// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
 * Copyright (C) 2019-2024 Linaro Ltd.
 */

#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/iommu.h>
#include <linux/platform_device.h>
#include <linux/types.h>

#include <linux/soc/qcom/smem.h>

#include "gsi_trans.h"
#include "ipa.h"
#include "ipa_cmd.h"
#include "ipa_data.h"
#include "ipa_mem.h"
#include "ipa_reg.h"
#include "ipa_table.h"

/* "Canary" value placed between memory regions to detect overflow */
#define IPA_MEM_CANARY_VAL              cpu_to_le32(0xdeadbeef)

/* SMEM host id representing the modem. */
#define QCOM_SMEM_HOST_MODEM    1

#define SMEM_IPA_FILTER_TABLE   497

const struct ipa_mem *ipa_mem_find(struct ipa *ipa, enum ipa_mem_id mem_id)
{
        u32 i;

        for (i = 0; i < ipa->mem_count; i++) {
                const struct ipa_mem *mem = &ipa->mem[i];

                if (mem->id == mem_id)
                        return mem;
        }

        return NULL;
}

/* Add an immediate command to a transaction that zeroes a memory region */
static void
ipa_mem_zero_region_add(struct gsi_trans *trans, enum ipa_mem_id mem_id)
{
        struct ipa *ipa = container_of(trans->gsi, struct ipa, gsi);
        const struct ipa_mem *mem = ipa_mem_find(ipa, mem_id);
        dma_addr_t addr = ipa->zero_addr;

        if (!mem->size)
                return;

        ipa_cmd_dma_shared_mem_add(trans, mem->offset, mem->size, addr, true);
}

/**
 * ipa_mem_setup() - Set up IPA AP and modem shared memory areas
 * @ipa:        IPA pointer
 *
 * Set up the shared memory regions in IPA local memory.  This involves
 * zero-filling memory regions, and in the case of header memory, telling
 * the IPA where it's located.
 *
 * This function performs the initial setup of this memory.  If the modem
 * crashes, its regions are re-zeroed in ipa_mem_zero_modem().
 *
 * The AP informs the modem where its portions of memory are located
 * in a QMI exchange that occurs at modem startup.
 *
 * There is no need for a matching ipa_mem_teardown() function.
 *
 * Return:      0 if successful, or a negative error code
 */
int ipa_mem_setup(struct ipa *ipa)
{
        dma_addr_t addr = ipa->zero_addr;
        const struct ipa_mem *mem;
        struct gsi_trans *trans;
        const struct reg *reg;
        u32 offset;
        u16 size;
        u32 val;

        /* Get a transaction to define the header memory region and to zero
         * the processing context and modem memory regions.
         */
        trans = ipa_cmd_trans_alloc(ipa, 4);
        if (!trans) {
                dev_err(ipa->dev, "no transaction for memory setup\n");
                return -EBUSY;
        }

        /* Initialize IPA-local header memory.  The AP header region, if
         * present, is contiguous with and follows the modem header region,
         * and they are initialized together.
         */
        mem = ipa_mem_find(ipa, IPA_MEM_MODEM_HEADER);
        offset = mem->offset;
        size = mem->size;
        mem = ipa_mem_find(ipa, IPA_MEM_AP_HEADER);
        if (mem)
                size += mem->size;

        ipa_cmd_hdr_init_local_add(trans, offset, size, addr);

        ipa_mem_zero_region_add(trans, IPA_MEM_MODEM_PROC_CTX);
        ipa_mem_zero_region_add(trans, IPA_MEM_AP_PROC_CTX);
        ipa_mem_zero_region_add(trans, IPA_MEM_MODEM);

        gsi_trans_commit_wait(trans);

