On 1/23/2013 7:07 AM, Tivy, Robert wrote: >> -----Original Message----- >> From: Nori, Sekhar >> Sent: Tuesday, January 22, 2013 4:04 AM >> >> Rob, >> >> On 1/11/2013 5:53 AM, Robert Tivy wrote: >>> Added dsp clock definition, keyed to "davinci-rproc.0". >>> >>> Signed-off-by: Robert Tivy <rtivy@xxxxxx> >>> --- >>> arch/arm/mach-davinci/da850.c | 9 +++++++++ >>> 1 file changed, 9 insertions(+) >>> >>> diff --git a/arch/arm/mach-davinci/da850.c b/arch/arm/mach- >> davinci/da850.c >>> index 097fcb2..50107c5 100644 >>> --- a/arch/arm/mach-davinci/da850.c >>> +++ b/arch/arm/mach-davinci/da850.c >>> @@ -375,6 +375,14 @@ static struct clk sata_clk = { >>> .flags = PSC_FORCE, >>> }; >>> >>> +static struct clk dsp_clk = { >>> + .name = "dsp", >>> + .parent = &pll0_sysclk1, >>> + .domain = DAVINCI_GPSC_DSPDOMAIN, >>> + .lpsc = DA8XX_LPSC0_GEM, >>> + .flags = PSC_LRST, >>> +}; >>> + >>> static struct clk_lookup da850_clks[] = { >>> CLK(NULL, "ref", &ref_clk), >>> CLK(NULL, "pll0", &pll0_clk), >>> @@ -421,6 +429,7 @@ static struct clk_lookup da850_clks[] = { >>> CLK("spi_davinci.1", NULL, &spi1_clk), >>> CLK("vpif", NULL, &vpif_clk), >>> CLK("ahci", NULL, &sata_clk), >>> + CLK("davinci-rproc.0", NULL, &dsp_clk), >> >> Adding this clock node without the having the driver probed leads to >> kernel hang while booting. With CONFIG_DAVINCI_RESET_CLOCKS=n, the >> kernel boot fine. It looks like there is some trouble disabling the >> clock if it is not used. Can you please check this issue? >> >> Thanks, >> Sekhar > > Sekhar, > > Thankyou for trying that out. > > I discovered that the kernel boot hang is caused when trying to disable this clk during init, from within the function davinci_clk_disable_unused(). That function calls davinci_psc_config() which attempts to disable the DSP clock. Since this clk is enabled after reset, disabling it involves a state transition, and therefore the function must wait for GOSTAT[1] to be 0. For most peripherals this happens automatically, but for the DSP (and ARM, too), the DSP must execute the IDLE instruction to allow a clock enable->disable transition. Since this is bootup and there is no real program on the DSP yet, this doesn't happen. > > I was able to overcome this by adding PSC_FORCE to the clk->flags for dsp_clk. In fact, without PSC_FORCE I was not able to "rmmod davinci_remoteproc" since the firmware file that I'm loading did not execute IDLE. It feels like for davinci we should have a way to control the clk->flags' PSC_FORCE setting at run-time. The PSC_FORCE would be set initially (during boot) and the user (or system integrator) would have a way to unset it dynamically. That way, when the DSP firmware does actually have a structured way to enter IDLE, the user can say "I'd like a structured shutdown" and unset PSC_FORCE (via a clean API). But for now I'm just going to turn on PSC_FORCE: > .flags = PSC_LRST | PSC_FORCE, Thanks for the debug. It works for me after I added PSC_FORCE. Here is the patch I am finally committing. Thanks, Sekhar commit 09810a853b9a7920ba8c250d18815ef236effc47 Author: Robert Tivy <rtivy@xxxxxx> AuthorDate: Thu Jan 10 16:23:22 2013 -0800 Commit: Sekhar Nori <nsekhar@xxxxxx> CommitDate: Thu Jan 24 10:54:08 2013 +0530 ARM: davinci: da850: add dsp clock definition Added dsp clock definition, keyed to "davinci-rproc.0". DSP clocks is derived from pll0 sysclk1. Add a clock tree node for that too. Signed-off-by: Robert Tivy <rtivy@xxxxxx> [nsekhar@xxxxxx: merge addition of pll0 sysclk1 and dsp clock into one commit. Add PSC_FORCE to dsp clock node to handle the case where DSP does not go into IDLE and its clock needs to be disabled.] Signed-off-by: Sekhar Nori <nsekhar@xxxxxx> diff --git a/arch/arm/mach-davinci/da850.c b/arch/arm/mach-davinci/da850.c index 6b9154e..0c4a26d 100644 --- a/arch/arm/mach-davinci/da850.c +++ b/arch/arm/mach-davinci/da850.c @@ -76,6 +76,13 @@ static struct clk pll0_aux_clk = { .flags = CLK_PLL | PRE_PLL, }; +static struct clk pll0_sysclk1 = { + .name = "pll0_sysclk1", + .parent = &pll0_clk, + .flags = CLK_PLL, + .div_reg = PLLDIV1, +}; + static struct clk pll0_sysclk2 = { .name = "pll0_sysclk2", .parent = &pll0_clk, @@ -368,10 +375,19 @@ static struct clk sata_clk = { .flags = PSC_FORCE, }; +static struct clk dsp_clk = { + .name = "dsp", + .parent = &pll0_sysclk1, + .domain = DAVINCI_GPSC_DSPDOMAIN, + .lpsc = DA8XX_LPSC0_GEM, + .flags = PSC_LRST | PSC_FORCE, +}; + static struct clk_lookup da850_clks[] = { CLK(NULL, "ref", &ref_clk), CLK(NULL, "pll0", &pll0_clk), CLK(NULL, "pll0_aux", &pll0_aux_clk), + CLK(NULL, "pll0_sysclk1", &pll0_sysclk1), CLK(NULL, "pll0_sysclk2", &pll0_sysclk2), CLK(NULL, "pll0_sysclk3", &pll0_sysclk3), CLK(NULL, "pll0_sysclk4", &pll0_sysclk4), @@ -413,6 +429,7 @@ static struct clk_lookup da850_clks[] = { CLK("spi_davinci.1", NULL, &spi1_clk), CLK("vpif", NULL, &vpif_clk), CLK("ahci", NULL, &sata_clk), + CLK("davinci-rproc.0", NULL, &dsp_clk), CLK(NULL, NULL, NULL), }; -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html