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QC MSM平台显示屏Framebuffer设备注册过程

发布时间:2013-05-29 | 佚名:www.07net01.com

本文是Android Display部分分析的一部分,描述屏Framebuffer设备注册过程。

QC MSM7xxx/MSM8xxx平台本身就提供了很多接口的屏的支持,每种屏对应一个驱动文件。由于QC MSM平台显示驱动架构做了绝大部分的工作,驱动一块新的屏仅需要做很少量的工作。下面的过程是屏Framebuffer注册过程的分析。

设备资源申请是在MACHINE_DESC中实现的。示例如下:

3463MACHINE_START(MSM8930_CDP, "QCT MSM8930 CDP")
3464	.map_io = msm8930_map_io,
3465	.reserve = msm8930_reserve,
3466	.init_irq = msm8930_init_irq,
3467	.handle_irq = gic_handle_irq,
3468	.timer = &msm_timer,
3469	.init_machine = msm8930_cdp_init,
3470	.init_early = msm8930_allocate_memory_regions,
3471	.init_very_early = msm8930_early_memory,
3472	.restart = msm_restart,
3473MACHINE_END

machine_desc{.init_very_early, .init_early, .init_machine, .restart}, module_init driver的初始化顺序参考Machine_desc & boot & Kernel_init & initcall & module_init
在machine_desc.init中做了许多machine级别设备的注册工作,主要意图是做设备资源分配。该.init函数部分示例代码如下:

static void __init msm8930_cdp_init(void) @ kernel/arch/arm/mach-msm/board-8930.c
{
    …
platform_add_devices(common_devices, ARRAY_SIZE(common_devices));
	msm8930_init_gpu();    
	msm8930_init_mmc();
	msm8930_init_cam();
	msm8930_init_fb();
}

其中,msm8930_cdp_init中与display相关的是msm8930_init_fb()函数,这个函数注册了几个id为0的设备。各主要设备名如下,

“msm_fb” msm framebuffer设备,注意不是linux framebuffer设备,但是有对应关系;

“wfd” wifi显示设备;

“mipi_dsi_cmd_samsung_fwvga”  mipi-dsi接口cmd模式LCD屏设备;

“hdmi_msm” HDMI显示器设备;

“mdp” mobile display station显示引擎设备;

“mipi-dsi” MIPI-DSI显示器驱动设备(id例外用了1,可能有的平台两个MIPI-DSI,另外一个id为0);

1168void __init msm8930_init_fb(void) @ kernel/arch/arm/mach-msm/board-8930-display.c
1169{
1170	platform_device_register(&msm_fb_device);
1171
1172#ifdef CONFIG_FB_MSM_WRITEBACK_MSM_PANEL
1173	platform_device_register(&wfd_panel_device);
1174	platform_device_register(&wfd_device);
1175#endif
1176
1178#ifdef CONFIG_FB_MSM_MIPI_NOVATEK_CMD_QHD_PT
1179	platform_device_register(&mipi_dsi_novatek_panel_device);
1180#endif
1181
1184#ifdef CONFIG_FB_MSM_MIPI_SA77_CMD_FWVGA_PANEL
1185	platform_device_register(&mipi_dsi_cmd_chimei_fwvga_panel_device);
1186	platform_device_register(&mipi_dsi_cmd_samsung_fwvga_panel_device);
1187#endif
1189
1190#ifdef CONFIG_FB_MSM_HDMI_MSM_PANEL
1191	platform_device_register(&hdmi_msm_device);
1192#endif
1193
1194	platform_device_register(&mipi_dsi_toshiba_panel_device);
1195
1196	msm_fb_register_device("mdp", &mdp_pdata);
1197	msm_fb_register_device("mipi_dsi", &mipi_dsi_pdata);
1198#ifdef CONFIG_MSM_BUS_SCALING
1199#ifdef CONFIG_FB_MSM_DTV 
1200	msm_fb_register_device("dtv", &dtv_pdata);
1201#endif 
1202#endif
1203}

因为注册这些设备的意图主要是资源申请和初步初始化设备,所以各设备注册顺序并无关紧要。其初始化顺序还与后来的驱动实际注册顺序有关。

 

