From mboxrd@z Thu Jan 1 00:00:00 1970 From: York Sun Date: Thu, 2 Jan 2014 15:47:11 -0800 Subject: [U-Boot] [PATCH][v4] powerpc/mpc85xx: Add support for single source clocking In-Reply-To: <1387270552-13888-1-git-send-email-Priyanka.Jain@freescale.com> References: <1387270552-13888-1-git-send-email-Priyanka.Jain@freescale.com> Message-ID: <52C5FA7F.4090103@freescale.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 12/17/2013 12:55 AM, Priyanka Jain wrote: > Single-source clocking is new feature introduced in T1040. > In this mode, a single differential clock is supplied to the > DIFF_SYSCLK_P/N inputs to the processor, which in turn is > used to supply clocks to the sysclock, ddrclock and usbclock. > > So, both ddrclock and syclock are driven by same differential > sysclock in single-source clocking mode whereas in normal clocking > mode, generally separate DDRCLK and SYSCLK pins provides > reference clock for sysclock and ddrclock > > DDR_REFCLK_SEL rcw bit is used to determine DDR clock source > -If DDR_REFCLK_SEL rcw bit is 0, then DDR PLLs are driven in > normal clocking mode by DDR_Reference clock > > -If DDR_REFCLK_SEL rcw bit is 1, then DDR PLLs are driven in > single source clocking mode by DIFF_SYSCLK > > Add code to determine ddrclock based on DDR_REFCLK_SEL rcw bit. > > Signed-off-by: Poonam Aggrwal > Signed-off-by: Priyanka Jain > --- > Changes for v4: > Updated README with CONFIG_SYS_FSL_SINGLE_SOURCE_CLK > description. > > Changes for v3: > Incorporated York's comment to move declaration to > beginning of function. > > Changes for v2: > Incorporated York's comment to separate out > DDR_CLK_FREQ and SINGLE_SOURCE_CLK code > Applied to u-boot-mpc85xx/master. Thanks. York