        /* Tell the hardware where the processing context area is located */
        mem = ipa_mem_find(ipa, IPA_MEM_MODEM_PROC_CTX);
        offset = ipa->mem_offset + mem->offset;

        reg = ipa_reg(ipa, LOCAL_PKT_PROC_CNTXT);
        val = reg_encode(reg, IPA_BASE_ADDR, offset);
        iowrite32(val, ipa->reg_virt + reg_offset(reg));

        return 0;
}

/* Is the given memory region ID is valid for the current IPA version? */
static bool ipa_mem_id_valid(struct ipa *ipa, enum ipa_mem_id mem_id)
{
        enum ipa_version version = ipa->version;

        switch (mem_id) {
        case IPA_MEM_UC_SHARED:
        case IPA_MEM_UC_INFO:
        case IPA_MEM_V4_FILTER_HASHED:
        case IPA_MEM_V4_FILTER:
        case IPA_MEM_V6_FILTER_HASHED:
        case IPA_MEM_V6_FILTER:
        case IPA_MEM_V4_ROUTE_HASHED:
        case IPA_MEM_V4_ROUTE:
        case IPA_MEM_V6_ROUTE_HASHED:
        case IPA_MEM_V6_ROUTE:
        case IPA_MEM_MODEM_HEADER:
        case IPA_MEM_AP_HEADER:
        case IPA_MEM_MODEM_PROC_CTX:
        case IPA_MEM_AP_PROC_CTX:
        case IPA_MEM_MODEM:
        case IPA_MEM_UC_EVENT_RING:
        case IPA_MEM_PDN_CONFIG:
        case IPA_MEM_STATS_QUOTA_MODEM:
        case IPA_MEM_STATS_QUOTA_AP:
        case IPA_MEM_END_MARKER:        /* pseudo region */
                break;

        case IPA_MEM_STATS_TETHERING:
        case IPA_MEM_STATS_DROP:
                if (version < IPA_VERSION_4_0)
                        return false;
                break;

        case IPA_MEM_STATS_V4_FILTER:
        case IPA_MEM_STATS_V6_FILTER:
        case IPA_MEM_STATS_V4_ROUTE:
        case IPA_MEM_STATS_V6_ROUTE:
                if (version < IPA_VERSION_4_0 || version > IPA_VERSION_4_2)
                        return false;
                break;

        case IPA_MEM_AP_V4_FILTER:
        case IPA_MEM_AP_V6_FILTER:
                if (version < IPA_VERSION_5_0)
                        return false;
                break;

        case IPA_MEM_NAT_TABLE:
        case IPA_MEM_STATS_FILTER_ROUTE:
                if (version < IPA_VERSION_4_5)
                        return false;
                break;

        default:
                return false;
        }

        return true;
}

/* Must the given memory region be present in the configuration? */
static bool ipa_mem_id_required(struct ipa *ipa, enum ipa_mem_id mem_id)
{
        switch (mem_id) {
        case IPA_MEM_UC_SHARED:
        case IPA_MEM_UC_INFO:
        case IPA_MEM_V4_FILTER_HASHED:
        case IPA_MEM_V4_FILTER:
        case IPA_MEM_V6_FILTER_HASHED:
        case IPA_MEM_V6_FILTER:
        case IPA_MEM_V4_ROUTE_HASHED:
        case IPA_MEM_V4_ROUTE:
        case IPA_MEM_V6_ROUTE_HASHED:
        case IPA_MEM_V6_ROUTE:
        case IPA_MEM_MODEM_HEADER:
        case IPA_MEM_MODEM_PROC_CTX:
        case IPA_MEM_AP_PROC_CTX:
        case IPA_MEM_MODEM:
                return true;

        case IPA_MEM_PDN_CONFIG:
        case IPA_MEM_STATS_QUOTA_MODEM:
                return ipa->version >= IPA_VERSION_4_0;

        case IPA_MEM_STATS_TETHERING:
                return ipa->version >= IPA_VERSION_4_0 &&
                        ipa->version != IPA_VERSION_5_0;

        default:
                return false;           /* Anything else is optional */
        }
}

static bool ipa_mem_valid_one(struct ipa *ipa, const struct ipa_mem *mem)
{
        enum ipa_mem_id mem_id = mem->id;
        struct device *dev = ipa->dev;
        u16 size_multiple;

