linux-kernel - [v12 05/20] clk: mediatek: Fix asymmetrical PLL enable and disable control

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date:   Mon, 5 Jul 2021 11:38:09 +0800
From:   Chun-Jie Chen <chun-jie.chen@...iatek.com>
To:     Matthias Brugger <matthias.bgg@...il.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Nicolas Boichat <drinkcat@...omium.org>,
        Rob Herring <robh+dt@...nel.org>
CC:     <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-mediatek@...ts.infradead.org>, <linux-clk@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <srv_heupstream@...iatek.com>,
        <Project_Global_Chrome_Upstream_Group@...iatek.com>,
        Weiyi Lu <weiyi.lu@...iatek.com>,
        Chun-Jie Chen <chun-jie.chen@...iatek.com>
Subject: [v12 05/20] clk: mediatek: Fix asymmetrical PLL enable and disable control

In fact, the en_mask is a combination of divider enable mask
and pll enable bit(bit0).
Before this patch, we enabled both divider mask and bit0 in prepare(),
but only cleared the bit0 in unprepare().
In the future, we hope en_mask will only be used as divider enable mask.
The enable register(CON0) will be set in 2 steps:
first is divider mask, and then bit0 during prepare(), and vice versa.
But considering backward compatibility, at this stage we allow en_mask
to be a combination or a pure divider enable mask.
And then we will make en_mask a pure divider enable mask in another
following patch series.

Reviewed-by: Ikjoon Jang <ikjn@...omium.org>
Signed-off-by: Weiyi Lu <weiyi.lu@...iatek.com>
Signed-off-by: Chun-Jie Chen <chun-jie.chen@...iatek.com>
---
 drivers/clk/mediatek/clk-pll.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/mediatek/clk-pll.c b/drivers/clk/mediatek/clk-pll.c
index f440f2cd0b69..11ed5d1d1c36 100644
--- a/drivers/clk/mediatek/clk-pll.c
+++ b/drivers/clk/mediatek/clk-pll.c
@@ -238,6 +238,7 @@ static int mtk_pll_prepare(struct clk_hw *hw)
 {
 	struct mtk_clk_pll *pll = to_mtk_clk_pll(hw);
 	u32 r;
+	u32 div_en_mask;
 
 	r = readl(pll->pwr_addr) | CON0_PWR_ON;
 	writel(r, pll->pwr_addr);
@@ -247,10 +248,15 @@ static int mtk_pll_prepare(struct clk_hw *hw)
 	writel(r, pll->pwr_addr);
 	udelay(1);
 
-	r = readl(pll->base_addr + REG_CON0);
-	r |= pll->data->en_mask;
+	r = readl(pll->base_addr + REG_CON0) | CON0_BASE_EN;
 	writel(r, pll->base_addr + REG_CON0);
 
+	div_en_mask = pll->data->en_mask & ~CON0_BASE_EN;
+	if (div_en_mask) {
+		r = readl(pll->base_addr + REG_CON0) | div_en_mask;
+		writel(r, pll->base_addr + REG_CON0);
+	}
+
 	__mtk_pll_tuner_enable(pll);
 
 	udelay(20);
@@ -268,6 +274,7 @@ static void mtk_pll_unprepare(struct clk_hw *hw)
 {
 	struct mtk_clk_pll *pll = to_mtk_clk_pll(hw);
 	u32 r;
+	u32 div_en_mask;
 
 	if (pll->data->flags & HAVE_RST_BAR) {
 		r = readl(pll->base_addr + REG_CON0);
@@ -277,8 +284,13 @@ static void mtk_pll_unprepare(struct clk_hw *hw)
 
 	__mtk_pll_tuner_disable(pll);
 
-	r = readl(pll->base_addr + REG_CON0);
-	r &= ~CON0_BASE_EN;
+	div_en_mask = pll->data->en_mask & ~CON0_BASE_EN;
+	if (div_en_mask) {
+		r = readl(pll->base_addr + REG_CON0) & ~div_en_mask;
+		writel(r, pll->base_addr + REG_CON0);
+	}
+
+	r = readl(pll->base_addr + REG_CON0) & ~CON0_BASE_EN;
 	writel(r, pll->base_addr + REG_CON0);
 
 	r = readl(pll->pwr_addr) | CON0_ISO_EN;
-- 
2.18.0