首先注册paltform_device msm_fb_device,该设备定义如下:

71static struct resource msm_fb_resources[] = {
72	{
73		.flags = IORESOURCE_DMA,
74	}
75}; 
135static struct msm_fb_platform_data msm_fb_pdata = http://blog.csdn.net/zirconsdu/article/details/{
136	.detect_client = msm_fb_detect_panel,
137};
138
139static struct platform_device msm_fb_device = {
140	.name   = "msm_fb",
141	.id     = 0,
142	.num_resources     = ARRAY_SIZE(msm_fb_resources),
143	.resource          = msm_fb_resources,
144	.dev.platform_data = &msm_fb_pdata,
145};

然后注册panel设备,定义如下:

845static struct mipi_dsi_panel_platform_data samsung_pdata = http://blog.csdn.net/zirconsdu/article/details/{
846	.enable_wled_bl_ctrl = 0x1,
847};
848
849static struct platform_device mipi_dsi_cmd_samsung_fwvga_panel_device = {
850	.name = "dsi_cmd_samsung_fwvga",
851	.id = 0,
852	.dev = {
853		.platform_data = &samsung_pdata,
854	}
855};

然后关键的注册mdp和mipi-dsi controller.

1749void __init msm_fb_register_device(char *name, void *data)
1750{
1751	if (!strncmp(name, "mdp", 3))
1752		msm_register_device(&msm_mdp_device, data);
1753	else if (!strncmp(name, "lcdc", 4))
1754		msm_register_device(&msm_lcdc_device, data);
1755	else if (!strncmp(name, "mipi_dsi", 8))
1756		msm_register_device(&msm_mipi_dsi_device, data);
1757#ifdef CONFIG_FB_MSM_TVOUT
1758	else if (!strncmp(name, "tvenc", 5))
1759		msm_register_device(&msm_tvenc_device, data);
1760	else if (!strncmp(name, "tvout_device", 12))
1761		msm_register_device(&msm_tvout_device, data);
1762#endif
1763#ifdef CONFIG_MSM_BUS_SCALING
1764	else if (!strncmp(name, "dtv", 3))
1765		msm_register_device(&msm_dtv_device, data);
1766#endif
1767	else
1768		printk(KERN_ERR "%s: unknown device! %s\n", __func__, name);
1769}

mdp和mipi-dsi设备及寄存器映射和中断需求如下

1484#define MIPI_DSI_HW_BASE	0x04700000
1485#define ROTATOR_HW_BASE	0x04E00000
1486#define TVENC_HW_BASE		0x04F00000
1487#define MDP_HW_BASE		0x05100000
1488
1489static struct resource msm_mipi_dsi_resources[] = {
1490	{
1491		.name   = "mipi_dsi",
1492		.start  = MIPI_DSI_HW_BASE,
1493		.end    = MIPI_DSI_HW_BASE + 0x000F0000 - 1,
1494		.flags  = IORESOURCE_MEM,
1495	},
1496	{
1497		.start  = DSI_IRQ,
1498		.end    = DSI_IRQ,
1499		.flags  = IORESOURCE_IRQ,
1500	},
1501};
1502
1503static struct platform_device msm_mipi_dsi_device = {
1504	.name   = "mipi_dsi",
1505	.id     = 1,
1506	.num_resources  = ARRAY_SIZE(msm_mipi_dsi_resources),
1507	.resource       = msm_mipi_dsi_resources,
1508};
1509
1510static struct resource msm_mdp_resources[] = {
1511	{
1512		.name   = "mdp",
1513		.start  = MDP_HW_BASE,
1514		.end    = MDP_HW_BASE + 0x000F0000 - 1,
1515		.flags  = IORESOURCE_MEM,
1516	},
1517	{
1518		.start  = INT_MDP,
1519		.end    = INT_MDP,
1520		.flags  = IORESOURCE_IRQ,
1521	},
1522};
1523
1524static struct platform_device msm_mdp_device = {
1525	.name   = "mdp",
1526	.id     = 0,
1527	.num_resources  = ARRAY_SIZE(msm_mdp_resources),
1528	.resource       = msm_mdp_resources,
1529};