        /* Make sure the memory region is valid for this version of IPA */
        if (!ipa_mem_id_valid(ipa, mem_id)) {
                dev_err(dev, "region id %u not valid\n", mem_id);
                return false;
        }

        if (!mem->size && !mem->canary_count) {
                dev_err(dev, "empty memory region %u\n", mem_id);
                return false;
        }

        /* Other than modem memory, sizes must be a multiple of 8 */
        size_multiple = mem_id == IPA_MEM_MODEM ? 4 : 8;
        if (mem->size % size_multiple)
                dev_err(dev, "region %u size not a multiple of %u bytes\n",
                        mem_id, size_multiple);
        else if (mem->offset % 8)
                dev_err(dev, "region %u offset not 8-byte aligned\n", mem_id);
        else if (mem->offset < mem->canary_count * sizeof(__le32))
                dev_err(dev, "region %u offset too small for %hu canaries\n",
                        mem_id, mem->canary_count);
        else if (mem_id == IPA_MEM_END_MARKER && mem->size)
                dev_err(dev, "non-zero end marker region size\n");
        else
                return true;

        return false;
}

/* Verify each defined memory region is valid. */
static bool ipa_mem_valid(struct ipa *ipa, const struct ipa_mem_data *mem_data)
{
        DECLARE_BITMAP(regions, IPA_MEM_COUNT) = { };
        struct device *dev = ipa->dev;
        enum ipa_mem_id mem_id;
        u32 i;

        if (mem_data->local_count > IPA_MEM_COUNT) {
                dev_err(dev, "too many memory regions (%u > %u)\n",
                        mem_data->local_count, IPA_MEM_COUNT);
                return false;
        }

        for (i = 0; i < mem_data->local_count; i++) {
                const struct ipa_mem *mem = &mem_data->local[i];

                if (__test_and_set_bit(mem->id, regions)) {
                        dev_err(dev, "duplicate memory region %u\n", mem->id);
                        return false;
                }

                /* Defined regions have non-zero size and/or canary count */
                if (!ipa_mem_valid_one(ipa, mem))
                        return false;
        }

        /* Now see if any required regions are not defined */
        for_each_clear_bit(mem_id, regions, IPA_MEM_COUNT) {
                if (ipa_mem_id_required(ipa, mem_id))
                        dev_err(dev, "required memory region %u missing\n",
                                mem_id);
        }

        return true;
}

/* Do all memory regions fit within the IPA local memory? */
static bool ipa_mem_size_valid(struct ipa *ipa)
{
        struct device *dev = ipa->dev;
        u32 limit = ipa->mem_size;
        u32 i;

        for (i = 0; i < ipa->mem_count; i++) {
                const struct ipa_mem *mem = &ipa->mem[i];

                if (mem->offset + mem->size <= limit)
                        continue;

                dev_err(dev, "region %u ends beyond memory limit (0x%08x)\n",
                        mem->id, limit);

                return false;
        }

        return true;
}

/**
 * ipa_mem_config() - Configure IPA shared memory
 * @ipa:        IPA pointer
 *
 * Return:      0 if successful, or a negative error code
 */
int ipa_mem_config(struct ipa *ipa)
{
        struct device *dev = ipa->dev;
        const struct ipa_mem *mem;
        const struct reg *reg;
        dma_addr_t addr;
        u32 mem_size;
        void *virt;
        u32 val;
        u32 i;

        /* Check the advertised location and size of the shared memory area */
        reg = ipa_reg(ipa, SHARED_MEM_SIZE);
        val = ioread32(ipa->reg_virt + reg_offset(reg));

