Linux驱动基础：msm平台，modem等framework加载

DSP

Linux驱动基础：msm平台，modem等framework加载

2019-07-13 18:56发布生成海报

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msm平台，AP和CP封装在一起，公用一块内存。所以AP需要负责把整个modem, TZ , rpm等binary拷贝到内存中以供modem等subsystem去运行。那AP这边是怎么分配这些内存，又是怎么读出来相关的binary，又如何把binary上传上去的呢？？相关的feature

CONFIG_FW_LOADER
CONFIG_FW_LOADER_USER_HELPER

modem使用的内存申请

要设置modem的内存大小，必须首先需要确认modem binary的大小，modem需要使用的内存大小等。这个在CMA相关的内容中说过。这里在说一下高通msm8916平台，modem大小检查以及修改方法。
1) modem binary的大小可以从以下编译的log里边看出来！！(modem_proc/build/ms目录下的pplk-XXX.log或者build_xxxx.log)。
根据大小对齐1MB大小，就是modem binary需要流出来的大小。看如下例子里边的log，总的大小是77.04，
所以需要在上面的dtsi文件中留出来78MB就可以。

  Image loaded at virtual address 0xc0000000 
  Image:                                   55.44 MiB 
  AMSS Heap:                                7.50 MiB (dynamic) 
  MPSS Heap:                                4.00 MiB (dynamic) 
  DSM Pools:                                5.06 MiB  
  Q6Zip RO, Swap Pool:                      2.00 MiB (dynamic) 
  Q6Zip RW, Swap Pool:                      1.00 MiB (dynamic) 
  Q6Zip RW, dlpager Heap:                   1.00 MiB 
  Extra:                                    0.54 MiB 
  Pad ding:                                  0.37 MiB 
  End Address Alignment:                    0.13 MiB 
  Total:                                   77.04 MiB 
  Available:                                7.96 MiB

2) 然后去修改modem_proc/config/xxx/ 目录下的cust_config.xml文件中修改modem大小

      
        <physical_pool name="DEFAULT_PHYSPOOL"> 
             <region base="0x88000000"  size="0x5500000" /> 
             <region base="0x88000000" size="0x4E00000" /> 
        physical_pool>

以下是modem相关的device tree的设置。这些内容也在CMA和ion内存相关的帖子里边都讲过。
但之前有一个疑问就是，在CMA预留了一段内存之后，会把这个赋值给modem的dev->cma_area，然后在分配需要使用的内存的时候从dev->cma_area中取出来，那这个过程好像跟ion内存没有什么关系。能不能去掉下面msmxxx-ion.dtsi中
modem_adsp_mem相关的设置呢？？
是可以的！！！其他几个DMA区域，如果直接从CMA分配的话，应该都可以从msmxxx-ion.dtsi文件中去掉！！
也就是说下面qcom,ion-heap-type = “DMA”的部分其实都可以从msm8916-ion.dtsi文件中去掉，不影响。

        //modem相关内存的device tree设置
        //pil设备相关的device tree定义
        qcom,mss@4080000 {
            compatible = "qcom,pil-q6v56-mss";
            ....
            linux,contiguous-region = <&modem_adsp_mem>;
        };

        //msmxxx-ion.dtsi定义了如下，上面说了这个部分其实是可以去掉的，不会影响相关内存的分配！！
        qcom,ion-heap@26 { /* MODEM HEAP */
            compatible = "qcom,msm-ion-reserve";
            reg = <26>;
            linux,contiguous-region = <&modem_adsp_mem>;
            qcom,ion-heap-type = "DMA";
        };

