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clk: sunxi-ng: h6: Reparent CPUX during PLL CPUX rate change 

[ Upstream commit 7e91ed763d ]

While PLL CPUX clock rate change when CPU is running from it works in
vast majority of cases, now and then it causes instability. This leads
to system crashes and other undefined behaviour. After a lot of testing
(30+ hours) while also doing a lot of frequency switches, we can't
observe any instability issues anymore when doing reparenting to stable
clock like 24 MHz oscillator.

Fixes: 524353ea48 ("clk: sunxi-ng: add support for the Allwinner H6 CCU")
Reported-by: Chad Wagner <wagnerch42@gmail.com>
Link: https://forum.libreelec.tv/thread/27295-orange-pi-3-lts-freezes/
Tested-by: Chad Wagner <wagnerch42@gmail.com>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Link: https://lore.kernel.org/r/20231013181712.2128037-1-jernej.skrabec@gmail.com
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Jernej Skrabec 2023-10-13 20:17:12 +02:00 committed by Greg Kroah-Hartman
parent 9f11b2a026
commit 9708e5081c
1 changed files with 17 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/clk/sunxi-ng/ccu-sun50i-h6.c
View File

@ -1181,11 +1181,18 @@ static const u32 usb2_clk_regs[] = {
SUN50I_H6_USB3_CLK_REG,
};
static struct ccu_mux_nb sun50i_h6_cpu_nb = {
.common = &cpux_clk.common,
.cm = &cpux_clk.mux,
.delay_us = 1,
.bypass_index = 0, /* index of 24 MHz oscillator */
};
static int sun50i_h6_ccu_probe(struct platform_device *pdev)
{
void __iomem *reg;
int i, ret;
u32 val;
int i;
reg = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(reg))
@ -1252,7 +1259,15 @@ static int sun50i_h6_ccu_probe(struct platform_device *pdev)
val |= BIT(24);
writel(val, reg + SUN50I_H6_HDMI_CEC_CLK_REG);
return devm_sunxi_ccu_probe(&pdev->dev, reg, &sun50i_h6_ccu_desc);
ret = devm_sunxi_ccu_probe(&pdev->dev, reg, &sun50i_h6_ccu_desc);
if (ret)
return ret;
/* Reparent CPU during PLL CPUX rate changes */
ccu_mux_notifier_register(pll_cpux_clk.common.hw.clk,
&sun50i_h6_cpu_nb);
return 0;
}
static const struct of_device_id sun50i_h6_ccu_ids[] = {