        /* The fields in the register are in 8 byte units */
        ipa->mem_offset = 8 * reg_decode(reg, MEM_BADDR, val);

        /* Make sure the end is within the region's mapped space */
        mem_size = 8 * reg_decode(reg, MEM_SIZE, val);

        /* If the sizes don't match, issue a warning */
        if (ipa->mem_offset + mem_size < ipa->mem_size) {
                dev_warn(dev, "limiting IPA memory size to 0x%08x\n",
                         mem_size);
                ipa->mem_size = mem_size;
        } else if (ipa->mem_offset + mem_size > ipa->mem_size) {
                dev_dbg(dev, "ignoring larger reported memory size: 0x%08x\n",
                        mem_size);
        }

        /* We know our memory size; make sure regions are all in range */
        if (!ipa_mem_size_valid(ipa))
                return -EINVAL;

        /* Prealloc DMA memory for zeroing regions */
        virt = dma_alloc_coherent(dev, IPA_MEM_MAX, &addr, GFP_KERNEL);
        if (!virt)
                return -ENOMEM;
        ipa->zero_addr = addr;
        ipa->zero_virt = virt;
        ipa->zero_size = IPA_MEM_MAX;

        /* For each defined region, write "canary" values in the
         * space prior to the region's base address if indicated.
         */
        for (i = 0; i < ipa->mem_count; i++) {
                u16 canary_count = ipa->mem[i].canary_count;
                __le32 *canary;

                if (!canary_count)
                        continue;

                /* Write canary values in the space before the region */
                canary = ipa->mem_virt + ipa->mem_offset + ipa->mem[i].offset;
                do
                        *--canary = IPA_MEM_CANARY_VAL;
                while (--canary_count);
        }

        /* Verify the microcontroller ring alignment (if defined) */
        mem = ipa_mem_find(ipa, IPA_MEM_UC_EVENT_RING);
        if (mem && mem->offset % 1024) {
                dev_err(dev, "microcontroller ring not 1024-byte aligned\n");
                goto err_dma_free;
        }

        return 0;

err_dma_free:
        dma_free_coherent(dev, IPA_MEM_MAX, ipa->zero_virt, ipa->zero_addr);

        return -EINVAL;
}

/* Inverse of ipa_mem_config() */
void ipa_mem_deconfig(struct ipa *ipa)
{
        struct device *dev = ipa->dev;

        dma_free_coherent(dev, ipa->zero_size, ipa->zero_virt, ipa->zero_addr);
        ipa->zero_size = 0;
        ipa->zero_virt = NULL;
        ipa->zero_addr = 0;
}

/**
 * ipa_mem_zero_modem() - Zero IPA-local memory regions owned by the modem
 * @ipa:        IPA pointer
 *
 * Zero regions of IPA-local memory used by the modem.  These are configured
 * (and initially zeroed) by ipa_mem_setup(), but if the modem crashes and
 * restarts via SSR we need to re-initialize them.  A QMI message tells the
 * modem where to find regions of IPA local memory it needs to know about
 * (these included).
 */
int ipa_mem_zero_modem(struct ipa *ipa)
{
        struct gsi_trans *trans;

        /* Get a transaction to zero the modem memory, modem header,
         * and modem processing context regions.
         */
        trans = ipa_cmd_trans_alloc(ipa, 3);
        if (!trans) {
                dev_err(ipa->dev, "no transaction to zero modem memory\n");
                return -EBUSY;
        }

        ipa_mem_zero_region_add(trans, IPA_MEM_MODEM_HEADER);
        ipa_mem_zero_region_add(trans, IPA_MEM_MODEM_PROC_CTX);
        ipa_mem_zero_region_add(trans, IPA_MEM_MODEM);

        gsi_trans_commit_wait(trans);