以上设备注册时,其驱动并未加载,因为machine_desc.init_machine设备注册的arch_initcall是在.initcall3.init中,而module_init driver注册是在.initcall6.init中。等其驱动加载时,在对应的probe函数中,判断设备id,初步初始化设备,保存其资源分配。

此时,以下设备中id为0,mipi-dsi id为1的设备已经注册进系统了。

dsi_cmd_chimei_fwvga.0

dsi_cmd_samsung_fwvga.0

dsi_cmd_samsung_fwvga.1281

dtv.0

dtv.458753

hdmi_msm.0

hdmi_msm.1

 

mdp.0

mdp.458753

mdp.591105

mdp.655361

mipi_dsi.1

mipi_dsi.591105

mipi_toshiba.0

 

msm_fb.0

msm_fb.458753

msm_fb.591105

msm_fb.655361


 

下面描述各驱动注册,各驱动都是module_init的。

msm_fb驱动注册如下

module_init(msm_fb_init);
3898int __init msm_fb_init(void) @ kernel/drivers/video/msm/msm_fb.c
3899{
3900	int rc = -ENODEV;
3901
3902	if (msm_fb_register_driver())
3903		return rc;
	….
}
3705static int msm_fb_register_driver(void)
3706{
3707	return platform_driver_register(&msm_fb_driver);
3708}

msm_fb_driver驱动定义如下

734static struct platform_driver msm_fb_driver = {
735	.probe = msm_fb_probe,
736	.remove = msm_fb_remove,
737#ifndef CONFIG_HAS_EARLYSUSPEND
738	.suspend = msm_fb_suspend,
739	.resume = msm_fb_resume,
740#endif
741	.shutdown = NULL,
742	.driver = {
743		   /* Driver name must match the device name added in platform.c. */
744		   .name = "msm_fb",
745		   .pm = &msm_fb_dev_pm_ops,
746		   },
747};

platform_device “msm_fb”的resource[0]是一块DMA内存,是framebuffer内存,但是在资源定义中并没有设置size,而在msm_fb_probe中从其使用可以看到该DMA内存已经分配。其size是在machine的init_early中从bootmem中分配的,比machine级别设备注册要早!

                .init_early = msm8930_allocate_memory_regions,

msm8930_allocate_memory_regions(void) @ kernel/arch/arm/mach-msm/board-8930.c

1006static void __init msm8930_allocate_memory_regions(void)
1007{
1008	msm8930_allocate_fb_region();
1009}

msm8930_allocate_fb_region() @ kernel/arch/arm/mach-msm/board-8930-display.c

1205void __init msm8930_allocate_fb_region(void) 
1206{
1207	void *addr;
1208	unsigned long size;
1209
1210	size = MSM_FB_SIZE;
1211	addr = alloc_bootmem_align(size, 0x1000);
1212	msm_fb_resources[0].start = __pa(addr);
1213	msm_fb_resources[0].end = msm_fb_resources[0].start + size - 1;
1214	pr_info("allocating %lu bytes at %p (%lx physical) for fb\n", size, addr, __pa(addr));
1216}

MSM_FB_SIZE宏定义如下,TRIPLE_BUFFER已是主流;对应地SurfaceFlinger中FB layer也会分配有3个buffer。

32#ifdef CONFIG_FB_MSM_TRIPLE_BUFFER
33#define MSM_FB_PRIM_BUF_SIZE \
34		(roundup((1920 * 1088 * 4), 4096) * 3) /* 4 bpp x 3 pages */
35#else
36#define MSM_FB_PRIM_BUF_SIZE \
37		(roundup((1920 * 1088 * 4), 4096) * 2) /* 4 bpp x 2 pages */
38#endif
39/* Note: must be multiple of 4096 */
40#define MSM_FB_SIZE roundup(MSM_FB_PRIM_BUF_SIZE, 4096)

当”msm_fb”注册时,msm_fb_probe在设备和驱动match后被调用。对于msm_fb_device id=0, 只做fbram保存和ION client创建;这时probe到的设备对应/sys/bus/platform/devices /msm_fb.0。msm_ion_client_create(-1, pdev->name); ”mipi-dsi” driver定义和注册如下 (in kernel/drivers/video/msm/mipi_dsi.c)

