{"id":2357,"date":"2017-12-31T14:25:50","date_gmt":"2017-12-31T06:25:50","guid":{"rendered":"http:\/\/learn-house.idv.tw\/?p=2357"},"modified":"2017-12-31T14:25:50","modified_gmt":"2017-12-31T06:25:50","slug":"%e6%8e%a7%e5%88%b6%e7%a1%ac%e9%ab%94","status":"publish","type":"post","link":"https:\/\/learn-house.idv.tw\/?p=2357","title":{"rendered":"\u63a7\u5236\u786c\u9ad4"},"content":{"rendered":"<p>\u8cc7\u6599\u4f86\u6e90\uff1ahttp:\/\/silverfoxkkk.pixnet.net\/blog\/post\/43026733-lddp%3A%E4%B8%83%E3%80%81%E6%8E%A7%E5%88%B6%E7%A1%AC%E9%AB%94<\/p>\n<p>\u4e03\u3001\u63a7\u5236\u786c\u9ad4<br \/>\n\u9a45\u52d5\u7a0b\u5f0f\u6700\u4e3b\u8981\u7684\u4efb\u52d9 &#8211; \u63a7\u5236\u786c\u9ad4\u3002<\/p>\n<p>7-1\u3001\u63a7\u5236\u786c\u9ad4<br \/>\n\u9a45\u52d5\u7a0b\u5f0f\u7684\u5de5\u4f5c\uff0c\u5c31\u662f\u5e6b\u52a9 kernel \u63a7\u5236\u786c\u9ad4\uff0ckernel \u5c07\u4e0d\u8a8d\u8b58\u7684\u786c\u9ad4\u4ea4\u7d66\u9a45\u52d5\u7a0b\u5f0f\u63a7\u5236\uff0c\u800c\u9a45\u52d5\u7a0b\u5f0f\u518d\u8207 kernel \u6e9d\u901a\u5f8c\uff0c\u5373\u53ef\u8b93 kernel \u8a8d\u8b58\u786c\u9ad4\uff0c\u5982\u6b64\uff0c user process \u5373\u53ef\u900f\u904e\u7cfb\u7d71\u547c\u53eb\u4ecb\u9762\u4f86\u64cd\u4f5c\u786c\u9ad4\u3002<\/p>\n<p>\u5404\u7a2e\u786c\u9ad4\u90fd\u6709\u7368\u7279\u7684\u63a7\u5236\u65b9\u5f0f\uff0c\u4f46\u5927\u591a\u6578\u786c\u9ad4\u90fd\u53ef\u900f\u904e\u9a45\u52d5\u7a0b\u5f0f\u8b80\u5beb\u300c\u66ab\u5b58\u5668\u300d\u4f86\u64cd\u63a7\u3002<br \/>\n\u66ab\u5b58\u5668\u662f\u786c\u9ad4(\u88dd\u7f6e)\u5167\u90e8\u7684\u8a18\u61b6\u7a7a\u9593\uff0c\u4f46\u5c6c\u65bc\u65b7\u96fb\u5f8c\u5167\u5bb9\u5c31\u6703\u6d88\u5931\u7684\u63ee\u767c\u6027\u8a18\u61b6\u9ad4\u3002<\/p>\n<p>\u9a45\u52d5\u7a0b\u5f0f\u9019\u985e\u8edf\u9ad4\u53bb\u8b80\u5beb\u88dd\u7f6e\u7684\u66ab\u5b58\u5668\uff0c\u4e5f\u5c31\u662f CPU \u53bb\u8b80\u5beb\u88dd\u7f6e\uff0c\u56e0\u70ba\u8edf\u9ad4\u662f\u5728 CPU \u4e0a\u9762\u904b\u884c\u7684\u3002<br \/>\n\u5177\u9ad4\u7684\u8b80\u5beb\u65b9\u5f0f\u96a8\u8457\u88dd\u7f6e\u800c\u6709\u4e0d\u540c\uff0c\u4e00\u822c\u4f86\u8aaa\u53ef\u6b78\u70ba\u300cI\/O mapped I\/O\u300d\u8207\u300cMemory mapped I\/O\u300d\u9019\u5169\u985e\u3002<\/p>\n<p><!--more--><\/p>\n<p>7-2\u3001I\/O Mapped I\/O<br \/>\n\u300cI\/O mapped I\/O\u300d\u6307\u7684\u662f\u7d93\u7531\u901a\u8a0a\u57e0\u8b80\u5beb\uff0c\u53ea\u662f\u70ba\u4e86\u8207\u300cMemory mapped I\/O\u300d\u5c0d\u61c9\uff0c\u624d\u5982\u6b64\u63cf\u8ff0\u3002<br \/>\n\u5f88\u4e45\u4ee5\u524d\u7684\u88dd\u7f6e\uff0c\u591a\u534a\u90fd\u5404\u81ea\u64c1\u6709 I\/O port(\u901a\u8a0a\u57e0)\uff0c\u9019\u662f\u7528\u4f86\u5c07\u8cc7\u6599\u5beb\u7d66\u786c\u9ad4\u3001\u6216\u662f\u5f9e\u786c\u9ad4\u8b80\u51fa\u8cc7\u6599\u7684\u4ecb\u9762\uff0c\u4ee3\u8868\u53ea\u6709\u786c\u9ad4\u64c1\u6709 I\/O port\uff0c\u5c31\u53ef\u4ee5\u7531\u9a45\u52d5\u7a0b\u5f0f\u900f\u904e I\/O port \u9032\u884c\u63a7\u5236\u3002<\/p>\n<p>\u70ba\u4e86\u901a\u4f5c I\/O port\uff0c\u7cfb\u7d71\u6e96\u5099\u4e86\u300cI\/O space\u300d\u9019\u500b\u7279\u5225\u7684\u7a7a\u9593\uff0c\u5b83\u8207 memory space(\u8a18\u61b6\u9ad4\u7a7a\u9593) \u662f\u5404\u81ea\u7368\u7acb\u7684\uff0cI\/O space \u88e1\u9762\u7684\u4f4d\u5740\u7a31\u70ba\u300cI\/O port space\u300d\u6216\u76f4\u7a31\u300cport\u300d\u3002<br \/>\n\u5404\u500b\u88dd\u7f6e\u90fd\u64c1\u6709\u81ea\u5df1\u7684 I\/O port address \u7bc4\u570d\uff0c\u786c\u9ad4\u8a2d\u8a08\u8005\u5fc5\u9808\u78ba\u4fdd\u7cfb\u7d71\u5167\u7684\u786c\u9ad4\u4e0d\u6703\u91cd\u8907\u7528\u5230\u540c\u4e00\u6bb5\u4f4d\u5740\u3002<br \/>\nLinux \u7684 I\/O port address \u5206\u914d\u72c0\u6cc1\u53ef\u900f\u904e\u300ccat \/proc\/ioports\u300d\u6307\u4ee4\u4f86\u67e5\u95b1\u3002<\/p>\n<p>I\/O port address \u7684\u8b80\u5beb\u65b9\u5f0f\u6709\u4e0b\u9762\u5e7e\u7a2e\uff1a<\/p>\n<ul>\n<li>\u4ee5 1 byte\u30012 bytes \u6216 4 bytes \u70ba\u55ae\u4f4d\u57f7\u884c\u8b80\u5beb<\/li>\n<\/ul>\n<p>\u56e0\u6b64\u5927\u91cf\u8cc7\u6599\u4e0d\u9069\u5408\u7d93\u7531 I\/O port \u50b3\u9001\uff0c\u53e6\u5916\u786c\u9ad4\u5982\u679c\u8981\u63d0\u4f9b I\/O port \u7684\u8a71\uff0c\u6703\u4f54\u7528\u5bf6\u8cb4\u7684\u96fb\u8def\u677f\u7a7a\u9593\uff0c\u6240\u4ee5\u6700\u8fd1\u7684\u786c\u9ad4\u591a\u534a\u5b8c\u5168\u4e0d\u900f\u904e I\/O port \u4f86\u901a\u8a0a\u3002<\/p>\n<p>\u70ba\u4e86\u8b93\u9a45\u52d5\u7a0b\u5f0f\u4e4b\u985e\u7684\u8edf\u9ad4\u53ef\u4ee5\u64cd\u4f5c I\/O port\uff0cCPU \u63d0\u4f9b\u4e86 I\/O port \u5c08\u7528\u7684 mnemonic(\u65b9\u4fbf\u8a18\u61b6\u7684\u7d44\u5408\u8a9e\u8a00\u6307\u4ee4\u5beb\u6cd5)\uff0c\u800c linux kernel \u70ba\u4e86\u8b93\u9a45\u52d5\u7a0b\u5f0f\u4e0d\u5fc5\u52d5\u7528\u7d44\u5408\u8a9e\u8a00\u6307\u4ee4\uff0c\u6240\u4ee5\u63d0\u4f9b\u4e86 C \u8a9e\u8a00\u53ef\u4ee5\u53d6\u7528\u7684\u51fd\u5f0f\uff0c\u9019\u4e9b\u51fd\u5f0f\u5b9a\u7fa9\u5728\u300casm\/io.h\u300d\u6a94\u6848\u5167\u3002<\/p>\n<table border=\"1\">\n<tbody>\n<tr>\n<td>\u51fd\u5f0f\u540d\u7a31<\/td>\n<td>\u529f\u80fd<\/td>\n<\/tr>\n<tr>\n<td>inb()<\/td>\n<td>\u5f9e port \u8b80\u51fa 1 byte<\/td>\n<\/tr>\n<tr>\n<td>inw()<\/td>\n<td>\u5f9e port \u8b80\u51fa 2 byte<\/td>\n<\/tr>\n<tr>\n<td>inl()<\/td>\n<td>\u5f9e port \u8b80\u51fa 4 byte<\/td>\n<\/tr>\n<tr>\n<td>outb()<\/td>\n<td>\u5f9e port \u5beb\u5165 1 byte<\/td>\n<\/tr>\n<tr>\n<td>outw()<\/td>\n<td>\u5f9e port \u5beb\u5165 2 byte<\/td>\n<\/tr>\n<tr>\n<td>outl()<\/td>\n<td>\u5f9e port \u5beb\u5165 4 byte<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u5728\u8b80\u5beb I\/O port \u7684\u6642\u5019\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u8fd1\u4f86 CPU \u7684\u6027\u80fd\u6108\u4f86\u6108\u9ad8\uff0c\u56e0\u6b64\u88dd\u7f6e\u6709\u53ef\u80fd\u8ddf\u4e0d\u4e0a CPU \u7684\u8655\u7406\u901f\u5ea6\uff0c\u56e0\u6b64 Linux \u6e96\u5099\u4e86\u6703\u7b49\u5f85\u7684\u51fd\u5f0f\uff0c\u672b\u5c3e\u7684 \u300cp\u300d \u5c31\u4ee3\u8868\u300cpause\u300d\u7684\u610f\u601d\uff1a<br \/>\nu8 inb_p(unsigned long port);<br \/>\nu16 inw_p(unsigned long port);<br \/>\nu32 inl_p(unsigned long port);<br \/>\nvoid outb_p(u8 b, unsigned long port);<br \/>\nvoid outw_p(u16 w, unsigned long port);<br \/>\nvoid outl_p(u32 l, unsigned long port);<\/p>\n<p>\u5982\u679c kernel \u8207\u597d\u5e7e\u500b\u9a45\u52d5\u7a0b\u5f0f\u540c\u6642\u4f7f\u7528\u540c\u4e00\u6bb5 I\/O port \u7684\u8a71\uff0c\u786c\u9ad4\u904b\u4f5c\u53ef\u80fd\u6703\u51fa\u554f\u984c\uff0c\u56e0\u6b64\uff0c\u8981\u8b80\u5beb I\/O port \u7684 module \u8981\u5148\u7528 request_region() \u628a\u4e00\u584a\u4f4d\u5740\u7a7a\u9593\u4fdd\u7559\u4e0b\u4f86\uff0c\u82e5\u4fdd\u7559\u6210\u529f\uff0c\u5c31\u6703\u5728 \/proc\/ioports \u986f\u793a\u9a45\u52d5\u7a0b\u5f0f\u7684\u540d\u7a31\uff1a<br \/>\nstruct resource *request_region(resource_size_t start, resource_size_t n, const char *name);<br \/>\nI\/O port \u7684\u958b\u59cb\u4f4d\u5740\u900f\u904e start \u5f15\u6578\u50b3\u5165\uff0c\u60f3\u8b80\u5beb\u7684 port \u500b\u6578\u5247\u900f\u904e n \u5f15\u6578\u50b3\u5165\uff0cname \u662f\u5728 \/proc\/ioports \u986f\u793a\u7684\u540d\u5b57\uff0c\u4e0d\u904e name \u5f15\u6578\u7684\u6307\u6a19\u6703\u88ab kernel \u7559\u8457\u4f7f\u7528\uff0c\u6240\u4ee5\u4e0d\u80fd\u50b3\u5165\u5340\u57df\u8b8a\u6578\u7684\u6307\u6a19\u3002<\/p>\n<p>\u53e6\u5916\uff0c\u4fdd\u7559 memory mapped I\/O (MMIO) \u4f4d\u5740\u7a7a\u9593\u7684\u51fd\u5f0f\u53eb\u505a request_mem_region()\u3002<\/p>\n<p>\u5728\u4e0d\u9700\u8981\u7528\u5230 I\/O port \u4e4b\u5f8c\uff0c\u4e00\u5b9a\u8981\u547c\u53eb release_region() \u91cb\u653e\u5148\u524d\u4fdd\u7559\u7684\u7a7a\u9593\uff0c\u5426\u5247\u5728\u5378\u8f09\u9a45\u52d5\u7a0b\u5f0f\u5f8c\uff0c\u76f4\u5230\u91cd\u958b\u6a5f\u4e4b\u5f8c\uff0c\u90fd\u7121\u6cd5\u518d\u4f7f\u7528\u9019\u584a I\/O port\uff1a<br \/>\nvoid release_region(resource_size_t start, resource_size_t n);<\/p>\n<p>7-3\u3001Memory Mapped I\/O<br \/>\n\u4ee5\u8a18\u61b6\u9ad4\u8b80\u5beb\u52d5\u4f5c\u4ee3\u66ff I\/O port \u5728\u786c\u9ad4\u5c64\u7d1a\u64cd\u7e31\u88dd\u7f6e\u7684\u624b\u6cd5\u5c31\u7a31\u70ba\u300cMemory Mapped I\/O\u300d(\u8a18\u61b6\u9ad4\u6620\u5c04\u8b80\u5beb)\uff0c\u7d93\u5e38\u7e2e\u5beb\u70ba\u300cMMIO\u300d\u3002<\/p>\n<p>\u9a45\u52d5\u7a0b\u5f0f\u53ea\u8981\u5411\u9810\u5148\u5b9a\u7fa9\u7684\u4f4d\u5740\u7bc4\u570d (MMIO\u7bc4\u570d) \u9032\u884c\u8b80\u5beb\u52d5\u4f5c\uff0c\u5c31\u6703\u8b8a\u6210\u5c0d\u7279\u5b9a\u786c\u9ad4\u8b80\u5beb\u66ab\u5b58\u5668\u7684\u52d5\u4f5c\u3002<br \/>\n\u4e5f\u56e0\u70ba\u53ea\u8981\u4ee5 C \u8a9e\u8a00\u7684\u6307\u6a19\u5c31\u80fd\u7c21\u55ae\u8fa6\u5230\uff0c\u6240\u4ee5\u6210\u70ba\u8fd1\u4ee3\u7684\u6a19\u6e96\u4f5c\u6cd5\u3002<\/p>\n<p>\u4e00\u822c\u5e38\u898b\u7684 IA-32 \u500b\u4eba\u96fb\u8166\u67b6\u69cb\u4e2d\uff0c\u662f\u628a\u7dca\u9130 4GB \u4ee5\u4e0b\u7684 1GB \u7bc4\u570d\u7576\u6210 MMIO \u7bc4\u570d\u3002<\/p>\n<p>\u8b80\u5beb MMIO \u7bc4\u570d\u6642\uff0c\u53ea\u8981\u7528\u6307\u6a19\u5c31\u53ef\u4ee5\u4e86\uff0c\u4f46\u662f\u4e0d\u80fd\u76f4\u63a5\u628a\u8a18\u61b6\u9ad4\u4f4d\u5740\u7684\u6578\u503c\u7576\u6210\u6307\u6a19\u4f86\u7528\uff0c\u5426\u5247\u53ef\u80fd\u6703\u9020\u6210\u300ckernel panic\u300d\u3002<br \/>\n\u56e0\u70ba\u9a45\u52d5\u7a0b\u5f0f\u662f\u5728\u865b\u64ec\u8a18\u61b6\u9ad4\u7a7a\u9593\u904b\u4f5c\u7684\u7de3\u6545\uff0c\u9019\u8ddf user space \u7684\u61c9\u7528\u7a0b\u5f0f\u8b80\u5beb\u4e0d\u6b63\u78ba\u7684\u8a18\u61b6\u9ad4\u4f4d\u5740\u800c\u5c0e\u81f4\u300csegmentation fault\u300d\u662f\u4e00\u6a23\u7684\u3002<\/p>\n<p>\u9a45\u52d5\u7a0b\u5f0f\u60f3\u8b80\u5beb MMIO \u7bc4\u570d\u6642\uff0c\u5fc5\u9808\u900f\u904e ioremap() \u628a\u7269\u7406\u4f4d\u5740\u6620\u5c04\u5230 kernel \u7684\u865b\u64ec\u8a18\u61b6\u9ad4\u7a7a\u9593\u624d\u884c\uff0c\u5b9a\u7fa9\u5728 \u300casm\/io.h\u300d\uff1a<br \/>\nvoid __iomem * ioremap(unsigned long offset, unsigned long size);<br \/>\noffset \u5f15\u6578\u662f\u7269\u7406\u8a18\u61b6\u9ad4\u4f4d\u5740\uff0csize \u5f15\u6578\u662f\u4ee5 byte \u55ae\u4f4d\u6307\u5b9a\u7684\u6620\u5c04\u7bc4\u570d\u5927\u5c0f\uff0cLinux kernel \u4e5f\u628a\u7269\u7406\u8a18\u61b6\u9ad4\u4f4d\u5740\u7a31\u70ba\u300cbus address\u300d\u3002<br \/>\n\u51fd\u5f0f\u57f7\u884c\u6210\u529f\u7684\u8a71\u6703\u50b3\u56de kernel \u7684\u865b\u64ec\u8a18\u61b6\u9ad4\u4f4d\u5740\uff0c\u5426\u5247\u50b3\u56de NULL\u3002<\/p>\n<p>\u900f\u904e ioremap() \u6620\u5c04\u7684\u52d5\u4f5c\uff0c\u5728\u67d0\u4e9b\u67b6\u69cb\u4e0a\u53ef\u80fd\u6703\u5c0e\u81f4\u554f\u984c\uff0c\u9019\u662f\u56e0\u70ba\u88ab cache \u5f71\u97ff\u7684\u7de3\u6545\u3002<br \/>\n\u9a45\u52d5\u7a0b\u5f0f\u5728\u8b80\u5beb\u4f4d\u65bc MMIO \u7bc4\u570d\u5167\u7684\u66ab\u5b58\u5668\u6642\uff0c\u6709\u6642\u6703\u5f9e cache \u8b80\u56de\u5148\u524d\u7684\u8cc7\u6599\uff0c\u800c\u4e0d\u6703\u771f\u5f97\u53bb\u8b80\u786c\u9ad4\uff0c\u5beb\u5165\u8cc7\u6599\u6642\u4e5f\u6703\u767c\u751f\u985e\u4f3c\u7684\u60c5\u5f62\uff0c\u56e0\u6b64\u64fe\u4e82 memory mapped I\/O \u7684\u5de5\u4f5c\u3002<br \/>\n\u9019\u6642\u5c31\u8981\u628a\u7528\u5230 ioremap() \u7684\u5730\u65b9\u6539\u7528 ioremap_nocache()\uff1a<br \/>\nvoid __iomem * ioremap_nocache(unsigned long phys_addr, unsigned long size);<\/p>\n<p>\u5728\u4e0d\u9700\u8981 memory mapped I\/O \u6642\uff0c\u9a45\u52d5\u7a0b\u5f0f\u5fc5\u9808\u547c\u53eb iounmap() \u660e\u78ba\u53d6\u6d88\u6620\u5c04\uff1a<br \/>\nvoid iounmap(volatile void __iomem *addr);<\/p>\n<p>\u9a45\u52d5\u7a0b\u5f0f\u7bc4\u4f8b\uff1a<br \/>\n#include<br \/>\n#include<br \/>\n#include<br \/>\n#include<\/p>\n<p>MODULE_LICENSE(&#8220;Dual BSD\/GPL&#8221;);<\/p>\n<p>static int sample_init(void) {<br \/>\nchar *reg;<br \/>\nprintk(KERN_ALERT &#8220;sample driver installed.\\n&#8221;);<\/p>\n<p>reg = ioremap_nocache(0xFEC00000, 4);<br \/>\nif (reg != NULL) {<br \/>\nprintk(KERN_ALERT &#8220;%x\\n&#8221;, *reg);<br \/>\niounmap(reg);<br \/>\n}<br \/>\nreturn 0;<br \/>\n}<\/p>\n<p>static void sample_exit(void) {<br \/>\nprintk(KERN_ALERT &#8220;sample driver removed.\\n&#8221;);<br \/>\n}<\/p>\n<p>module_init(sample_init);<br \/>\nmodule_exit(sample_exit);<\/p>\n<p>\u8b80\u5beb MMIO \u7bc4\u570d\u662f\u53ef\u4ee5\u76f4\u63a5 ioremap()\uff0c\u4f46\u70ba\u4e86\u907f\u514d\u885d\u7a81\uff0c\u9084\u662f\u5efa\u8b70\u4e8b\u5148\u5229\u7528 request_mem_region() \u4fdd\u7559\u4f4d\u5740\u7bc4\u570d\uff1a<br \/>\nstruct resource *request_mem_region(resource_size_t start, resource_size_t n, const char *name);<br \/>\nstart \u5f15\u6578\u662f MMIO \u7bc4\u570d\u958b\u982d\u7684\u7269\u7406\u8a18\u61b6\u9ad4\u4f4d\u5740\uff0cn\u5f15\u6578\u5247\u662f byte \u55ae\u4f4d\u7684\u7bc4\u570d\u5927\u5c0f\uff0cname \u662f\u5f15\u6578\u88dd\u7f6e\u540d\u7a31\uff0c\u51fd\u5f0f\u547c\u53eb\u6210\u529f\u5f8c\uff0c\u6703\u56de\u50b3 resource \u7d50\u69cb\u7684\u6307\u6a19\uff0c\u5426\u5247\u50b3\u56de NULL\u3002<br \/>\n\u4fdd\u7559\u6210\u529f\u5f8c\uff0c\u5c31\u80fd\u5728 \/proc\/iomem \u770b\u5230\u88dd\u7f6e\u540d\u7a31\u3002<br \/>\n\u5728\u4e0d\u9700\u8981\u8b80\u5beb MMIO \u7bc4\u570d\u5f8c\uff0c\u547c\u53eb iounmap() \u89e3\u9664\u6620\u5c04\u5f8c\uff0c\u9084\u9700\u8981\u547c\u53eb release_mem_region \u53d6\u6d88\u4fdd\u7559\uff1a<br \/>\nvoid release_mem_region(resource_size_t start, resource_size_t n);<br \/>\nstart \u5f15\u6578\u8ddf request_mem_region() \u540c\u6a23\u662f MMIO \u7bc4\u570d\u958b\u982d\u7684\u7269\u7406\u8a18\u61b6\u9ad4\u4f4d\u5740\uff0cn\u5f15\u6578\u5247\u662f byte \u55ae\u4f4d\u7684\u5927\u5c0f\u3002<\/p>\n<p>7-4\u3001PCI \u88dd\u7f6e\u7684\u6cdb\u7528\u4ecb\u9762<br \/>\n\u8b80\u5beb PCI \u88dd\u7f6e\u7684\u66ab\u5b58\u5668\u6642\uff0c\u53ef\u4ee5\u900f\u904e I\/O port \u4e5f\u53ef\u4ee5\u900f\u904e MIMO\uff0c\u6bcf\u500b\u88dd\u7f6e\u90fd\u53ef\u80fd\u4f7f\u7528\u4e0d\u540c\u7684\u8b80\u5beb\u65b9\u5f0f\uff0c\u63a7\u5236\u9019\u4e9b\u88dd\u7f6e\u7684\u9a45\u52d5\u7a0b\u5f0f\u5fc5\u9808\u6839\u64da\u88dd\u7f6e\u4f86\u5207\u63db\u8b80\u5beb\u65b9\u5f0f\u3002<br \/>\n\u5982\u6b64\u6703\u8b93\u9a45\u52d5\u7a0b\u5f0f\u7684\u5de5\u4f5c\u8b8a\u5f97\u66f4\u8907\u96dc\uff0c\u6240\u4ee5 Linux \u63d0\u4f9b\u4e86\u4e0d\u5fc5\u5340\u5206 I\/O port \u8207 MMIO \u7684\u62bd\u8c61\u4ecb\u9762 pci_iomap()\uff0c\u5b9a\u7fa9\u5728\u300casm\/iomap.h\u300d\uff1a<br \/>\nvoid __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen);<br \/>\n\u547c\u53eb\u5f8c\u6703\u81ea\u52d5\u5207\u63db I\/O port \u6216 MMIO \u8b80\u5beb\u65b9\u5f0f\uff0c\u4e26\u50b3\u56de\u6307\u5b9a BAR(Base Address Register) \u7684 kernel \u865b\u64ec\u4f4d\u5740\u3002<br \/>\n\u9700\u8981\u900f\u7530 I\/O port \u8b80\u5beb\u6642\uff0c\u5167\u90e8\u6703\u7528 ioport_map() \u9032\u884c\u6620\u5c04\uff0c\u4f7f\u5b83\u80fd\u8ddf MMIO \u900f\u904e\u540c\u6a23\u7684\u65b9\u5f0f\u8b80\u5beb\u3002<\/p>\n<p>\u4e0d\u9700\u8981\u8b80\u5beb\u5f8c\uff0c\u8981\u547c\u53eb pci_iounmap() \u89e3\u9664\u6620\u5c04\uff1a<br \/>\nvoid pci_iounmap(struct pci_dev *dev, void __iomem *addr);<\/p>\n<p>\u800c\u900f\u904e pci_iomap() \u6620\u5c04\u7684\u4f4d\u5740\u8b80\u5beb\u66ab\u5b58\u5668\u6642\uff0c\u5fc5\u9808\u4f7f\u7528\u5c08\u7528\u7684\u51fd\u5f0f\uff0c\u4e00\u6a23\u662f\u5b9a\u7fa9\u5728\u300casm\/io.h\u300d\uff1a<br \/>\nunsigned int ioread8(void __iomem *addr);<br \/>\nunsigned int ioread16(void __iomem *addr);<br \/>\nunsigned int ioread32(void __iomem *addr);<br \/>\nunsigned int iowrite8(u8 b, void __iomem *addr);<br \/>\nunsigned int iowrite16(u16 b, void __iomem *addr);<br \/>\nunsigned int iowrite32(u32 b, void __iomem *addr);<br \/>\n\u9019\u4e9b\u51fd\u5f0f\u6703\u5224\u65b7\u5c0d\u8c61\u662f I\/O port \u9084\u662f MMIO\uff0c\u4e26\u914d\u5408\u505a\u9069\u7576\u7684\u8655\u7406\u3002<\/p>\n<p>7-5\u3001\u4ee5 sparse \u505a\u975c\u614b\u7a0b\u5f0f\u78bc\u6aa2\u67e5<br \/>\n\u524d\u9762\u4ecb\u7d39\u7684\u51fd\u5f0f prototype \u591a\u534a\u90fd\u6709\u300c__iomem\u300d\u7684\u6a19\u8a18\uff0c\u67e5\u770b\u6a19\u982d\u6a94\u5b9a\u7fa9\uff1a<br \/>\n#ifdef __CHECKER__<br \/>\n# define __iomem __attribute__((noderef, address_space(2)))<br \/>\n#else<br \/>\n# define __iomem<br \/>\n#endif<\/p>\n<p>\u5e73\u5e38\u7de8\u8b6f\u9a45\u52d5\u7a0b\u5f0f\u6642\uff0c\u6c92\u6709\u5b9a\u7fa9 __CHECKER__\uff0c\u56e0\u6b64 __iomem \u9019\u500b\u5de8\u96c6\u7684\u5167\u5bb9\u662f\u7a7a\u7684\uff0c\u9019\u500b\u5de8\u96c6\u8981\u5728\u900f\u904e sparse \u9019\u500b\u975c\u614b\u7a0b\u5f0f\u78bc\u6aa2\u67e5\u5de5\u5177\u6aa2\u67e5\u7a0b\u5f0f\u78bc\u6642\u624d\u6703\u8d77\u4f5c\u7528\u3002<br \/>\n__iomem \u5de8\u96c6\u6703\u900f\u904e gcc \u64f4\u5145\u529f\u80fd\u6307\u5b9a\u4e0b\u5217\u5c6c\u6027\uff1a<\/p>\n<ul>\n<li>\u4e0d\u80fd\u900f\u904e *(\u89e3\u53c3\u8003\u904b\u7b97\u5b50)\u5b58\u53d6\u6307\u6a19(noderef)<\/li>\n<li>\u4f4d\u65bc I\/O \u4f4d\u5740\u7a7a\u9593 (I\/O mapped I\/O \u6216 memory mapped I\/O; address_space(2))<\/li>\n<\/ul>\n<p>address_space() \u62ec\u5f27\u5167\u7684\u6578\u5b57\u610f\u7fa9\uff1a<\/p>\n<table border=\"1\">\n<tbody>\n<tr>\n<td>\u6578\u503c<\/td>\n<td>\u610f\u7fa9<\/td>\n<\/tr>\n<tr>\n<td>0<\/td>\n<td>Kernel space<\/td>\n<\/tr>\n<tr>\n<td>1<\/td>\n<td>User space<\/td>\n<\/tr>\n<tr>\n<td>2<\/td>\n<td>I\/O space<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>sparse \u5b89\u88dd\u5b8c\u6210\u5f8c\uff0c\u5c31\u53ef\u4ee5\u5efa\u69cb\u9a45\u52d5\u7a0b\u5f0f\uff0c\u4ee5\u5f80\u90fd\u662f\u5728\u547d\u4ee4\u5217\u57f7\u884c\u300cmake\u300d\uff0c\u73fe\u5728\u8981\u591a\u6307\u5b9a\u300cC=1\u300d\u6216\u300cC=2\u300d\uff0c\u300cC=1\u300d\u6703\u6aa2\u67e5\u9700\u8981\u91cd\u65b0\u7de8\u8b6f\u7684\u6a94\u6848\uff0c\u300cC=2\u300d\u5247\u6703\u6aa2\u67e5\u6240\u6709\u7684\u6a94\u6848\u3002<\/p>\n<p>\u5728\u57f7\u884c \u300cmake C=2\u300d\u7de8\u8b6f 7-3 \u7684\u7bc4\u4f8b\u7a0b\u5f0f\u5f8c\uff0c\u6703\u51fa\u73fe\u4e9b\u8a31 warning\uff0c\u9700\u4fee\u6539\u7a0b\u5f0f\u78bc\u5982\u4e0b\uff1a<br \/>\nchar *reg; =&gt;\u00a0char __iomem *reg;<br \/>\nprintk(KERN_ALERT &#8220;%x\\n&#8221;, *reg); =&gt;\u00a0printk(KERN_ALERT &#8220;%x\\n&#8221;, ioread8(reg));<\/p>\n<p>7-6\u3001\u8a18\u61b6\u9ad4\u5c4f\u969c<br \/>\nC\u8a9e\u8a00\u7684\u7a0b\u5f0f\u88ab\u7de8\u8b6f\u5668\u8f49\u6210\u7d44\u5408\u8a9e\u8a00\uff0c\u6700\u5f8c\u8f49\u6210\u6a5f\u68b0\u8a9e\u8a00\u624d\u80fd\u5728 CPU \u4e0a\u57f7\u884c\uff0c\u800c\u7de8\u8b6f\u5668\u70ba\u4e86\u63d0\u6607\u7a0b\u5f0f\u57f7\u884c\u7684\u6548\u7387\uff0c\u6709\u6642\u6703\u4ea4\u63db\u6307\u4ee4\u7684\u57f7\u884c\u9806\u5e8f\u3002<\/p>\n<p>\u4f46\u9032\u9019\u7a2e\u8abf\u63db\u6cd5\u5c0d\u9a45\u52d5\u7a0b\u5f0f\u4f86\u8aaa\u537b\u5f88\u6709\u554f\u984c\uff0c\u5728\u4f7f\u7528 MMIO \u8b80\u5beb\u66ab\u5b58\u5668\u6642\uff0c\u53ef\u80fd\u6703\u9020\u6210\u610f\u5916\u7684\u884c\u70ba\uff0c\u5982\u540c\u4e4b\u524d\u63d0\u904e\uff0cMMIO \u662f\u900f\u904e\u6307\u6a19\u53bb\u5b58\u53d6\u88dd\u7f6e\u7684\u66ab\u5b58\u5668\uff0c\u4f46\u7de8\u8b6f\u5668\u53ea\u770b\u6307\u6a19\u5b58\u53d6\u52d5\u4f5c\u800c\u5df2\u3002<\/p>\n<p>\u6bd4\u5982\u8aaa\u5728\u6e96\u5099\u57f7\u884c DMA (Direct Memory Access) \u6642\uff0c\u9a45\u52d5\u7a0b\u5f0f\u5e38\u6703\u7528\u5230\u4e0b\u9762\u9019\u7a2e\u5beb\u6cd5\uff1a<br \/>\n*a = ptr;\u00a0\/* \u628a buffer \u7684\u4f4d\u5740\u5beb\u5165\u66ab\u5b58\u5668 *\/<br \/>\n*b = len;\u00a0\/* \u628a buffer \u5bb9\u91cf\u5beb\u5165\u66ab\u5b58\u5668 *\/<br \/>\n*c = 1;\u00a0\/* \u958b\u59cb DMA *\/<br \/>\n\u5148\u628a buffer \u6e96\u5099\u597d\u5f8c\uff0c\u518d\u900f\u904e\u66ab\u5b58\u5668\u555f\u52d5 DMA\uff0c\u4e00\u5b9a\u8981\u5230\u6700\u5f8c\u624d\u80fd\u5beb\u5165\u300c*c\u300d\uff0c\u4f46\u5982\u679c\u7d93\u904e\u7de8\u8b6f\u5668\u7684\u8abf\u63db\uff1a<br \/>\n*b = len;\u00a0\/* \u628a buffer \u5bb9\u91cf\u5beb\u5165\u66ab\u5b58\u5668 *\/<br \/>\n*c = 1;\u00a0\/* \u958b\u59cb DMA *\/<br \/>\n*a = ptr;\u00a0\/* \u628a buffer \u7684\u4f4d\u5740\u5beb\u5165\u66ab\u5b58\u5668 *\/<br \/>\n\u5247\u6703\u9020\u6210\u5728 