        return 0;
}

/**
 * ipa_imem_init() - Initialize IMEM memory used by the IPA
 * @ipa:        IPA pointer
 * @addr:       Physical address of the IPA region in IMEM
 * @size:       Size (bytes) of the IPA region in IMEM
 *
 * IMEM is a block of shared memory separate from system DRAM, and
 * a portion of this memory is available for the IPA to use.  The
 * modem accesses this memory directly, but the IPA accesses it
 * via the IOMMU, using the AP's credentials.
 *
 * If this region exists (size > 0) we map it for read/write access
 * through the IOMMU using the IPA device.
 *
 * Note: @addr and @size are not guaranteed to be page-aligned.
 */
static int ipa_imem_init(struct ipa *ipa, unsigned long addr, size_t size)
{
        struct device *dev = ipa->dev;
        struct iommu_domain *domain;
        unsigned long iova;
        phys_addr_t phys;
        int ret;

        if (!size)
                return 0;       /* IMEM memory not used */

        domain = iommu_get_domain_for_dev(dev);
        if (!domain) {
                dev_err(dev, "no IOMMU domain found for IMEM\n");
                return -EINVAL;
        }

        /* Align the address down and the size up to page boundaries */
        phys = addr & PAGE_MASK;
        size = PAGE_ALIGN(size + addr - phys);
        iova = phys;    /* We just want a direct mapping */

        ret = iommu_map(domain, iova, phys, size, IOMMU_READ | IOMMU_WRITE,
                        GFP_KERNEL);
        if (ret)
                return ret;

        ipa->imem_iova = iova;
        ipa->imem_size = size;

        return 0;
}

static void ipa_imem_exit(struct ipa *ipa)
{
        struct device *dev = ipa->dev;
        struct iommu_domain *domain;

        if (!ipa->imem_size)
                return;

        domain = iommu_get_domain_for_dev(dev);
        if (domain) {
                size_t size;

                size = iommu_unmap(domain, ipa->imem_iova, ipa->imem_size);
                if (size != ipa->imem_size)
                        dev_warn(dev, "unmapped %zu IMEM bytes, expected %zu\n",
                                 size, ipa->imem_size);
        } else {
                dev_err(dev, "couldn't get IPA IOMMU domain for IMEM\n");
        }

        ipa->imem_size = 0;
        ipa->imem_iova = 0;
}

/**
 * ipa_smem_init() - Initialize SMEM memory used by the IPA
 * @ipa:        IPA pointer
 * @size:       Size (bytes) of SMEM memory region
 *
 * SMEM is a managed block of shared DRAM, from which numbered "items"
 * can be allocated.  One item is designated for use by the IPA.
 *
 * The modem accesses SMEM memory directly, but the IPA accesses it
 * via the IOMMU, using the AP's credentials.
 *
 * If size provided is non-zero, we allocate it and map it for
 * access through the IOMMU.
 *
 * Note: @size and the item address are is not guaranteed to be page-aligned.
 */
static int ipa_smem_init(struct ipa *ipa, size_t size)
{
        struct device *dev = ipa->dev;
        struct iommu_domain *domain;
        unsigned long iova;
        phys_addr_t phys;
        phys_addr_t addr;
        size_t actual;
        void *virt;
        int ret;

        if (!size)
                return 0;       /* SMEM memory not used */

        /* SMEM is memory shared between the AP and another system entity
         * (in this case, the modem).  An allocation from SMEM is persistent
         * until the AP reboots; there is no way to free an allocated SMEM
         * region.  Allocation only reserves the space; to use it you need
         * to "get" a pointer it (this does not imply reference counting).
         * The item might have already been allocated, in which case we
         * use it unless the size isn't what we expect.
         */
        ret = qcom_smem_alloc(QCOM_SMEM_HOST_MODEM, SMEM_IPA_FILTER_TABLE, size);
        if (ret && ret != -EEXIST) {
                dev_err(dev, "error %d allocating size %zu SMEM item\n",
                        ret, size);
                return ret;
        }

