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phy: stm32: Fix constant-value overflow assertion

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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: 2de679ecd7 ("phy: stm32: work around constant-value overflow assertion")
Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
Link: https://lore.kernel.org/r/20250210103515.2598377-1-christian.bruel@foss.st.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Christian Bruel 2025-02-10 11:35:15 +01:00 • committed by Vinod Koul
parent 3126ea9be6
commit fd75f371f3
1 changed files with 18 additions and 20 deletions
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38
drivers/phy/st/phy-stm32-combophy.c
View file

@ -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;