        //msmxxx-memory.dtsi定义了如下内容
        modem_adsp_mem: modem_adsp_region@0 {
            linux,reserve-contiguous-region;
            linux,reserve-region;
            linux,remove-completely;
            reg = <0x0 0x86800000 0x0 0x05800000>;
            label = "modem_adsp_mem";
        };

modem_adsp_mem指定的区域，需要分配出来，以供下载modem binary。

//pil_mss_driver_probe()->pil_subsys_init() 
static int pil_subsys_init(struct modem_data *drv,
                    struct platform_device *pdev)
{
    ...
    drv->subsys_desc.name = "modem";
    drv->subsys_desc.dev = &pdev->dev;
    drv->subsys_desc.owner = THIS_MODULE;
    drv->subsys_desc.shutdown = modem_shutdown;
    drv->subsys_desc.powerup = modem_powerup;
    drv->subsys_desc.ramdump = modem_ramdump;
    drv->subsys_desc.free_memory = modem_free_memory;
    drv->subsys_desc.crash_shutdown = modem_crash_shutdown;
    drv->subsys_desc.err_fatal_handler = modem_err_fatal_intr_handler;
    drv->subsys_desc.stop_ack_handler = modem_stop_ack_intr_handler;
    drv->subsys_desc.wdog_bite_handler = modem_wdog_bite_intr_handler;

    drv->subsys = subsys_register(&drv->subsys_desc);

    drv->ramdump_dev = create_ramdump_device("modem", &pdev->dev);
    ...
    return ret;
}

之后在modem_powerup()的时候,会先根据modem binary的elf结构独处modem的大小等，然后计算出align之后应该的大小。
pil_boot()-> request_firmware()读出elf头并计算大小等。
在pil_setup_region()->pil_alloc_region()的时候，传进去的大小就是从上面读出来的大小。 pil_alloc_region min_addr = 0xc0000000 , max_addr = 0xc2b00000 , aligned_size = 0x2b00000 这里看着和实际的内存大小一致！！可能是因为留出来的CMA区域的大小正好和这个大小一致才这样的。
在实际调试过程中，也可以打印这个大小之后，调整CMA大小。再看看实际的CMA大小是怎么申请的。

//调用顺序
pil_boot()->pil_init_mmap()->pil_setup_region()->pil_alloc_region()->
dma_alloc_attrs()->arm_dma_alloc()->__dma_alloc()->__alloc_from_contiguous()->

这个调用的顺序，一步一步往下看可以看到，实际上分配的区域是一块CMA区域，而且就是在CMA注册之后，在相应的platform设备注册的时候保存到dev->cma_area中的区域。
在相应的设备注册的时候，如果设备的device tree中有”linux,contiguous-region”的时候，就会寻找相应的CMA区域并进行保留。这都是因为注册了platform_bus_typ的notifier函数 bus_register_notifier(&platform_bus_type, &cma_dev_init_nb); 看下面的log。

<6>[0.487642]  [0:swapper/0:1] cma: Assigned CMA region at 0 to 1de0000.qcom,venus device
<6>[0.489469]  [0:swapper/0:1] cma: Assigned CMA region at 0 to 4080000.qcom,mss device
<6>[0.490756]  [0:swapper/0:1] cma: Assigned CMA region at 0 to a21b000.qcom,pronto device
<6>[1.125342]  [0:swapper/0:1] cma: Assigned CMA region at 0 to 8.qcom,ion-heap device
<6>[1.125793]  [0:swapper/0:1] cma: Assigned CMA region at 0 to 1b.qcom,ion-heap device
<6>[1.126233]  [0:swapper/0:1] cma: Assigned CMA region at 0 to 1c.qcom,ion-heap device
<6>[1.126671]  [0:swapper/0:1] cma: Assigned CMA region at 0 to 17.qcom,ion-heap device
<6>[1.127298]  [0:swapper/0:1] cma: Assigned CMA region at 0 to 1a.qcom,ion-heap device

这里看到4080000.qcom,mss这个device相应的区域已经保留了CMA区域。
然后在上面进行分配的时候，在
__alloc_from_contiguous()->dma_alloc_from_contiguous()->dev_get_cma_area()函数中取到
相应的dev->cma_area。

modem相关内存的使用和下载

pil_load_seg()->request_firmware_direct()->_request_firmware()函数身生成相应的device节点，并通知ueventd去读取相应的binary然后下载。以下是pil_load_seg里边打印的正在试图下载的binary。

