linux-4.4.1/ioremap_nocache()(x86) の履歴(No.1)

• 履歴一覧
• 差分 を表示
• 現在との差分 を表示
• ソース を表示
• linux-4.4.1/ioremap_nocache()(x86) へ行く。
  • 1 (2016-02-24 (水) 13:02:47)

参照元†

• linux-4.4.1/ioremap_nocache()

説明†

• パス: [[linux-4.4.1/]]

• FIXME: これは何？
  • 説明

引数†

• phys_addr_t offset
  • linux-4.4.1/phys_addr_t
• size_t size
  • linux-4.4.1/size_t

返り値†

• void __iomem *

参考†

実装†

/**
 * ioremap_nocache     -   map bus memory into CPU space
 * @phys_addr:    bus address of the memory
 * @size:      size of the resource to map
 *
 * ioremap_nocache performs a platform specific sequence of operations to
 * make bus memory CPU accessible via the readb/readw/readl/writeb/
 * writew/writel functions and the other mmio helpers. The returned
 * address is not guaranteed to be usable directly as a virtual
 * address.
 *
 * This version of ioremap ensures that the memory is marked uncachable
 * on the CPU as well as honouring existing caching rules from things like
 * the PCI bus. Note that there are other caches and buffers on many
 * busses. In particular driver authors should read up on PCI writes
 *
 * It's useful if some control registers are in such an area and
 * write combining or read caching is not desirable:
 *
 * Must be freed with iounmap.
 */
void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size)
{
        /*
         * Ideally, this should be:
         *      pat_enabled() ? _PAGE_CACHE_MODE_UC : _PAGE_CACHE_MODE_UC_MINUS;
         *
         * Till we fix all X drivers to use ioremap_wc(), we will use
         * UC MINUS. Drivers that are certain they need or can already
         * be converted over to strong UC can use ioremap_uc().
         */
        enum page_cache_mode pcm = _PAGE_CACHE_MODE_UC_MINUS;

• • linux-4.4.1/page_cache_mode

        return __ioremap_caller(phys_addr, size, pcm,
                                __builtin_return_address(0));

• • linux-4.4.1/__ioremap_caller()

• linux-4.4.1/__builtin_return_address()

}
EXPORT_SYMBOL(ioremap_nocache);

• • linux-4.4.1/EXPORT_SYMBOL()

コメント†