        /* Now get the address of the SMEM memory region */
        virt = qcom_smem_get(QCOM_SMEM_HOST_MODEM, SMEM_IPA_FILTER_TABLE, &actual);
        if (IS_ERR(virt)) {
                ret = PTR_ERR(virt);
                dev_err(dev, "error %d getting SMEM item\n", ret);
                return ret;
        }

        /* In case the region was already allocated, verify the size */
        if (ret && actual != size) {
                dev_err(dev, "SMEM item has size %zu, expected %zu\n",
                        actual, size);
                return -EINVAL;
        }

        domain = iommu_get_domain_for_dev(dev);
        if (!domain) {
                dev_err(dev, "no IOMMU domain found for SMEM\n");
                return -EINVAL;
        }

        /* Align the address down and the size up to a page boundary */
        addr = qcom_smem_virt_to_phys(virt);
        phys = addr & PAGE_MASK;
        size = PAGE_ALIGN(size + addr - phys);
        iova = phys;    /* We just want a direct mapping */

        ret = iommu_map(domain, iova, phys, size, IOMMU_READ | IOMMU_WRITE,
                        GFP_KERNEL);
        if (ret)
                return ret;

        ipa->smem_iova = iova;
        ipa->smem_size = size;

        return 0;
}

static void ipa_smem_exit(struct ipa *ipa)
{
        struct device *dev = ipa->dev;
        struct iommu_domain *domain;

        domain = iommu_get_domain_for_dev(dev);
        if (domain) {
                size_t size;

                size = iommu_unmap(domain, ipa->smem_iova, ipa->smem_size);
                if (size != ipa->smem_size)
                        dev_warn(dev, "unmapped %zu SMEM bytes, expected %zu\n",
                                 size, ipa->smem_size);

        } else {
                dev_err(dev, "couldn't get IPA IOMMU domain for SMEM\n");
        }

        ipa->smem_size = 0;
        ipa->smem_iova = 0;
}

/* Perform memory region-related initialization */
int ipa_mem_init(struct ipa *ipa, struct platform_device *pdev,
                 const struct ipa_mem_data *mem_data)
{
        struct device *dev = &pdev->dev;
        struct resource *res;
        int ret;

        /* Make sure the set of defined memory regions is valid */
        if (!ipa_mem_valid(ipa, mem_data))
                return -EINVAL;

        ipa->mem_count = mem_data->local_count;
        ipa->mem = mem_data->local;

        /* Check the route and filter table memory regions */
        if (!ipa_table_mem_valid(ipa, false))
                return -EINVAL;
        if (!ipa_table_mem_valid(ipa, true))
                return -EINVAL;

        ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
        if (ret) {
                dev_err(dev, "error %d setting DMA mask\n", ret);
                return ret;
        }

        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ipa-shared");
        if (!res) {
                dev_err(dev,
                        "DT error getting \"ipa-shared\" memory property\n");
                return -ENODEV;
        }

        ipa->mem_virt = memremap(res->start, resource_size(res), MEMREMAP_WC);
        if (!ipa->mem_virt) {
                dev_err(dev, "unable to remap \"ipa-shared\" memory\n");
                return -ENOMEM;
        }

        ipa->mem_addr = res->start;
        ipa->mem_size = resource_size(res);

        ret = ipa_imem_init(ipa, mem_data->imem_addr, mem_data->imem_size);
        if (ret)
                goto err_unmap;

        ret = ipa_smem_init(ipa, mem_data->smem_size);
        if (ret)
                goto err_imem_exit;

        return 0;

err_imem_exit:
        ipa_imem_exit(ipa);
err_unmap:
        memunmap(ipa->mem_virt);

        return ret;
}

/* Inverse of ipa_mem_init() */
void ipa_mem_exit(struct ipa *ipa)
{
        ipa_smem_exit(ipa);
        ipa_imem_exit(ipa);
        memunmap(ipa->mem_virt);
}