Re: [PATCH 12/37] clk: renesas: rzg2l: reduce the critical area
From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: 2023-09-14 13:12:29
Also in:
linux-clk, linux-devicetree, linux-gpio, linux-mmc, linux-renesas-soc, linux-serial, lkml
Hi Claudiu, On Tue, Sep 12, 2023 at 6:52 AM Claudiu [off-list ref] wrote:
From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com> spinlock in rzg2l_mod_clock_endisable() is intended to protect the accesses to hardware register. There is no need to protect the instructions that set temporary variable which will be then written to register. Thus limit the spinlock only to the hardware register access. Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Thanks for your patch!
quoted hunk ↗ jump to hunk
--- a/drivers/clk/renesas/rzg2l-cpg.c +++ b/drivers/clk/renesas/rzg2l-cpg.c@@ -912,13 +912,13 @@ static int rzg2l_mod_clock_endisable(struct clk_hw *hw, bool enable) dev_dbg(dev, "CLK_ON %u/%pC %s\n", CLK_ON_R(reg), hw->clk, enable ? "ON" : "OFF"); - spin_lock_irqsave(&priv->rmw_lock, flags); value = bitmask << 16; if (enable) value |= bitmask; - writel(value, priv->base + CLK_ON_R(reg)); + spin_lock_irqsave(&priv->rmw_lock, flags); + writel(value, priv->base + CLK_ON_R(reg)); spin_unlock_irqrestore(&priv->rmw_lock, flags);
After this, it becomes obvious there is nothing to protect at all,
so the locking can just be removed from this function?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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