55static struct platform_driver mipi_dsi_driver = {
56	.probe = mipi_dsi_probe,
57	.remove = mipi_dsi_remove,
58	.shutdown = NULL,
59	.driver = {
60		   .name = "mipi_dsi",
61		   },
62};
603static int mipi_dsi_register_driver(void)
604{
605	return platform_driver_register(&mipi_dsi_driver);
606}
607
608static int __init mipi_dsi_driver_init(void)
609{
610	int ret;
611
612	mipi_dsi_init();
613
614	ret = mipi_dsi_register_driver();
615
616	device_initialize(&dsi_dev);
617
618	if (ret) {
619		pr_err("mipi_dsi_register_driver() failed!\n");
620		return ret;
621	}
622
623	return ret;
624}
625
626module_init(mipi_dsi_driver_init);

“mdp” driver定义和注册如下(in kernel/drivers/video/msm/mdp.c)

2094static struct platform_driver mdp_driver = {
2095	.probe = mdp_probe,
2096	.remove = mdp_remove,
2097#ifndef CONFIG_HAS_EARLYSUSPEND
2098	.suspend = mdp_suspend,
2099	.resume = NULL,
2100#endif
2101	.shutdown = NULL,
2102	.driver = {
2103		/*
2104		 * Driver name must match the device name added in
2105		 * platform.c.
2106		 */
2107		.name = "mdp",
2108		.pm = &mdp_dev_pm_ops,
2109	},
2110};
3001static int mdp_register_driver(void)
3002{
3003#ifdef CONFIG_HAS_EARLYSUSPEND
3004	early_suspend.level = EARLY_SUSPEND_LEVEL_DISABLE_FB - 1;
3005	early_suspend.suspend = mdp_early_suspend;
3006	early_suspend.resume = mdp_early_resume;
3007	register_early_suspend(&early_suspend);
3008#endif
3009
3010	return platform_driver_register(&mdp_driver);
3011}
3012
3013static int __init mdp_driver_init(void)
3014{
3015	int ret;
3016
3017	mdp_drv_init();
3018
3019	ret = mdp_register_driver();
3020	if (ret) {
3021		printk(KERN_ERR "mdp_register_driver() failed!\n");
3022		return ret;
3023	}
3024
3025#if defined(CONFIG_DEBUG_FS)
3026	mdp_debugfs_init();
3027#endif
3028
3029	return 0;
3030
3031}
3032
3033module_init(mdp_driver_init);

当真正从屏驱动中添加一块显示设备时,为了让上级设备(“mipi-dsi” “mdp” “msm_fb” “fb”)使用下级设备,高通实现为下级设备创建了每个上级设备的实例,通过从下到上的设备probe链一级一级向上注册。这时保证从下到上的设备注册顺序就是至关重要的了,probe链做注册来保证这一点。

当然为了达到上级设备使用和管理下级设备的目标,另一种方法是下级设备向上级设备做register,这时要保证下级设备向上级设备注册时,上级设备的用于管理的相关数据结构已经准备好。

下面描述由屏驱动添加屏到注册linux framebuffer设备的流程。

在各自的屏设备注册文件中,会去探测屏,这种探测不是做真正扫描,仅仅是使用设备名字验证一下,以SAMSUNG MIPI DSI CMD屏为例,驱动会使用相应规则ID注册一块屏。

static int __init mipi_cmd_samsung_fwvga_pt_init(void) @ kernel/drivers/video/msm/mipi_samsung_cmd_fwvga_pt.c
{
37	int ret;
38
39	if (msm_fb_detect_client("mipi_cmd_samsung_fwvga"))
40		return 0;
	……
88	ret = mipi_samsung_device_register(&pinfo, MIPI_DSI_PRIM, MIPI_DSI_PANEL_QHD_PT);
90	if (ret)
91		pr_err("%s: failed to register device!\n", __func__);
92
93	return ret;
94}
95
96module_init(mipi_cmd_samsung_fwvga_pt_init);

探测函数int msm_fb_detect_client(const char *name)首先使用主屏和外屏名字匹配,匹配不成则使用msm_fd_device.dev.platform .detect_client = msm_fb_detect_panel去匹配。上面欲同时注册SAMSUNG和CHIMEI两块屏设备,当然不能同时detect_panel成功,使用GPIO管脚配置做了二次匹配。实际不同批次的手机可能用到两块屏中的一种。

