> -----Original Message----- > From: Edward L Swarthout > Sent: Saturday, July 02, 2016 3:14 AM > To: Prabhakar Kushwaha <prabhakar.kushw...@nxp.com>; york sun > <york....@nxp.com>; Qianyu Gong <qianyu.g...@nxp.com>; > albert.u.b...@aribaud.net; u-boot@lists.denx.de; > s.temerkha...@gmail.com; yamada.masah...@socionext.com > Cc: Mingkai Hu <mingkai...@nxp.com> > Subject: RE: [U-Boot] [PATCH] armv8: Enable CPUECTLR.SMPEN for data > coherency > > From: Prabhakar Kushwaha > > >> From: U-Boot [mailto:u-boot-boun...@lists.denx.de] On Behalf Of york > >> On 06/30/2016 02:03 AM, Gong Qianyu wrote: > >> > From: Mingkai Hu <mingkai...@nxp.com> > >> > > >> > Data coherency is enabled only when the CPUECTLR.SMPEN bit is set. > >> > The SMPEN bit should be set before enabling the data cache. > >> > If not enabled, the cache is not coherent with other cores and data > >> > corruption could occur. > >> > > >> > + /* Enalbe SMPEN bit */ > >> > + mrs x0, S3_1_c15_c2_1 /* cpuactlr_el1 */ > >> > + orr x0, x0, #0x40 > >> > + msr S3_1_c15_c2_1, x0 > >> > + > >> > >> I wonder what impact this patch has. Did you find it effective on A53 core? > >> According to ARM documents, A57 and A72 seem don't care this bit. > > > >I have seen big difference on LS1012A with A53 cores after enabling this bit. > >If I don't enable this bit many IPs like SATA, SDHC show coherency issue. > > But LS1012A only has a single A53 core. > The multicore part, LS1043A, sets this bit in the bootrom: > > 34: d539f221 mrs x1, s3_1_c15_c2_1 > 38: b27a0021 orr x1, x1, #0x40 > 3c: d519f221 msr s3_1_c15_c2_1, x1 >
Bootrom team was under same impression like this bit not required for LS1012A. Hence they missed it. But as per Table 4-125 present in A53 TRM r0p4. This bit is required for hardware coherency. " Set the SMPEN bit before enabling the caches, even if there is only one core in the system." --prabhakar _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
