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Vineet Gupta
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DC_CTRL.RGN_OP is 3 bits wide, however only 1 bit is used in current programming model (0: flush, 1: invalidate) The current code targetting 3 bits leads to additional 8 byte AND operation which can be elided given that only 1 bit is ever set by software and/or looked at by hardware before ------ | 80b63324 <__dma_cache_wback_inv_l1>: | 80b63324: clri r3 | 80b63328: lr r2,[dc_ctrl] | 80b6332c: and r2,r2,0xfffff1ff <--- 8 bytes insn | 80b63334: or r2,r2,576 | 80b63338: sr r2,[dc_ctrl] | ... | ... | 80b63360 <__dma_cache_inv_l1>: | 80b63360: clri r3 | 80b63364: lr r2,[dc_ctrl] | 80b63368: and r2,r2,0xfffff1ff <--- 8 bytes insn | 80b63370: bset_s r2,r2,0x9 | 80b63372: sr r2,[dc_ctrl] | ... | ... | 80b6338c <__dma_cache_wback_l1>: | 80b6338c: clri r3 | 80b63390: lr r2,[dc_ctrl] | 80b63394: and r2,r2,0xfffff1ff <--- 8 bytes insn | 80b6339c: sr r2,[dc_ctrl] after (AND elided totally in 2 cases, replaced with 2 byte BCLR in 3rd) ----- | 80b63324 <__dma_cache_wback_inv_l1>: | 80b63324: clri r3 | 80b63328: lr r2,[dc_ctrl] | 80b6332c: or r2,r2,576 | 80b63330: sr r2,[dc_ctrl] | ... | ... | 80b63358 <__dma_cache_inv_l1>: | 80b63358: clri r3 | 80b6335c: lr r2,[dc_ctrl] | 80b63360: bset_s r2,r2,0x9 | 80b63362: sr r2,[dc_ctrl] | ... | ... | 80b6337c <__dma_cache_wback_l1>: | 80b6337c: clri r3 | 80b63380: lr r2,[dc_ctrl] | 80b63384: bclr_s r2,r2,0x9 | 80b63386: sr r2,[dc_ctrl] Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.