然后mipi_samsung_device_register()(对CHIMEI则是mipi_chimei_device_register)注册屏驱动和屏设备。驱动定义和注册具体如下,

358static struct platform_driver this_driver = {
359	.probe  = mipi_samsung_lcd_probe,
360	.driver = {
361		.name   = "dsi_cmd_samsung_fwvga",
362	},
363};
364
365static struct msm_fb_panel_data samsung_panel_data = http://blog.csdn.net/zirconsdu/article/details/{
366	.on		= mipi_samsung_lcd_on,
367	.off		= mipi_samsung_lcd_off,
368	.set_backlight = mipi_samsung_set_backlight,
369};
373int mipi_samsung_device_register(struct msm_panel_info *pinfo, u32 channel, u32 panel)
375{
376	struct platform_device *pdev = NULL;
377	int ret;
378
379	if ((channel >= 3) || ch_used[channel])
380		return -ENODEV;
381
382	ch_used[channel] = TRUE;
383
384	ret = mipi_samsung_lcd_init();
385	if (ret) {
386		pr_err("mipi_samsung_lcd_init() failed with ret %u/n", ret);
387		return ret;
388	}
389
390	pdev = platform_device_alloc("dsi_cmd_samsung_fwvga", (panel << 8)|channel);
391	if (!pdev)
392		return -ENOMEM;
393
394	samsung_panel_data.panel_info = *pinfo;
395
396	ret = platform_device_add_data(pdev, &samsung_panel_data,
397		sizeof(samsung_panel_data));
398	if (ret) {
399		printk(KERN_ERR
400		  "%s: platform_device_add_data failed!/n", __func__);
401		goto err_device_put;
402	}
403
404	ret = platform_device_add(pdev);
405	if (ret) {
406		printk(KERN_ERR
407		  "%s: platform_device_register failed!/n", __func__);
408		goto err_device_put;
409	}
410
411	return 0;
412
413err_device_put:
414	platform_device_put(pdev);
415	return ret;
416}
417
418static int mipi_samsung_lcd_init(void)
419{
420
421	led_trigger_register_simple("bkl_trigger", &bkl_led_trigger);
422	pr_info("%s: SUCCESS (WLED TRIGGER)/n", __func__);
423	wled_trigger_initialized = 1;
424
425	mipi_dsi_buf_alloc(&samsung_tx_buf, DSI_BUF_SIZE);
426	mipi_dsi_buf_alloc(&samsung_rx_buf, DSI_BUF_SIZE);
427
428	return platform_driver_register(&this_driver);
429}

在mipi_samsung_lcd_init()中注册platform_driver屏驱动,然后分配注册platform_device屏设备;platform_data设置为msm_fb_panel_data向上传递参数并用于上级设备调用控制屏开关和背光。

屏设备注册后,platform_device和platform_driver match, 驱动的probe函数被调用,把参数一级一级向上带,用于设置上级设备参数,向上一级一级注册设备(“mipi-dsi”, “mdp”, “msm_fb”, “framebuffer”)。

