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kernel boot 过程，设备树初始化 reserved-memory 节点： early_init_fdt_scan_reserved_mem() fdt_scan_reserved_mem(); fdt_init_reserved_mem(); static int __init fdt_scan_reserved_mem(void) { int node, child; const void *fdt = initial_boot_params; node = fdt_path_offset(fdt, "/reserved-memory"); fdt_for_each_subnode(child, fdt, node) { const char *uname; int err; if (!of_fdt_device_is_available(fdt, child)) continue; uname = fdt_get_name(fdt, child, NULL); /// 存在 reg 属性的情况 err = __reserved_mem_reserve_reg(child, uname); /// 不存在 reg 属性的情况，存在 size 属性 if (err == -ENOENT && of_get_flat_dt_prop(child, "size", NULL)) fdt_reserved_mem_save_node(child, uname, 0, 0); } return 0; } /// 先预留 rmem 的 base 和 size 都为 0 void __init fdt_reserved_mem_save_node(unsigned long node, const char *uname, phys_addr_t base, phys_addr_t size) { struct reserved_mem *rmem = &reserved_mem[reserved_mem_count]; rmem->fdt_node = node; rmem->name = uname; rmem->base = base; rmem->size = size; reserved_mem_count++; return; } void __init fdt_init_reserved_mem(void) { int i; for (i = 0; i < reserved_mem_count; i++) { struct reserved_mem *rmem = &reserved_mem[i]; unsigned long node = rmem->fdt_node; int len; const __be32 *prop; int err = 0; bool nomap; nomap = of_get_flat_dt_prop(node, "no-map", NULL) !...

3 min

Data Structure struct software_node { const char *name; const struct software_node *parent; const struct property_entry *properties; }; struct swnode { struct kobject kobj; struct fwnode_handle fwnode; const struct software_node *node; int id; /* hierarchy */ struct ida child_ids; struct list_head entry; struct list_head children; struct swnode *parent; unsigned int allocated:1; unsigned int managed:1; }; Provider software_node_register()注册单个 software node, software_node_register_node_group()注册一组 software nodes. 都是将 software nodes 挂入一个全局链表. // 定义属性 static const struct property_entry my_device_properties[] = { PROPERTY_ENTRY_U32("reg", 0), PROPERTY_ENTRY_U32("my_property", 1234), { } }; // 定义 software node static const struct software_node my_device_node = { ....

2 min

IPCam 3917 isp 模块图: 信号处理路径模块： Crop：裁剪模块，用于裁剪图像的特定区域 BLC：黑电平补偿(Black level Correction) DPC: 坏点校正(Defect Pixel Correction) 2DNR: 2D降噪(2D Noise Reduction) GE: 边缘增强(Gain Enhancement) 3DNR & GE：3D降噪和增益增强 AE Short/Long Gain：自动曝光短/长时间增益控制 HDR Fusion：高动态范围图像融合，合并不同曝光的图像 镜头校正模块： Circle Lens Shading：圆形镜头阴影校正 Grid Lens Shading：网格镜头阴影校正 色彩处理模块： YUV to RGB：YUV色彩空间转换为RGB INTP：demosaic颜色插值, 从raw格式转换到rgb格式 CCM：色彩校正矩阵(Color Correction Matrix) RGB Gamma：RGB伽马校正 WDR：宽动态范围(Wide Dynamic Range)处理 YUV处理模块： YUV420 To YUV422：YUV色彩格式转换 YUV422 To YUV444：YUV色彩格式转换 RGB2YUV444：RGB转YUV444格式 Global Curve：全局曲线调整 UV Tune & UVS：UV通道调整和UV抑制 统计和分析模块： AF Statistics：自动对焦统计数据 AE Short/Long Statistics：自动曝光短/长时间统计数据 Raw Statistics：原始图像统计数据...

1 min

libisp api: global api: rts_av_isp_init/cleanup rts_av_isp_start/stop rts_av_isp_get_status rts_av_isp_register/unregister/get_algo rts_av_isp_bind/unbind_algo rts_av_isp_register/unregister/get/check_sensor rts_av_isp_bind/unbind_sensor rts_av_isp_register_iq mipi out api: rts_av_isp_set_mipiout rts_av_isp_get_mipiout v4l2 control: rts_isp_v4l2_query_ctrl rts_isp_v4l2_query_menu rts_isp_v4l2_g_ctrl rts_isp_v4l2_s_ctrl rts_isp_v4l2_query_ext_ctrl rts_isp_v4l2_g_ext_ctrls rts_isp_v4l2_s_ext_ctrls rts_isp_v4l2_try_ext_ctrls sensor: private mask: 3A Setting: 3A Statis: IQ tuning: other: struct isp_core { struct isp_mod_hash_table hash; struct isp_notify notify; struct v4l2_ctrl_handler ctrl_handler; struct isp_statis statis; struct isp_iq iq; int initialized:1; int running:1; }; hash: hash table, 用来保存 modules. notify: ctrl_hander: statis: iq: initialized: isp_core_init() 之后置 1....