<6>[29.129737]  [1:init:1] pil_load_seg fw_name = modem.b02
<6>[29.157808]  [1:init:1] pil_load_seg fw_name = modem.b07
<6>[29.191477]  [1:init:1] pil_load_seg fw_name = modem.b17
<6>[29.348480]  [1:init:1] pil_load_seg fw_name = modem.b19
<6>[29.409733]  [1:init:1] pil_load_seg fw_name = modem.b20
<6>[29.489639]  [1:init:1] pil_load_seg fw_name = modem.b23
<6>[29.519624]  [1:init:1] pil_load_seg fw_name = modem.b24
<6>[29.549829]  [1:init:1] pil_load_seg fw_name = modem.b25
<6>[29.591918]  [1:init:1] pil_load_seg fw_name = modem.b27
<6>[31.997036]  [0:wcnss_service:307] pil_load_seg fw_name = wcnss.b02
<6>[32.658390]  [0:wcnss_service:307] pil_load_seg fw_name = wcnss.b04
<6>[32.693754]  [0:wcnss_service:307] pil_load_seg fw_name = wcnss.b06
<6>[32.848104]  [3:wcnss_service:307] pil_load_seg fw_name = wcnss.b09
<6>[32.854061]  [3:wcnss_service:307] pil_load_seg fw_name = wcnss.b10
<6>[32.876115]  [3:wcnss_service:307] pil_load_seg fw_name = wcnss.b11
<6>[37.384287]  [1:TimedEventQueue:771] pil_load_seg fw_name = venus.b02
<6>[37.438222]  [1:TimedEventQueue:771] pil_load_seg fw_name = venus.b03
<6>[37.484909]  [2:TimedEventQueue:771] pil_load_seg fw_name = venus.b04

在 _request_firmware()->fw_load_from_user_helper()->_request_firmware_load()函数中就在生成相应的dev节点，并通知ueventd。

static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
                  long timeout)
{
    int retval = 0;
    struct device *f_dev = &fw_priv->dev;
    struct firmware_buf *buf = fw_priv->buf;
    struct bin_attribute *fw_attr_data = buf->dest_addr ?
            &firmware_direct_attr_data : &firmware_attr_data;

    /* fall back on userspace loading */
    buf->is_paged_buf = buf->dest_addr ? false : true;

    dev_set_uevent_suppress(f_dev, true);

    /* Need to pin this module until class device is destroyed */
    __module_get(THIS_MODULE);

    retval = device_add(f_dev);

    //以下生成的data和loading节点，用于ueventd读取相应的binary，然后通过节点加载到内存的。

    //用于下载的节点，
    retval = device_create_bin_file(f_dev, fw_attr_data);

    //生成一个loading的节点，loading节点用于控制的
    retval = device_create_file(f_dev, &dev_attr_loading);
    if (retval) {
        dev_err(f_dev, "%s: device_create_file failed
", __func__);
        goto err_del_bin_attr;
    }

    if (uevent) { //这里正在通知ueventd
        dev_set_uevent_suppress(f_dev, false);
        dev_dbg(f_dev, "firmware: requesting %s
", buf->fw_id);
        if (timeout != MAX_SCHEDULE_TIMEOUT)
            schedule_delayed_work(&fw_priv->timeout_work, timeout);
        kobject_uevent(&fw_priv->dev.kobj, KOBJ_ADD);
    }
    wait_for_completion(&buf->completion);
    cancel_delayed_work_sync(&fw_priv->timeout_work);
}

_request_firmware() -> assign_firmware_buf() 这是做什么的？？来看一下ueventd.c文件中是怎么检测这个然后读binary，通过loading节点加载binary的。

int ueventd_main(int argc, char **argv){

    ...
    while(1) {
        ufd.revents = 0;
        nr = poll(&ufd, 1, -1);
        if (nr <= 0)
            continue;
        if (ufd.revents & POLLIN)
               handle_device_fd();
    }
}

void handle_device_fd(){
    ...
    handle_firmware_event(&uevent);//process_firmware_event()
}

