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authorRoger Quadros <rogerq@ti.com>2013-12-08 18:39:02 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-12-20 07:34:21 -0800
commit2c64388e8bde7f654167ac2dca485e9545dd6915 (patch)
treef6e9951dae967c2c04e1c418f221658712077edc
parent8670ef4f9748ce81ffb4454a4b41b3b548a39b20 (diff)
ARM: OMAP2+: hwmod: Fix SOFTRESET logic
commit 313a76ee11cda6700548afe68499ef174a240688 upstream. In _ocp_softreset(), after _set_softreset() + write_sysconfig(), the hwmod's sysc_cache will always contain SOFTRESET bit set so all further writes to sysconfig using this cache will initiate a repeated SOFTRESET e.g. enable_sysc(). This is true for OMAP3 like platforms that have RESET_DONE status in the SYSSTATUS register and so the the SOFTRESET bit in SYSCONFIG is not automatically cleared. It is not a problem for OMAP4 like platforms that indicate RESET completion by clearing the SOFTRESET bit in the SYSCONFIG register. This repeated SOFTRESET is undesired and was the root cause of USB host issues on OMAP3 platforms when hwmod was allowed to do the SOFTRESET for the USB Host module. To fix this we clear the SOFTRESET bit and update the sysconfig register + sysc_cache using write_sysconfig(). Signed-off-by: Roger Quadros <rogerq@ti.com> Tested-by: Tomi Valkeinen <tomi.valkeinen@ti.com> # Panda, BeagleXM [paul@pwsan.com: renamed _clr_softreset() to _clear_softreset()] Signed-off-by: Paul Walmsley <paul@pwsan.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/arm/mach-omap2/omap_hwmod.c43
1 files changed, 42 insertions, 1 deletions
diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 7144ae651d3d..bb7ed98ab9af 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -317,7 +317,7 @@ static int _set_clockactivity(struct omap_hwmod *oh, u8 clockact, u32 *v)
}
/**
- * _set_softreset: set OCP_SYSCONFIG.CLOCKACTIVITY bits in @v
+ * _set_softreset: set OCP_SYSCONFIG.SOFTRESET bit in @v
* @oh: struct omap_hwmod *
* @v: pointer to register contents to modify
*
@@ -1378,6 +1378,36 @@ static int _read_hardreset(struct omap_hwmod *oh, const char *name)
}
/**
+ * _clear_softreset: clear OCP_SYSCONFIG.SOFTRESET bit in @v
+ * @oh: struct omap_hwmod *
+ * @v: pointer to register contents to modify
+ *
+ * Clear the SOFTRESET bit in @v for hwmod @oh. Returns -EINVAL upon
+ * error or 0 upon success.
+ */
+static int _clear_softreset(struct omap_hwmod *oh, u32 *v)
+{
+ u32 softrst_mask;
+
+ if (!oh->class->sysc ||
+ !(oh->class->sysc->sysc_flags & SYSC_HAS_SOFTRESET))
+ return -EINVAL;
+
+ if (!oh->class->sysc->sysc_fields) {
+ WARN(1,
+ "omap_hwmod: %s: sysc_fields absent for sysconfig class\n",
+ oh->name);
+ return -EINVAL;
+ }
+
+ softrst_mask = (0x1 << oh->class->sysc->sysc_fields->srst_shift);
+
+ *v &= ~softrst_mask;
+
+ return 0;
+}
+
+/**
* _ocp_softreset - reset an omap_hwmod via the OCP_SYSCONFIG bit
* @oh: struct omap_hwmod *
*
@@ -1420,6 +1450,12 @@ static int _ocp_softreset(struct omap_hwmod *oh)
ret = _set_softreset(oh, &v);
if (ret)
goto dis_opt_clks;
+
+ _write_sysconfig(v, oh);
+ ret = _clear_softreset(oh, &v);
+ if (ret)
+ goto dis_opt_clks;
+
_write_sysconfig(v, oh);
if (oh->class->sysc->srst_udelay)
@@ -1918,6 +1954,11 @@ int omap_hwmod_softreset(struct omap_hwmod *oh)
goto error;
_write_sysconfig(v, oh);
+ ret = _clear_softreset(oh, &v);
+ if (ret)
+ goto error;
+ _write_sysconfig(v, oh);
+
error:
return ret;
}