一个类似的调用栈如下

------------[ cut here ]------------
WARNING: at /home/CORPUSERS/xp010548/myworkdroid/7x25a/LINUX/kernel/drivers/video/msm/msm_fb.c:1221 msm_fb_probe+0xf4/0xcbc()
msm_fb_probe
Modules linked in:
 [<c003fe0c>] (unwind_backtrace+0x0/0x12c) from [<c00adccc>] (warn_slowpath_common+0x4c/0x64)
 [<c00adccc>] (warn_slowpath_common+0x4c/0x64) from [<c00add64>] (warn_slowpath_fmt+0x2c/0x3c)
 [<c00add64>] (warn_slowpath_fmt+0x2c/0x3c) from [<c0223c44>] (msm_fb_probe+0xf4/0xcbc)
 [<c0223c44>] (msm_fb_probe+0xf4/0xcbc) from [<c026e624>] (platform_drv_probe+0x18/0x1c)
 [<c026e624>] (platform_drv_probe+0x18/0x1c) from [<c026d354>] (driver_probe_device+0x144/0x264)
 [<c026d354>] (driver_probe_device+0x144/0x264) from [<c026c78c>] (bus_for_each_drv+0x48/0x84)
 [<c026c78c>] (bus_for_each_drv+0x48/0x84) from [<c026d5d0>] (device_attach+0x74/0xa0)
 [<c026d5d0>] (device_attach+0x74/0xa0) from [<c026c5a4>] (bus_probe_device+0x24/0x40)
 [<c026c5a4>] (bus_probe_device+0x24/0x40) from [<c026b4c4>] (device_add+0x3f0/0x570)
 [<c026b4c4>] (device_add+0x3f0/0x570) from [<c026ec54>] (platform_device_add+0x13c/0x1a0)
 [<c026ec54>] (platform_device_add+0x13c/0x1a0) from [<c02264b4>] (mdp_probe+0x828/0x940)
 [<c02264b4>] (mdp_probe+0x828/0x940) from [<c026e624>] (platform_drv_probe+0x18/0x1c)
 [<c026e624>] (platform_drv_probe+0x18/0x1c) from [<c026d354>] (driver_probe_device+0x144/0x264)
 [<c026d354>] (driver_probe_device+0x144/0x264) from [<c026c78c>] (bus_for_each_drv+0x48/0x84)
 [<c026c78c>] (bus_for_each_drv+0x48/0x84) from [<c026d5d0>] (device_attach+0x74/0xa0)
 [<c026d5d0>] (device_attach+0x74/0xa0) from [<c026c5a4>] (bus_probe_device+0x24/0x40)
 [<c026c5a4>] (bus_probe_device+0x24/0x40) from [<c026b4c4>] (device_add+0x3f0/0x570)
 [<c026b4c4>] (device_add+0x3f0/0x570) from [<c026ec54>] (platform_device_add+0x13c/0x1a0)
 [<c026ec54>] (platform_device_add+0x13c/0x1a0) from [<c023db98>] (mipi_dsi_probe+0x514/0x5d0)
 [<c023db98>] (mipi_dsi_probe+0x514/0x5d0) from [<c026e624>] (platform_drv_probe+0x18/0x1c)
 [<c026e624>] (platform_drv_probe+0x18/0x1c) from [<c026d354>] (driver_probe_device+0x144/0x264)
 [<c026d354>] (driver_probe_device+0x144/0x264) from [<c026c78c>] (bus_for_each_drv+0x48/0x84)
 [<c026c78c>] (bus_for_each_drv+0x48/0x84) from [<c026d5d0>] (device_attach+0x74/0xa0)
 [<c026d5d0>] (device_attach+0x74/0xa0) from [<c026c5a4>] (bus_probe_device+0x24/0x40)
 [<c026c5a4>] (bus_probe_device+0x24/0x40) from [<c026b4c4>] (device_add+0x3f0/0x570)
 [<c026b4c4>] (device_add+0x3f0/0x570) from [<c026ec54>] (platform_device_add+0x13c/0x1a0)
 [<c026ec54>] (platform_device_add+0x13c/0x1a0) from [<c02223b8>] (msm_fb_add_device+0x150/0x1b4)
 [<c02223b8>] (msm_fb_add_device+0x150/0x1b4) from [<c051e830>] (mipi_himax_lcd_probe+0x38/0x108)
 [<c051e830>] (mipi_himax_lcd_probe+0x38/0x108) from [<c026e624>] (platform_drv_probe+0x18/0x1c)
 [<c026e624>] (platform_drv_probe+0x18/0x1c) from [<c026d354>] (driver_probe_device+0x144/0x264)
 [<c026d354>] (driver_probe_device+0x144/0x264) from [<c026c78c>] (bus_for_each_drv+0x48/0x84)
 [<c026c78c>] (bus_for_each_drv+0x48/0x84) from [<c026d5d0>] (device_attach+0x74/0xa0)
 [<c026d5d0>] (device_attach+0x74/0xa0) from [<c026c5a4>] (bus_probe_device+0x24/0x40)
 [<c026c5a4>] (bus_probe_device+0x24/0x40) from [<c026b4c4>] (device_add+0x3f0/0x570)
 [<c026b4c4>] (device_add+0x3f0/0x570) from [<c026ec54>] (platform_device_add+0x13c/0x1a0)
 [<c026ec54>] (platform_device_add+0x13c/0x1a0) from [<c02409ec>] (mipi_himax_device_register+0x7c/0xc0)
 [<c02409ec>] (mipi_himax_device_register+0x7c/0xc0) from [<c001ac34>] (mipi_cmd_himax_hvga_pt_init+0x148/0x180)
 [<c001ac34>] (mipi_cmd_himax_hvga_pt_init+0x148/0x180) from [<c0034388>] (do_one_initcall+0x94/0x164)
 [<c0034388>] (do_one_initcall+0x94/0x164) from [<c00083d8>] (kernel_init+0x98/0x144)
 [<c00083d8>] (kernel_init+0x98/0x144) from [<c003b0d0>] (kernel_thread_exit+0x0/0x8)
---[ end trace 65f8ea860415c051 ]---