#define SYSFS_PREFIX    "/sys"
#define FIRMWARE_DIR1   "/etc/firmware"
#define FIRMWARE_DIR2   "/vendor/firmware"
#define FIRMWARE_DIR3   "/firmware/image"
#define FIRMWARE_DIR4   "/firmware-modem/image"
#define DEVICES_BASE    "/devices/soc.0"

static void process_firmware_event(struct uevent *uevent){
    ...
    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
    l = asprintf(&loading, "%sloading", root);
    l = asprintf(&file1, FIRMWARE_DIR1"/%s", uevent->firmware);
    l = asprintf(&file2, FIRMWARE_DIR2"/%s", uevent->firmware);
    l = asprintf(&file3, FIRMWARE_DIR3"/%s", uevent->firmware);
    l = asprintf(&file4, FIRMWARE_DIR4"/%s", uevent->firmware);

    loading_fd = open(loading, O_WRONLY);
    ...
    if(!load_firmware(fw_fd, loading_fd, data_fd)) //加载binary
        INFO("firmware: copy success { '%s', '%s' }
", root, uevent->firmware);
    else
        INFO("firmware: copy failure { '%s', '%s' }
", root, uevent->firmware);

}

以下看看ueventd中，真正把读到的binary，传给kernel的函数

static int load_firmware(int fw_fd, int loading_fd, int data_fd)
{
    struct stat st;
    long len_to_copy;
    int ret = 0;

    //fstat查看binary的信息，读出来size等
    if(fstat(fw_fd, &st) < 0)
        return -1;
    len_to_copy = st.st_size;

    write(loading_fd, "1", 1);  /* start transfer */

    while (len_to_copy > 0) {
        char buf[PAGE_SIZE];
        ssize_t nr;
        //读
        nr = read(fw_fd, buf, sizeof(buf));
        if(!nr)
            break;
        if(nr < 0) {
            ret = -1;
            break;
        }

        len_to_copy -= nr;
        while (nr > 0) {
            ssize_t nw = 0;
            //写到data节点
            nw = write(data_fd, buf + nw, nr);
            if(nw <= 0) {
                ret = -1;
                goto out;
            }
            nr -= nw;
        }
    }

out:
    if(!ret) //loading节点用于通知kernel加载情况！！
        write(loading_fd, "0", 1);  /* successful end of transfer */
    else
        write(loading_fd, "-1", 2); /* abort transfer */

    return ret;
}

内核中，data节点出来write的函数在_request_firmware_load()中根据buf->dest_addr的值有所不同

static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
                  long timeout)
{
    ...
    struct bin_attribute *fw_attr_data = buf->dest_addr ?
            &firmware_direct_attr_data : &firmware_attr_data;
    ...

}

在下载modem.bxx的时候应该都是有buf->dest_addr才对

<6>[29.355860]  [0:init:1] pil_load_seg fw_name = modem.b02
<6>[29.361829]  [0:init:1] fw_load_from_user_helper start 
<6>[29.368051]  [0:init:1] _request_firmware_load buf->dest_addr = 0x86800000
<6>[29.380308]  [0:ueventd:230] firmware_loading_store started
...
<6>[29.391942]  [0:init:1] pil_load_seg fw_name = modem.b07
<6>[29.398801]  [0:init:1] fw_load_from_user_helper start 
<6>[29.404996]  [0:init:    1] _request_firmware_load buf->dest_addr = 0x86840000
...

//write(data_fd, buf + nw, nr); buf对应buffer？ offset? count对应nr??
static ssize_t firmware_direct_write(struct file *filp, struct kobject *kobj,
                   struct bin_attribute *bin_attr,
                   char *buffer, loff_t offset, size_t count)
{
    struct device *dev = kobj_to_dev(kobj);
    struct firmware_priv *fw_priv = to_firmware_priv(dev);
    //获取uevent读取modem binary时候读到的内容，保存在firmware_priv中。firmware_priv中的firmware_buf保存了binary的物理地址，大小等等信息

    struct firmware *fw;
    ssize_t retval;

    if (!capable(CAP_SYS_RAWIO))
        return -EPERM;

