diff mbox

[U-Boot,v2] sunxi: Add CONFIG_OLD_SUNXI_KERNEL_COMPAT Kconfig option

Message ID 1414053653-7352-1-git-send-email-hdegoede@redhat.com
State Accepted
Headers show

Commit Message

Hans de Goede Oct. 23, 2014, 8:40 a.m. UTC 
Add a Kconfig option which users can select when they want to boot older
kernels, e.g. the linux-sunxi 3.4 kernels. For now this just forces the pll5
"p" value to 1 (divide by 2) as that is what those kernels are hardcoded too,
in the future this may enable further workarounds.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
--
Changes in v2:
-s/CONFIG_OLD_KERNEL_COMPAT/CONFIG_OLD_SUNXI_KERNEL_COMPAT.
-Move the code block setting P(1) for old kernels to where P gets cleared
---
 arch/arm/cpu/armv7/sunxi/dram.c | 4 ++++
 board/sunxi/Kconfig             | 7 +++++++
 2 files changed, 11 insertions(+)

Comments

Tom Rini Oct. 23, 2014, 1:14 p.m. UTC | #1 
On Thu, Oct 23, 2014 at 10:40:53AM +0200, Hans de Goede wrote:

> Add a Kconfig option which users can select when they want to boot older
> kernels, e.g. the linux-sunxi 3.4 kernels. For now this just forces the pll5
> "p" value to 1 (divide by 2) as that is what those kernels are hardcoded too,
> in the future this may enable further workarounds.
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Reviewed-by: Tom Rini <trini@ti.com>
diff mbox

Patch

diff --git a/arch/arm/cpu/armv7/sunxi/dram.c b/arch/arm/cpu/armv7/sunxi/dram.c
index 0cbcf57..3cf3cbf 100644
--- a/arch/arm/cpu/armv7/sunxi/dram.c
+++ b/arch/arm/cpu/armv7/sunxi/dram.c
@@ -262,6 +262,10 @@  static void mctl_setup_dram_clock(u32 clk, u32 mbus_clk)
 	reg_val &= ~CCM_PLL5_CTRL_K_MASK;		/* set K to 0 (x1) */
 	reg_val &= ~CCM_PLL5_CTRL_N_MASK;		/* set N to 0 (x0) */
 	reg_val &= ~CCM_PLL5_CTRL_P_MASK;		/* set P to 0 (x1) */
+#ifdef CONFIG_OLD_SUNXI_KERNEL_COMPAT
+	/* Old kernels are hardcoded to P=1 (divide by 2) */
+	reg_val |= CCM_PLL5_CTRL_P(1);
+#endif
 	if (clk >= 540 && clk < 552) {
 		/* dram = 540MHz */
 		reg_val |= CCM_PLL5_CTRL_M(CCM_PLL5_CTRL_M_X(2));
diff --git a/board/sunxi/Kconfig b/board/sunxi/Kconfig
index 121d7d0..fb650c0 100644
--- a/board/sunxi/Kconfig
+++ b/board/sunxi/Kconfig
@@ -20,6 +20,13 @@  config SYS_SOC
 config FDTFILE
 	string "Default fdtfile env setting for this board"
 
+config OLD_SUNXI_KERNEL_COMPAT
+	boolean "Enable workarounds for booting old kernels"
+	default n
+	---help---
+	Set this to enable various workarounds for old kernels, this results in
+	sub-optimal settings for newer kernels, only enable if needed.
+
 config MMC0_CD_PIN
 	string "Card detect pin for mmc0"
 	default ""