Never mind, I figured it out. I haven't rigorously tested it yet but the
/dev/hwrng node is populated and produces data as expected.
I'm attaching a patch if anyone's interested.
On Tuesday, August 19, 2014 12:46:47 PM UTC-5, James Johnson wrote:
>
>
> Hello BeagleBoard mailing list. Long time listener, first time caller.
>
> I've been trying to enable the AM335x onboard TRNG in the v3.8 kernel
> without much success. I've built a kernel using the TI SDK source, which is
> based on a v3.12 kernel, and the HWNRG works fine so I know it's not a
> problem with the chip.
>
> Porting the driver over requires enabling support for the RNG's clock in
> the 3.8 kernel. I've tried using the patches described here:
> http://lists.infradead.org/pipermail/linux-arm-kernel/2013-August/195546.html
> but these make the system hang on boot. It hangs too early for the kernel
> to print error messages, so unfortunately I don't have any to provide.
>
> I have noticed that am33xx clock data is handled in device tree in v3.12,
> while it's handled in hwmod in v3.8 (not sure if that's the correct way to
> put it).
>
> Anyone have any ideas? I'm pretty new to kernel hacking with this
> platform, and I'm still trying to grok the relationship between hwmod and
> device tree.
>
--
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diff --git a/arch/arm/boot/dts/am33xx.dtsi b/arch/arm/boot/dts/am33xx.dtsi
index 168dc7a..d5c1670 100644
--- a/arch/arm/boot/dts/am33xx.dtsi
+++ b/arch/arm/boot/dts/am33xx.dtsi
@@ -693,5 +693,12 @@
compatible = "ti,am335x-bandgap";
reg = <0x44e10448 0x8>;
};
+
+ rng: rng@48310 {
+ compatible = "ti,omap4-rng";
+ ti,hwmods = "rng";
+ reg = <0x4831 0x2000>;
+ interrupts = <111>;
+ };
};
};
diff --git a/arch/arm/mach-omap2/cclock33xx_data.c b/arch/arm/mach-omap2/cclock33xx_data.c
index c028220..b761210 100644
--- a/arch/arm/mach-omap2/cclock33xx_data.c
+++ b/arch/arm/mach-omap2/cclock33xx_data.c
@@ -421,6 +421,10 @@ static struct clk aes0_fck;
DEFINE_STRUCT_CLK_HW_OMAP(aes0_fck, NULL);
DEFINE_STRUCT_CLK(aes0_fck, dpll_core_ck_parents, clk_ops_null);
+static struct clk rng_fck;
+DEFINE_STRUCT_CLK_HW_OMAP(rng_fck, NULL);
+DEFINE_STRUCT_CLK(rng_fck, dpll_core_ck_parents, clk_ops_null);
+
/*
* Modules clock nodes
*
@@ -1151,6 +1155,7 @@ static struct omap_clk am33xx_clks[] = {
CLK(NULL, "smartreflex1_fck", &smartreflex1_fck, CK_AM33XX),
CLK(NULL, "sha0_fck", &sha0_fck, CK_AM33XX),
CLK(NULL, "aes0_fck", &aes0_fck, CK_AM33XX),
+CLK(NULL, "rng_fck", &rng_fck, CK_AM33XX),
CLK(NULL, "timer1_fck", &timer1_fck, CK_AM33XX),
CLK(NULL, "timer2_fck", &timer2_fck, CK_AM33XX),
CLK(NULL, "timer3_fck", &timer3_fck, CK_AM33XX),
diff --git a/arch/arm/mach-omap2/devices.c b/arch/arm/mach-omap2/devices.c
index a6d8070..8c05b95 100644
--- a/arch/arm/mach-omap2/devices.c
+++ b/arch/arm/mach-omap2/devices.c
@@ -471,8 +471,10 @@ static void omap_init_rng(void)
struct platform_device *pdev;
oh = omap_hwmod_lookup("rng");
- if (!oh)
+ if (!oh){
+ pr_err("Could not lookup rng hwmod\n");
return;
+ }
pdev = omap_device_build("omap_rng", -1, oh, NULL, 0, NULL, 0, 0);
WARN(IS_ERR(pdev), "Can't build omap_device for omap_rng\n");
@@ -631,9 +633,10 @@ static int __init omap2_init_devices(void)
omap_init_mcspi();
omap_init_sham();
omap_init_aes();
+ omap_init_rng();
}
omap_init_sti();
- omap_init_rng();
+
omap_init_vout();
omap_init_ocp2scp();
if (soc_is_am33xx()) {
diff --git a/arch/arm/mach-omap2/omap_hwmod_33xx_data.c b/arch/arm/mach-omap2/omap_hwmod_33xx_data.c
index 6e80edb..ee13d1e 100644
--- a/arch/arm/mach-omap2/omap_hwmod_33xx_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_33xx_data.c
@@ -3452,6 +3452,52 @@ static struct omap_hwmod_ocp_if am33xx_l3_main__aes0 = {
.user = OCP_USER_MPU | OCP_USER_SDMA,
};
+/* rng */
+static struct omap_hwmod_class_sysconfig am33xx_rng_sysc = {
+ .rev_offs= 0x1fe0,
+ .sysc_offs= 0x1fe4,
+ .sysc_flags= SYSC_HAS_AUTOIDLE | SYSC_HAS_SIDLEMODE,
+ .idlemodes= SIDLE_FORCE | SIDLE_NO,
+ .sysc_fields= &omap_hwmod_sysc_type1,
+ };
+
+ static struct omap_hwmod_class am33xx_rng_hwmod_class = {
+ .name= "rng",
+ .sysc= &am33xx_rng_sysc,
+ };
+
+ static struct omap_hwmod am33xx_rng_hwmod = {
+ .name= "rng"
