[PATCH AUTOSEL 4.19 28/50] pinctrl: tegra: Fix write barrier placement in pmx_writel

Sasha Levin
2019-09-24T16:49:53Z

From: Sowjanya Komatineni <skomatineni@nvidia.com>

[ Upstream commit c2cf351eba2ff6002ce8eb178452219d2521e38e ]

pmx_writel uses writel which inserts write barrier before the
register write.

This patch has fix to replace writel with writel_relaxed followed
by a readback and memory barrier to ensure write operation is
completed for successful pinctrl change.

Acked-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Link: https://lore.kernel.org/r/1565984527-5272-2-git-send-email-skomatineni@nvidia.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pinctrl/tegra/pinctrl-tegra.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/pinctrl/tegra/pinctrl-tegra.c b/drivers/pinctrl/tegra/pinctrl-tegra.c
index 1aba75897d147..26a3f1eb9c6bf 100644
--- a/drivers/pinctrl/tegra/pinctrl-tegra.c
+++ b/drivers/pinctrl/tegra/pinctrl-tegra.c
@@ -40,7 +40,9 @@ static inline u32 pmx_readl(struct tegra_pmx *pmx, u32 bank, u32 reg)

static inline void pmx_writel(struct tegra_pmx *pmx, u32 val, u32 bank, u32 reg)
{
- writel(val, pmx->regs[bank] + reg);
+ writel_relaxed(val, pmx->regs[bank] + reg);
+ /* make sure pinmux register write completed */
+ pmx_readl(pmx, bank, reg);
}

static int tegra_pinctrl_get_groups_count(struct pinctrl_dev *pctldev)
--
2.20.1