// SPDX-License-Identifier: GPL-2.0
/*
 *    Copyright IBM Corp. 2015
 *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
 */

#include <linux/kernel.h>
#include <asm/processor.h>
#include <asm/lowcore.h>
#include <asm/ctlreg.h>
#include <asm/ebcdic.h>
#include <asm/irq.h>
#include <asm/sections.h>
#include <asm/physmem_info.h>
#include <asm/facility.h>
#include <asm/machine.h>
#include "sclp.h"
#include "sclp_rw.h"

static struct read_info_sccb __bootdata(sclp_info_sccb);
static int __bootdata(sclp_info_sccb_valid);
char *__bootdata_preserved(sclp_early_sccb);
int sclp_init_state = sclp_init_state_uninitialized;
/*
 * Used to keep track of the size of the event masks. Qemu until version 2.11
 * only supports 4 and needs a workaround.
 */
bool sclp_mask_compat_mode;

void sclp_early_wait_irq(void)
{
        unsigned long psw_mask, addr;
        psw_t psw_ext_save, psw_wait;
        union ctlreg0 cr0, cr0_new;

        local_ctl_store(0, &cr0.reg);
        cr0_new.val = cr0.val & ~CR0_IRQ_SUBCLASS_MASK;
        cr0_new.lap = 0;
        cr0_new.sssm = 1;
        local_ctl_load(0, &cr0_new.reg);

        psw_ext_save = get_lowcore()->external_new_psw;
        psw_mask = __extract_psw();
        get_lowcore()->external_new_psw.mask = psw_mask;
        psw_wait.mask = psw_mask | PSW_MASK_EXT | PSW_MASK_WAIT;
        get_lowcore()->ext_int_code = 0;

        do {
                asm volatile(
                        "       larl    %[addr],0f\n"
                        "       stg     %[addr],%[psw_wait_addr]\n"
                        "       stg     %[addr],%[psw_ext_addr]\n"
                        "       lpswe   %[psw_wait]\n"
                        "0:"
                        : [addr] "=&d" (addr),
                          [psw_wait_addr] "=Q" (psw_wait.addr),
                          [psw_ext_addr] "=Q" (get_lowcore()->external_new_psw.addr)
                        : [psw_wait] "Q" (psw_wait)
                        : "cc", "memory");
        } while (get_lowcore()->ext_int_code != EXT_IRQ_SERVICE_SIG);

        get_lowcore()->external_new_psw = psw_ext_save;
        local_ctl_load(0, &cr0.reg);
}

int sclp_early_cmd(sclp_cmdw_t cmd, void *sccb)
{
        unsigned long flags;
        int rc;

        flags = arch_local_irq_save();
        rc = sclp_service_call(cmd, sccb);
        if (rc)
                goto out;
        sclp_early_wait_irq();
out:
        arch_local_irq_restore(flags);
        return rc;
}

struct write_sccb {
        struct sccb_header header;
        struct msg_buf msg;
} __packed;

/* Output multi-line text using SCLP Message interface. */
static void sclp_early_print_lm(const char *str, unsigned int len)
{
        unsigned char *ptr, *end, ch;
        unsigned int count, offset;
        struct write_sccb *sccb;
        struct msg_buf *msg;
        struct mdb *mdb;
        struct mto *mto;
        struct go *go;

        sccb = (struct write_sccb *) sclp_early_sccb;
        end = (unsigned char *) sccb + EARLY_SCCB_SIZE - 1;
        memset(sccb, 0, sizeof(*sccb));
        ptr = (unsigned char *) &sccb->msg.mdb.mto;
        offset = 0;
        do {
                for (count = sizeof(*mto); offset < len; count++) {
                        ch = str[offset++];
                        if ((ch == 0x0a) || (ptr + count > end))
                                break;
                        ptr[count] = _ascebc[ch];
                }
                mto = (struct mto *) ptr;
                memset(mto, 0, sizeof(*mto));
                mto->length = count;
                mto->type = 4;
                mto->line_type_flags = LNTPFLGS_ENDTEXT;
                ptr += count;
        } while ((offset < len) && (ptr + sizeof(*mto) <= end));
        len = ptr - (unsigned char *) sccb;
        sccb->header.length = len - offsetof(struct write_sccb, header);
        msg = &sccb->msg;
        msg->header.type = EVTYP_MSG;
        msg->header.length = len - offsetof(struct write_sccb, msg.header);
        mdb = &msg->mdb;
        mdb->header.type = 1;
        mdb->header.tag = 0xD4C4C240;
        mdb->header.revision_code = 1;
        mdb->header.length = len - offsetof(struct write_sccb, msg.mdb.header);
        go = &mdb->go;
        go->length = sizeof(*go);
        go->type = 1;
        sclp_early_cmd(SCLP_CMDW_WRITE_EVENT_DATA, sccb);
}

struct vt220_sccb {
        struct sccb_header header;
        struct {
                struct evbuf_header header;
                char data[];
        } msg;
} __packed;