下面考察设备probe链。

311static int __devinit mipi_samsung_lcd_probe(struct platform_device *pdev)
312{
	…..
338	current_pdev = msm_fb_add_device(pdev);
339
340	if (current_pdev) {
341		mfd = platform_get_drvdata(current_pdev);
342		if (!mfd)
343			return -ENODEV;
344		if (mfd->key != MFD_KEY)
345			return -EINVAL;
346
347		mipi  = &mfd->panel_info.mipi;
348
349		if (phy_settings != NULL)
350			mipi->dsi_phy_db = phy_settings;
351
352		if (dlane_swap)
353			mipi->dlane_swap = dlane_swap;
354	}
355	return 0;
356}

msm_fb_add_device做如下事情:

调用struct platform_device *msm_fb_device_alloc(struct msm_fb_panel_data *pdata, u32 type, u32 id)函数分配platform_device “mipi-dsi.type_devid”并设置其platform_data为msm_fb_panel_data。

以额外msm_fb_data_type结构分配framebuffer。

注册”mipi-dsi”设备platform_device_add(this_dev)。

“mipi-dsi”设备和驱动进行attach, match后,“mipi-dsi” driver的probe被调用到。

static int mipi_dsi_probe(struct platform_device *pdev) @ kernel/drivers/video/msm/mipi_dsi.c做如下事情(这次的设备ID是真正实例的了,不是1了):

分配”mdp”设备实例并设置其数据,设置”mipi-dsi”设备操作函数,用于向下操作一级一级设备;

继续设置linux framebuffer的参数;

根据屏分辨率设置mipi-dsi工作频率;

注册该”mdp”设备实例;

“mdp”设备和驱动进行attach, match后,“mdp” driver的probe被调用到。

static int mdp_probe(struct platform_device *pdev) @ kernel/drivers/video/msm/mdp.c

分配”msm_fb”实例并设置其数据;

配置”mdp”工作模式;

注册”msm_fb”实例;

“msm_fb”设备和驱动进行attach, match后,“msm_fb” driver的probe被调用到。

static int msm_fb_probe(struct platform_device *pdev) @ kernel/drivers/video/msm/msm_fb.c

调用msm_fb_register设置linux framebuffer并register_framebuffer。

至此,系统中相关设备如下:

dsi_cmd_chimei_fwvga.0

dsi_cmd_samsung_fwvga.0

dsi_cmd_samsung_fwvga.1281 -> mipi_dsi.591105 -> mdp.591105 -> msm_fb.591105 -> fbx

dtv.0

dtv.458753 -> mdp.458753 -> msm_fb.458753  -> fbx

hdmi_msm.0

hdmi_msm.1 -> mdp.655361 -> msm_fb.655361 -> fbx (hdmi)

mdp.0

mipi_dsi.1

mipi_toshiba.0

msm_fb.0

Framebuffer设备注册后,使用FBIOCPUT_VSCREEN或FBIOCPAN_DISPLAY,驱动都会使用msmfb_pan_display进行响应显示,由于涉及到MDP,另文分析。

[END]



 

 

编译:QC MSM平台显示屏Framebuffer设备注册过程

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