2 min

Chapter 2 Terminology Lane: 单向物理传输 lane, 2(D-PHY) or 3(C-PHY) wire interface for clock or data transmission. Virtual channel: 逻辑层面的概念，每个虚拟通道的数据彼此独立，在 lane 上交错发送，包含标识信息，指明属于哪个外设/通道。 Chapter 7 Physical Layer 有两种 physical layer，D-PHY 和 C-PHY, transmitter 和 receiver 需要一致。 7.1 D-PHY Physical Layer option D-PHY 由多条单向的 data lanes 和一条 clk lane。 对于 clk lane, transmitter 和 receiver 必须实现 continuous clock，non-continuous clock 是可选的。 continuous clk: 保持在 high-speed mode. non-continuous clk: 在两笔数据包之间进入 LP-11 state. 7.2 C-PHY Physical Layer option Chapter 9 Low Level Protocol Features:...

2 min

struct rtscam_soc_dev { struct device *dev; void __iomem *base; unsigned long iostart; unsigned int iosize; int initialized; atomic_t init_count; const struct vb2_mem_ops *mem_ops; struct rtscam_sensor_fps sensor_fps; struct rtscam_video_device rvdev; struct rtscam_soc_slot_info slot_info[RTSCAM_MAX_STM_COUNT]; struct rtscam_ge_device *mem_dev; struct rtscam_ge_device *cam_dev; struct rtscam_ge_device *ctrl_dev; struct rtscam_region td_config; struct rtscam_soc_icfg icfgs[RTSCAM_YUV_MAX_STRM_NUM]; unsigned int icfg_count; struct rtscam_soc_rgbcfg rgbcfg; char name[PLATFORM_NAME_SIZE]; kernel_ulong_t devtype; struct rtscam_mem_info *rtsmem; int pause_flag; unsigned long drop_frames; unsigned long drops[RTSCAM_MAX_STM_COUNT]; int keep_user_setting; struct rtscam_subdev_t *subdev; struct rtscam_soc_video_in *video_in; }; initialized: 是否初始化....

2 min

v4l-ctl media-ctl media-ctl.c -p: 打印 device topology $ media-ctl -p --print-dot: 输出 graphviz DOT 格式图形描述。 # 将输出保存到文件并转换为图像 $ media-ctl --print-dot > topology.dot $ dot -Tpng topology.dot -o topology.png -e: 指定某个 entity name, 打印属于哪个 device $ media-ctl -e rtsisp_video0 /dev/video0 --get-v4l2 or --get-format: 查看某个 pad 的格式 # 使用entity ID $ media-ctl --get-v4l2 0:1 # entity 0的pad 1 $ media-ctl --get-v4l2 5:0 # entity 5的pad 0 # 使用entity 名称 $ media-ctl --get-v4l2 '"sensor":1' # 名为"sensor"的entity的pad 1 $ media-ctl --get-v4l2 '"isp":0' # 名为"isp"的entity的pad 0 -r: reset all links to inactive...

2 min

Syntax --- title: Bank example --- classDiagram class BankAccount BankAccount : +String owner BankAccount : +Bigdecimal balance BankAccount : +deposit(amount) BankAccount : +withdrawal(amount) classDiagram class BankAccount BankAccount : +String owner BankAccount : +Bigdecimal balance BankAccount : +deposit(amount) BankAccount : +withdrawal(amount) Define a class class label classDiagram class Animal["Animal with a label"] class Car["Car with *! symbols"] Animal --> Car classDiagram class Animal["Animal with a label"] class Car["Car with *! symbols"] Animal --> Car Define members of a class classDiagram class BankAccount{ +String owner +BigDecimal balance +deposit(amount) +withdrawal(amount) } classDiagram class BankAccount{ +String owner +BigDecimal balance +deposit(amount) bool +withdrawal(amount) int } 区别 attributes 和 methods 的方法是，带()的是 methods。...

2 min

Syntax ->> 同步消息，-)异步消息。 sequenceDiagram Alice->>John: Hello John, how are you? John-->>Alice: Great! Alice-)John: See you later! sequenceDiagram Alice->>John: Hello John, how are you? John-->>Alice: Great! Alice-)John: See you later! Participants sequenceDiagram participant Alice participant Bob Bob->>Alice: Hi Alice Alice->>Bob: Hi Bob sequenceDiagram participant Alice participant Bob Bob->>Alice: Hi Alice Alice->>Bob: Hi Bob Actors actor 会有一个人物的标志。 sequenceDiagram actor Alice actor Bob Alice->>Bob: Hi Bob Bob->>Alice: Hi Alice sequenceDiagram actor Alice actor Bob Alice->>Bob: Hi Bob Bob->>Alice: Hi Alice Aliases sequenceDiagram participant A as Alice participant J as John A->>J: Hello John, how are you?...

2 min

Lab >>> print('Go') Go HW Q1 A Plus Abs B python3 ok -q a_plus_abs_b --local def a_plus_abs_b(a, b): if b < 0: f = sub else: f = add return f(a, b) Q2 Two of Three python3 ok -q two_of_three --local 返回三个数中最小的两个数。先取 min(i, j)得到较小的一个数，在从 min(max(i, j), k)中得到第二小的数。 def two_of_three(i, j, k): return min(i, j)**2 + min(max(i, j), k)**2 Q3 Largest Factor python3 ok -q largest_factor --local 返回能被整除的最大数。从 1 到 n 遍历，如果 n%i==0 即能够整除，返回最大值。...

1 min