/* Output multi-line text using SCLP VT220 interface. */
static void sclp_early_print_vt220(const char *str, unsigned int len)
{
        struct vt220_sccb *sccb;

        sccb = (struct vt220_sccb *) sclp_early_sccb;
        if (sizeof(*sccb) + len >= EARLY_SCCB_SIZE)
                len = EARLY_SCCB_SIZE - sizeof(*sccb);
        memset(sccb, 0, sizeof(*sccb));
        memcpy(&sccb->msg.data, str, len);
        sccb->header.length = sizeof(*sccb) + len;
        sccb->msg.header.length = sizeof(sccb->msg) + len;
        sccb->msg.header.type = EVTYP_VT220MSG;
        sclp_early_cmd(SCLP_CMDW_WRITE_EVENT_DATA, sccb);
}

int sclp_early_set_event_mask(struct init_sccb *sccb,
                              sccb_mask_t receive_mask,
                              sccb_mask_t send_mask)
{
retry:
        memset(sccb, 0, sizeof(*sccb));
        sccb->header.length = sizeof(*sccb);
        if (sclp_mask_compat_mode)
                sccb->mask_length = SCLP_MASK_SIZE_COMPAT;
        else
                sccb->mask_length = sizeof(sccb_mask_t);
        sccb_set_recv_mask(sccb, receive_mask);
        sccb_set_send_mask(sccb, send_mask);
        if (sclp_early_cmd(SCLP_CMDW_WRITE_EVENT_MASK, sccb))
                return -EIO;
        if ((sccb->header.response_code == 0x74f0) && !sclp_mask_compat_mode) {
                sclp_mask_compat_mode = true;
                goto retry;
        }
        if (sccb->header.response_code != 0x20)
                return -EIO;
        return 0;
}

unsigned int sclp_early_con_check_linemode(struct init_sccb *sccb)
{
        if (!(sccb_get_sclp_send_mask(sccb) & EVTYP_OPCMD_MASK))
                return 0;
        if (!(sccb_get_sclp_recv_mask(sccb) & (EVTYP_MSG_MASK | EVTYP_PMSGCMD_MASK)))
                return 0;
        return 1;
}

unsigned int sclp_early_con_check_vt220(struct init_sccb *sccb)
{
        if (sccb_get_sclp_send_mask(sccb) & EVTYP_VT220MSG_MASK)
                return 1;
        return 0;
}

static int sclp_early_setup(int disable, int *have_linemode, int *have_vt220)
{
        unsigned long receive_mask, send_mask;
        struct init_sccb *sccb;
        int rc;

        BUILD_BUG_ON(sizeof(struct init_sccb) > PAGE_SIZE);

        *have_linemode = *have_vt220 = 0;
        sccb = (struct init_sccb *) sclp_early_sccb;
        receive_mask = disable ? 0 : EVTYP_OPCMD_MASK;
        send_mask = disable ? 0 : EVTYP_VT220MSG_MASK | EVTYP_MSG_MASK;
        rc = sclp_early_set_event_mask(sccb, receive_mask, send_mask);
        if (rc)
                return rc;
        *have_linemode = sclp_early_con_check_linemode(sccb);
        *have_vt220 = !!(sccb_get_send_mask(sccb) & EVTYP_VT220MSG_MASK);
        return rc;
}

void sclp_early_set_buffer(void *sccb)
{
        sclp_early_sccb = sccb;
}

/*
 * Output one or more lines of text on the SCLP console (VT220 and /
 * or line-mode).
 */
void __sclp_early_printk(const char *str, unsigned int len)
{
        int have_linemode, have_vt220;

        if (sclp_init_state != sclp_init_state_uninitialized)
                return;
        if (sclp_early_setup(0, &have_linemode, &have_vt220) != 0)
                return;
        if (have_linemode)
                sclp_early_print_lm(str, len);
        if (have_vt220)
                sclp_early_print_vt220(str, len);
        sclp_early_setup(1, &have_linemode, &have_vt220);
}

void sclp_early_printk(const char *str)
{
        __sclp_early_printk(str, strlen(str));
}

/*
 * Use sclp_emergency_printk() to print a string when the system is in a
 * state where regular console drivers cannot be assumed to work anymore.
 *
 * Callers must make sure that no concurrent SCLP requests are outstanding
 * and all other CPUs are stopped, or at least disabled for external
 * interrupts.
 */
void sclp_emergency_printk(const char *str)
{
        int have_linemode, have_vt220;
        unsigned int len;

        len = strlen(str);
        /*
         * Don't care about return values; if requests fail, just ignore and
         * continue to have a rather high chance that anything is printed.
         */
        sclp_early_setup(0, &have_linemode, &have_vt220);
        sclp_early_print_lm(str, len);
        sclp_early_print_vt220(str, len);
        sclp_early_setup(1, &have_linemode, &have_vt220);
}

