLK_RESET_SCLK_BURST]
        adr     r2, tegra20_sclk_save
        str     r0, [r2]
        dsb
        ret     lr

tegra20_sdram_pad_address:
        .word   TEGRA_APB_MISC_BASE + APB_MISC_XM2CFGCPADCTRL
        .word   TEGRA_APB_MISC_BASE + APB_MISC_XM2CFGDPADCTRL
        .word   TEGRA_APB_MISC_BASE + APB_MISC_XM2CLKCFGPADCTRL
        .word   TEGRA_APB_MISC_BASE + APB_MISC_XM2COMPPADCTRL
        .word   TEGRA_APB_MISC_BASE + APB_MISC_XM2VTTGENPADCTRL
        .word   TEGRA_APB_MISC_BASE + APB_MISC_XM2CFGCPADCTRL2
        .word   TEGRA_APB_MISC_BASE + APB_MISC_XM2CFGDPADCTRL2

tegra20_sdram_pad_size:
        .word   tegra20_sdram_pad_size - tegra20_sdram_pad_address

tegra20_sdram_pad_safe:
        .word   0x8
        .word   0x8
        .word   0x0
        .word   0x8
        .word   0x5500
        .word   0x08080040
        .word   0x0

tegra20_sclk_save:
        .word   0x0

tegra20_sdram_pad_save:
        .rept (tegra20_sdram_pad_size - tegra20_sdram_pad_address) / 4
        .long   0
        .endr

        .ltorg
/* dummy symbol for end of IRAM */
        .align L1_CACHE_SHIFT
        .globl tegra20_iram_end
tegra20_iram_end:
        b       .
#endif