From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Walmsley Subject: [PATCHv2 06/12] ARM: OMAP2+: hwmod: add flag to prevent hwmod code from touching IP block during init Date: Sun, 10 Jun 2012 18:46:11 -0600 Message-ID: <20120611004608.20034.55965.stgit@dusk> References: <20120611004502.20034.8840.stgit@dusk> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from utopia.booyaka.com ([72.9.107.138]:42569 "EHLO utopia.booyaka.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751968Ab2FKAwK (ORCPT ); Sun, 10 Jun 2012 20:52:10 -0400 In-Reply-To: <20120611004502.20034.8840.stgit@dusk> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: =?utf-8?q?Beno=C3=AEt?= Cousson Add HWMOD_EXT_OPT_MAIN_CLK flag to indicate that this IP block is dependent on an off-chip functional clock that is not guaranteed to be present during initialization. IP blocks marked with this flag are left in the INITIALIZED state during kernel init. This is a workaround for a hardware problem. It should be possible to guarantee that at least one clock source will be present and active for any IP block's main functional clock. This ensures that the hwmod code can enable and reset the IP block. Resetting the IP block during kernel init prevents any bogus bootloader, ROM code, or previous OS configuration from affecting the kernel. Hopefully a clock multiplexer can be added on future SoCs. N.B., at some point in the future, it should be possible to query the clock framework for this type of information. Then this flag should no longer be needed. Signed-off-by: Paul Walmsley Cc: Beno=C3=AEt Cousson --- arch/arm/mach-omap2/omap_hwmod.c | 3 +++ arch/arm/plat-omap/include/plat/omap_hwmod.h | 6 ++++++ 2 files changed, 9 insertions(+) diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/oma= p_hwmod.c index d27bf48..e0b8131 100644 --- a/arch/arm/mach-omap2/omap_hwmod.c +++ b/arch/arm/mach-omap2/omap_hwmod.c @@ -2140,6 +2140,9 @@ static int __init _setup_reset(struct omap_hwmod = *oh) if (oh->_state !=3D _HWMOD_STATE_INITIALIZED) return -EINVAL; =20 + if (oh->flags & HWMOD_EXT_OPT_MAIN_CLK) + return -EPERM; + if (oh->rst_lines_cnt =3D=3D 0) { r =3D _enable(oh); if (r) { diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/pl= at-omap/include/plat/omap_hwmod.h index 2c53648..b5f3efc 100644 --- a/arch/arm/plat-omap/include/plat/omap_hwmod.h +++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h @@ -417,6 +417,11 @@ struct omap_hwmod_omap4_prcm { * running on the chip (e.g., the MPU is in idle). For such modul= es, * fine-grained PM runtime-based idle control is simply a waste of * CPU cycles. + * HWMOD_EXT_OPT_MAIN_CLK: The only main functional clock source for + * this IP block comes from an off-chip source and is not always + * enabled. This prevents the hwmod code from being able to + * enable and reset the IP block early. XXX Eventually it should + * be possible to query the clock framework for this information. */ #define HWMOD_SWSUP_SIDLE (1 << 0) #define HWMOD_SWSUP_MSTANDBY (1 << 1) @@ -428,6 +433,7 @@ struct omap_hwmod_omap4_prcm { #define HWMOD_CONTROL_OPT_CLKS_IN_RESET (1 << 7) #define HWMOD_16BIT_REG (1 << 8) #define HWMOD_ALWAYS_FORCE_SIDLE (1 << 9) +#define HWMOD_EXT_OPT_MAIN_CLK (1 << 10) =20 /* * omap_hwmod._int_flags definitions -- To unsubscribe from this list: send the line "unsubscribe linux-omap" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: paul@pwsan.com (Paul Walmsley) Date: Sun, 10 Jun 2012 18:46:11 -0600 Subject: [PATCHv2 06/12] ARM: OMAP2+: hwmod: add flag to prevent hwmod code from touching IP block during init In-Reply-To: <20120611004502.20034.8840.stgit@dusk> References: <20120611004502.20034.8840.stgit@dusk> Message-ID: <20120611004608.20034.55965.stgit@dusk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Add HWMOD_EXT_OPT_MAIN_CLK flag to indicate that this IP block is dependent on an off-chip functional clock that is not guaranteed to be present during initialization. IP blocks marked with this flag are left in the INITIALIZED state during kernel init. This is a workaround for a hardware problem. It should be possible to guarantee that at least one clock source will be present and active for any IP block's main functional clock. This ensures that the hwmod code can enable and reset the IP block. Resetting the IP block during kernel init prevents any bogus bootloader, ROM code, or previous OS configuration from affecting the kernel. Hopefully a clock multiplexer can be added on future SoCs. N.B., at some point in the future, it should be possible to query the clock framework for this type of information. Then this flag should no longer be needed. Signed-off-by: Paul Walmsley Cc: Beno?t Cousson --- arch/arm/mach-omap2/omap_hwmod.c | 3 +++ arch/arm/plat-omap/include/plat/omap_hwmod.h | 6 ++++++ 2 files changed, 9 insertions(+) diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c index d27bf48..e0b8131 100644 --- a/arch/arm/mach-omap2/omap_hwmod.c +++ b/arch/arm/mach-omap2/omap_hwmod.c @@ -2140,6 +2140,9 @@ static int __init _setup_reset(struct omap_hwmod *oh) if (oh->_state != _HWMOD_STATE_INITIALIZED) return -EINVAL; + if (oh->flags & HWMOD_EXT_OPT_MAIN_CLK) + return -EPERM; + if (oh->rst_lines_cnt == 0) { r = _enable(oh); if (r) { diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/plat-omap/include/plat/omap_hwmod.h index 2c53648..b5f3efc 100644 --- a/arch/arm/plat-omap/include/plat/omap_hwmod.h +++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h @@ -417,6 +417,11 @@ struct omap_hwmod_omap4_prcm { * running on the chip (e.g., the MPU is in idle). For such modules, * fine-grained PM runtime-based idle control is simply a waste of * CPU cycles. + * HWMOD_EXT_OPT_MAIN_CLK: The only main functional clock source for + * this IP block comes from an off-chip source and is not always + * enabled. This prevents the hwmod code from being able to + * enable and reset the IP block early. XXX Eventually it should + * be possible to query the clock framework for this information. */ #define HWMOD_SWSUP_SIDLE (1 << 0) #define HWMOD_SWSUP_MSTANDBY (1 << 1) @@ -428,6 +433,7 @@ struct omap_hwmod_omap4_prcm { #define HWMOD_CONTROL_OPT_CLKS_IN_RESET (1 << 7) #define HWMOD_16BIT_REG (1 << 8) #define HWMOD_ALWAYS_FORCE_SIDLE (1 << 9) +#define HWMOD_EXT_OPT_MAIN_CLK (1 << 10) /* * omap_hwmod._int_flags definitions