Commit 4119bd55 authored Dec 15, 2020 by Tomi Valkeinen

drm/omap: pll: fix iteration loop check

If the PLL calc function is given bad parameters, n_start/m_start may be
higher than n_stop/m_stop, which leads to the loops iterating through
the whole u32 number space.

Fix this by failing early on such cases.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201215104657.802264-59-tomi.valkeinen@ti.com

parent 0073b8cd

drivers/gpu/drm/omapdrm/dss/pll.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -222,6 +222,9 @@ bool dss_pll_calc_a(const struct dss_pll *pll, unsigned long clkin,
		n_stop = min((unsigned)(clkin / fint_hw_min), hw->n_max);
		n_inc = 1;

		if (n_start > n_stop)
		return false;

		if (hw->errata_i886) {
		swap(n_start, n_stop);
		n_inc = -1;
		@@ -239,6 +242,9 @@ bool dss_pll_calc_a(const struct dss_pll *pll, unsigned long clkin,
		hw->m_max);
		m_inc = 1;

		if (m_start > m_stop)
		continue;

		if (hw->errata_i886) {
		swap(m_start, m_stop);
		m_inc = -1;