    mutex_lock(&fw_lock);
    fw = fw_priv->fw;
    if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->buf->status)) {
        retval = -ENODEV;
        goto out;
    }

    retval = __firmware_data_rw(fw_priv, buffer, &offset, count, 0);
    if (retval < 0)
        goto out;

    fw_priv->buf->size = max_t(size_t, offset, fw_priv->buf->size);
out:
    mutex_unlock(&fw_lock);
    return retval;
}

static int __firmware_data_rw(struct firmware_priv *fw_priv, char *buffer,
                loff_t *offset, size_t count, int read)
{
    u8 __iomem *fw_buf; 

    struct firmware_buf *buf = fw_priv->buf;
    int retval = count;

    if ((*offset + count) > buf->dest_size) {
        pr_debug("%s: Failed size check.
", __func__);
        retval = -EINVAL;
        goto out;
    }

    //fw_buf 就是要拷贝到内存中的modem binary物理地址对应的虚拟地址。
    //map_fw_mem函数中，会根据虚拟地址以及需要拷贝的大小，map出一段虚拟地址。
    //map一段物理地址，然后返回内核可以访问的虚拟地址，，这个是通过ioremap相关的函数实现的

    fw_buf = buf->map_fw_mem(buf->dest_addr + *offset, count,
                    buf->map_data);
    if (!fw_buf) {
        pr_debug("%s: Failed ioremap.
", __func__);
        retval = -ENOMEM;
        goto out;
    }

    //读写，直接拷贝就可以
    if (read)
        memcpy(buffer, fw_buf, count);
    else
        memcpy(fw_buf, buffer, count);

    *offset += count;
    buf->unmap_fw_mem(fw_buf, count, buf->map_data);

out:
    return retval;
}

static void *map_fw_mem(phys_addr_t paddr, size_t size, void *data)
{
    struct pil_map_fw_info *info = data;

    return dma_remap(info->dev, info->region, paddr, size,
                    &info->attrs);
}

static inline void *dma_remap(struct device *dev, void *cpu_addr,
        dma_addr_t dma_handle, size_t size, struct dma_attrs *attrs)
{
    const struct dma_map_ops *ops = get_dma_ops(dev);
    BUG_ON(!ops);

    if (!ops->remap) {
        WARN_ONCE(1, "Remap function not implemented for %pS
",
                ops->remap);
        return NULL;
    }

    return ops->remap(dev, cpu_addr, dma_handle, size, attrs);
}

static void *arm_dma_remap(struct device *dev, void *cpu_addr,
            dma_addr_t handle, size_t size,
            struct dma_attrs *attrs)
{
    struct page *page = pfn_to_page(dma_to_pfn(dev, handle));
    pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL);
    unsigned long offset = handle & ~PAGE_MASK;

    size = PAGE_ALIGN(size + offset);
    return __dma_alloc_remap(page, size, GFP_KERNEL, prot,
                    __builtin_return_address(0)) + offset;

}

static void *
__dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot,
    const void *caller)
{
    struct vm_struct *area;
    unsigned long addr;

    /*
     * DMA allocation can be mapped to user space, so lets
     * set VM_USERMAP flags too.
     */
    //得到一段满足要求的vm_struct。这里
    area = get_vm_area_caller(size, VM_ARM_DMA_CONSISTENT | VM_USERMAP,
                  caller);
    if (!area)
        return NULL;    
    addr = (unsigned long)area->addr; 
    area->phys_addr = __pfn_to_phys(page_to_pfn(page));

    //addr是得到的vm_struct对应的虚拟地址，内核可以访问的
    //所以根据物理地址以及对应的虚拟地址以及大小等情况，ioremap_page_range会做一个page table
    //这样内核就可以直接访问这段内存
    if (ioremap_page_range(addr, addr + size, area->phys_addr, prot)) {
        vunmap((void *)addr);
        return NULL;
    }
    return (void *)addr;//返回虚拟内存，现在这个虚拟内存就可以直接访问了
}

和ioremap_page_range()比较像。