Commit fd75f371 authored by Christian Bruel's avatar Christian Bruel Committed by Vinod Koul
Browse files

phy: stm32: Fix constant-value overflow assertion 



Rework the workaround as the lookup tables always fits into the bitfield,
and the default values are defined by the hardware and cannot be 0:

Guard against false positive with a WARN_ON check to make the compiler
happy: The offset range is pre-checked against the sorted imp_lookup_table
values and overflow should not happen and would be caught by a warning and
return in error.

Also guard against a true positive found during the max_vswing lookup, as a
max vswing value can be 802000 or 803000 microvolt depending on the current
impedance. Therefore set the default impedence index.

Fixes: 2de679ec ("phy: stm32: work around constant-value overflow assertion")
Signed-off-by: default avatarChristian Bruel <christian.bruel@foss.st.com>
Link: https://lore.kernel.org/r/20250210103515.2598377-1-christian.bruel@foss.st.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 3126ea9b

drivers/phy/st/phy-stm32-combophy.c

+18 −20
Original line number Diff line number Diff line
@@ -111,6 +111,7 @@ static const struct clk_impedance imp_lookup[] = { 
	{ 4204000, { 511000, 609000, 706000, 802000 } },

	{ 3999000, { 571000, 648000, 726000, 803000 } }

};

#define DEFAULT_IMP_INDEX 3 /* Default impedance is 50 Ohm */



static int stm32_impedance_tune(struct stm32_combophy *combophy)

{
@@ -119,10 +120,9 @@ static int stm32_impedance_tune(struct stm32_combophy *combophy) 
	u8 imp_of, vswing_of;

	u32 max_imp = imp_lookup[0].microohm;

	u32 min_imp = imp_lookup[imp_size - 1].microohm;

	u32 max_vswing = imp_lookup[imp_size - 1].vswing[vswing_size - 1];

	u32 max_vswing;

	u32 min_vswing = imp_lookup[0].vswing[0];

	u32 val;

	u32 regval;



	if (!of_property_read_u32(combophy->dev->of_node, "st,output-micro-ohms", &val)) {

		if (val < min_imp || val > max_imp) {
@@ -130,45 +130,43 @@ static int stm32_impedance_tune(struct stm32_combophy *combophy) 
			return -EINVAL;

		}



		regval = 0;

		for (imp_of = 0; imp_of < ARRAY_SIZE(imp_lookup); imp_of++) {

			if (imp_lookup[imp_of].microohm <= val) {

				regval = FIELD_PREP(STM32MP25_PCIEPRG_IMPCTRL_OHM, imp_of);

		for (imp_of = 0; imp_of < ARRAY_SIZE(imp_lookup); imp_of++)

			if (imp_lookup[imp_of].microohm <= val)

				break;

			}

		}



		if (WARN_ON(imp_of == ARRAY_SIZE(imp_lookup)))

			return -EINVAL;



		dev_dbg(combophy->dev, "Set %u micro-ohms output impedance\n",

			imp_lookup[imp_of].microohm);



		regmap_update_bits(combophy->regmap, SYSCFG_PCIEPRGCR,

				   STM32MP25_PCIEPRG_IMPCTRL_OHM,

				   regval);

	} else {

		regmap_read(combophy->regmap, SYSCFG_PCIEPRGCR, &val);

		imp_of = FIELD_GET(STM32MP25_PCIEPRG_IMPCTRL_OHM, val);

	}

				   FIELD_PREP(STM32MP25_PCIEPRG_IMPCTRL_OHM, imp_of));

	} else

		imp_of = DEFAULT_IMP_INDEX;



	if (!of_property_read_u32(combophy->dev->of_node, "st,output-vswing-microvolt", &val)) {

		max_vswing = imp_lookup[imp_of].vswing[vswing_size - 1];



		if (val < min_vswing || val > max_vswing) {

			dev_err(combophy->dev, "Invalid value %u for output vswing\n", val);

			return -EINVAL;

		}



		regval = 0;

		for (vswing_of = 0; vswing_of < ARRAY_SIZE(imp_lookup[imp_of].vswing); vswing_of++) {

			if (imp_lookup[imp_of].vswing[vswing_of] >= val) {

				regval = FIELD_PREP(STM32MP25_PCIEPRG_IMPCTRL_VSWING, vswing_of);

		for (vswing_of = 0; vswing_of < ARRAY_SIZE(imp_lookup[imp_of].vswing); vswing_of++)

			if (imp_lookup[imp_of].vswing[vswing_of] >= val)

				break;

			}

		}



		if (WARN_ON(vswing_of == ARRAY_SIZE(imp_lookup[imp_of].vswing)))

			return -EINVAL;



		dev_dbg(combophy->dev, "Set %u microvolt swing\n",

			 imp_lookup[imp_of].vswing[vswing_of]);



		regmap_update_bits(combophy->regmap, SYSCFG_PCIEPRGCR,

				   STM32MP25_PCIEPRG_IMPCTRL_VSWING,

				   regval);

				   FIELD_PREP(STM32MP25_PCIEPRG_IMPCTRL_VSWING, vswing_of));

	}



	return 0;