/*
 * We can't pass sclp_info_sccb to sclp_early_cmd() here directly,
 * because it might not fulfil the requiremets for a SCLP communication buffer:
 *   - lie below 2G in memory
 *   - be page-aligned
 * Therefore, we use the buffer sclp_early_sccb (which fulfils all those
 * requirements) temporarily for communication and copy a received response
 * back into the buffer sclp_info_sccb upon successful completion.
 */
int __init sclp_early_read_info(void)
{
        int i;
        int length = test_facility(140) ? EXT_SCCB_READ_SCP : PAGE_SIZE;
        struct read_info_sccb *sccb = (struct read_info_sccb *)sclp_early_sccb;
        sclp_cmdw_t commands[] = {SCLP_CMDW_READ_SCP_INFO_FORCED,
                                  SCLP_CMDW_READ_SCP_INFO};

        for (i = 0; i < ARRAY_SIZE(commands); i++) {
                memset(sccb, 0, length);
                sccb->header.length = length;
                sccb->header.function_code = 0x80;
                sccb->header.control_mask[2] = 0x80;
                if (sclp_early_cmd(commands[i], sccb))
                        break;
                if (sccb->header.response_code == 0x10) {
                        memcpy(&sclp_info_sccb, sccb, length);
                        sclp_info_sccb_valid = 1;
                        return 0;
                }
                if (sccb->header.response_code != 0x1f0)
                        break;
        }
        return -EIO;
}

struct read_info_sccb * __init sclp_early_get_info(void)
{
        if (!sclp_info_sccb_valid)
                return NULL;

        return &sclp_info_sccb;
}

int __init sclp_early_get_memsize(unsigned long *mem)
{
        unsigned long rnmax;
        unsigned long rnsize;
        struct read_info_sccb *sccb = &sclp_info_sccb;

        if (!sclp_info_sccb_valid)
                return -EIO;

        rnmax = sccb->rnmax ? sccb->rnmax : sccb->rnmax2;
        rnsize = sccb->rnsize ? sccb->rnsize : sccb->rnsize2;
        rnsize <<= 20;
        *mem = rnsize * rnmax;
        return 0;
}

int __init sclp_early_get_hsa_size(unsigned long *hsa_size)
{
        if (!sclp_info_sccb_valid)
                return -EIO;

        *hsa_size = 0;
        if (sclp_info_sccb.hsa_size)
                *hsa_size = (sclp_info_sccb.hsa_size - 1) * PAGE_SIZE;
        return 0;
}

void __init sclp_early_detect_machine_features(void)
{
        struct read_info_sccb *sccb = &sclp_info_sccb;

        if (!sclp_info_sccb_valid)
                return;
        if (sccb->fac85 & 0x02)
                set_machine_feature(MFEATURE_ESOP);
        if (sccb->fac91 & 0x40)
                set_machine_feature(MFEATURE_TLB_GUEST);
}

#define SCLP_STORAGE_INFO_FACILITY     0x0000400000000000UL

void __weak __init add_physmem_online_range(u64 start, u64 end) {}
int __init sclp_early_read_storage_info(void)
{
        struct read_storage_sccb *sccb = (struct read_storage_sccb *)sclp_early_sccb;
        int rc, id, max_id = 0;
        unsigned long rn, rzm;
        sclp_cmdw_t command;
        u16 sn;

        if (!sclp_info_sccb_valid)
                return -EIO;

        if (!(sclp_info_sccb.facilities & SCLP_STORAGE_INFO_FACILITY))
                return -EOPNOTSUPP;

        rzm = sclp_info_sccb.rnsize ?: sclp_info_sccb.rnsize2;
        rzm <<= 20;

        for (id = 0; id <= max_id; id++) {
                memset(sclp_early_sccb, 0, EARLY_SCCB_SIZE);
                sccb->header.length = EARLY_SCCB_SIZE;
                command = SCLP_CMDW_READ_STORAGE_INFO | (id << 8);
                rc = sclp_early_cmd(command, sccb);
                if (rc)
                        goto fail;

                max_id = sccb->max_id;
                switch (sccb->header.response_code) {
                case 0x0010:
                        for (sn = 0; sn < sccb->assigned; sn++) {
                                if (!sccb->entries[sn])
                                        continue;
                                rn = sccb->entries[sn] >> 16;
                                add_physmem_online_range((rn - 1) * rzm, rn * rzm);
                        }
                        break;
                case 0x0310:
                case 0x0410:
                        break;
                default:
                        goto fail;
                }
        }

        return 0;
fail:
        physmem_info.range_count = 0;
        return -EIO;
}