buffer \u9084\u6c92\u6e96\u5099\u597d\u7684\u60c5\u5f62\u4e0b\u958b\u59cb DMA\uff0c\u6709\u53ef\u80fd\u8b93\u7cfb\u7d71\u7576\u6389\u3002<\/p>\n<p>\u70ba\u4e86\u61c9\u7528\u9019\u7a2e\u60c5\u5f62\uff0c kernel \u63d0\u4f9b\u4e86\u300c Memory Barrier\u300d(\u8a18\u61b6\u9ad4\u5c4f\u969c) \u7684\u6a5f\u5236\u3002<\/p>\n<p>barrier()<br \/>\nbarrier() \u5de8\u96c6\u6703\u63d2\u5165 memory barrier\uff0cgcc \u4e0d\u6703\u628a\u6307\u4ee4\u79fb\u904e memory barrier\u3002<\/p>\n<p>wmb()<br \/>\nwmb (Write Memory Barrier) \u662f\u4f7f\u8a18\u61b6\u9ad4\u5beb\u5165\u9806\u5e8f\u7dad\u6301\u8207 C \u539f\u59cb\u78bc\u4e00\u81f4\u7684\u5de8\u96c6\u3002<\/p>\n<p>rmb()<br \/>\nrmb (Read Memory Barrier) \u80fd\u4fdd\u8a3c\u5728\u9019\u884c\u4e4b\u524d\u7684\u300c\u8a18\u61b6\u9ad4\u8b80\u53d6\u5de5\u4f5c\u300d\u5df2\u7d93\u5168\u90e8\u57f7\u884c\u5b8c\u6210\u3002<\/p>\n<p>mb()<br \/>\nmb (Memory Barrier) \u9019\u500b\u5de8\u96c6\u540c\u6642\u5177\u5099 wmb() \u8207 rmb() \u7684\u529f\u80fd\u3002<\/p>\n<p>7-7\u3001volatile<br \/>\nC\u8a9e\u8a00\u7684\u8cc7\u6599\u578b\u614b\u6709\u300cvolatile(\u63ee\u767c\u6027)\u300d\u9019\u9ebc\u4e00\u500b\u4fee\u98fe\u8a5e\uff0c\u70ba\u8b8a\u6578\u52a0\u4e0a volatile \u4fee\u98fe\u8a5e\uff0c\u53ef\u4ee5\uff1a<\/p>\n<ul>\n<li>\u9632\u6b62\u8a18\u61b6\u9ad4\u5b58\u53d6\u52d5\u4f5c\u7684\u6700\u4f73\u5316<\/li>\n<li>\u9632\u6b62\u522a\u9664\u8a18\u61b6\u9ad4\u5b58\u53d6\u52d5\u4f5c<\/li>\n<\/ul>\n<p>\u5177\u9ad4\u4f8b\u5b50\uff1a<br \/>\n#include<\/p>\n<p>int main(void) {<br \/>\nint val, n;<br \/>\nint *p;<\/p>\n<p>val = 2008;<br \/>\np = &amp;val;<br \/>\nn = *p;<\/p>\n<p>printf(&#8220;%d\\n&#8221;, val);<br \/>\nreturn 0;<br \/>\n}<\/p>\n<p>\u9019\u500b\u4f8b\u5b50\u628a *p \u6307\u6a19\u5411\u5411\u7684\u503c\u5b58\u5230 n \u4e4b\u5167\uff0c\u4f46\u662f\u537b\u6c92\u7528\u5230 n \u8b8a\u6578\uff0c\u56e0\u4e9b\u7de8\u8b6f\u5668\u53ef\u80fd\u6703\u628a\u5b58\u5165 n \u7684\u52d5\u4f5c\u522a\u9664\uff0c\u4f46\u5982\u679c *p \u6307\u6a19\u662f MMIO \u4f4d\u5740\u7684\u8a71\uff0c\u6216\u8a31\u9019\u4ee3\u8868\u300c\u5f9e\u88dd\u7f6e\u8b80\u53d6\u66ab\u5b58\u5668\u5167\u5bb9\u300d\u7684\u52d5\u4f5c\uff0c\u65bc\u662f\u5c11\u6389\u9019\u500b\u52d5\u4f5c\u7684\u8a71\uff0c\u786c\u9ad4\u53ef\u80fd\u5c31\u4e0d\u6703\u4e00\u5982\u9810\u60f3\u5730\u904b\u4f5c\uff0c\u6240\u4ee5\u8981\u5728 MMIO \u7684\u6307\u6a94\u8b8a\u6578\u8981\u52a0\u4e0a \u300cvolatile\u300d\u624d\u884c\uff1a<br \/>\nvolatile int *p<\/p>\n<p>\u53e6\u4e00\u500b\u4f8b\u5b50\uff1a<br \/>\n#include<\/p>\n<p>int main(void) {<br \/>\nint val, n;<br \/>\nint *p;<\/p>\n<p>val = 2008;<br \/>\np = &amp;val;<br \/>\nn = *p;<br \/>\nn = *p;<br \/>\nn = *p;<\/p>\n<p>printf(&#8220;%d\\n&#8221;, val);<br \/>\nreturn 0;<br \/>\n}<br \/>\n\u9019\u500b\u4f8b\u5b50\u9023\u7e8c\u4e09\u6b21\u5beb\u5165 n \u8b8a\u6578\uff0c\u7de8\u8b6f\u5668\u6700\u4f73\u5316\u6642\uff0c\u53ef\u80fd\u628a\u9019\u4e9b\u5beb\u5165\u52d5\u4f5c\u6574\u5408\u6210\u4e00\u500b\uff0c\u4f46\u5982\u679c *p \u662f MMIO \u4f4d\u5740\u7684\u8a71\uff0c\u5c31\u53ef\u80fd\u9020\u6210\u554f\u984c\uff0c\u56e0\u6b64 *p \u6307\u6a19\u8b8a\u6578\u61c9\u8a72\u8981\u52a0\u4e0a volatile \u624d\u5c0d\u3002<\/p>\n<p>\u7de8\u8b6f\u5668\u6709\u6c92\u6709\u7522\u751f\u9069\u5207\u7684\u7d44\u5408\u8a9e\u8a00\u78bc\uff0c\u53ef\u4ee5\u900f\u904e\u300cgcc -S\u300d\u4f86\u6aa2\u8996\u7d44\u5408\u8a9e\u8a00\u78bc(*.s)\u4f86\u5224\u65b7\u3002<\/p>\n<p>7-8\u3001\u884c\u5167\u7d44\u8b6f<br \/>\n\u6709\u6642\u5149\u9760 C \u8a9e\u8a00\u7121\u6cd5\u63a7\u5236\u786c\u9ad4\uff0c\u9084\u662f\u9700\u8981\u8b93\u7d44\u5408\u8a9e\u8a00\u4e0a\u5834\uff0c\u672c\u7bc0\u5c31\u5728\u8aaa\u660e C \u8a9e\u8a00\u539f\u59cb\u78bc\u5167\u64b0\u5beb\u7d44\u5408\u8a9e\u8a00\u7684\u65b9\u5f0f\u3002<\/p>\n<p>asm \u95dc\u9375\u5b57<br \/>\n\u5728 C \u8a9e\u8a00\u7684\u539f\u59cb\u78bc\u5167\u63d2\u5165\u7d44\u5408\u8a9e\u8a00\u539f\u59cb\u78bc\u7684\u52d5\u4f5c\u7a31\u70ba\u300cInline assembler(\u884c\u5167\u7d44\u8b6f)\u300d\uff0c\u800c\u884c\u5167\u7d44\u8b6f\u7684\u95dc\u9375\u5b57\u662f\u300casm\u300d\u3002<br \/>\nasm \u95dc\u9375\u5b57\u7684\u8a9e\u8a00\u5982\u4e0b\uff1a<br \/>\nasm(&#8220;\u7d44\u5408\u8a9e\u8a00\u6307\u4ee4\u78bc&#8221;<br \/>\n: \u8f38\u51fa\u66ab\u5b58\u5668<br \/>\n: \u8f38\u5165\u66ab\u5b58\u5668<br \/>\n: \u6703\u8b8a\u66f4\u7684\u66ab\u5b58\u5668<\/p>\n<p>\u6aa2\u67e5\u7d44\u5408\u8a9e\u8a00\u78bc<br \/>\n\u8981\u6aa2\u67e5\u7522\u751f\u7684\u7d44\u5408\u8a9e\u8a00\u78bc\u6b63\u78ba\u8207\u5426\u7684\u8a71\uff0c\u53ef\u4fee\u6539\u9a45\u52d5\u7a0b\u5f0f\u7684 Makefile \uff0c\u5728 CFLAGS \u9078\u9805\u52a0\u4e0a\u300c-S\u300d\u3002<\/p>\n<p>\u7a0d\u5fae\u8907\u96dc\u7684 asm \u95dc\u9375\u5b57<\/p>\n<p>7-9\u3001\u7d50\u8a9e<br \/>\n\u63a7\u5236\u786c\u9ad4\u662f\u9a45\u52d5\u7a0b\u5f0f\u7684\u4e3b\u8981\u5de5\u4f5c\uff0c\u57fa\u672c\u4e0a\u900f\u904e\u6307\u6a19\u8b80\u5beb\u786c\u9ad4\u7684\u66ab\u5b58\u5668\u5c31\u884c\u4e86\uff0c\u4f46\u662f\u7de8\u8b6f\u5668\u5728\u6700\u4f73\u5316\u6642\u6709\u4e00\u4e9b\u9677\u9631\uff0c\u958b\u767c\u6642\u5fc5\u9808\u7279\u5225\u6ce8\u610f\u9019\u4e9b\u60c5\u5f62\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u8cc7\u6599\u4f86\u6e90\uff1ahttp:\/\/silverfoxkkk.pixnet.net\/blog\/post\/43026733-<span class=\"post-excerpt-end\">&hellip;<\/span><\/p>\n<p class=\"more-link\"><a href=\"https:\/\/learn-house.idv.tw\/?p=2357\" class=\"themebutton\">Read More<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[],"class_list":["post-2357","post","type-post","status-publish","format-standard","hentry","category-8"],"_links":{"self":[{"href":"https:\/\/learn-house.idv.tw\/index.php?rest_route=\/wp\/v2\/posts\/2357","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/learn-house.idv.tw\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/learn-house.idv.tw\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/learn-house.idv.tw\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/learn-house.idv.tw\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2357"}],"version-history":[{"count":0,"href":"https:\/\/learn-house.idv.tw\/index.php?rest_route=\/wp\/v2\/posts\/2357\/revisions"}],"wp:attachment":[{"href":"https:\/\/learn-house.idv.tw\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2357"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/learn-house.idv.tw\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2357"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/learn-house.idv.tw\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2357"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}