[PATCH] soc: qcom: smem: fix 32-bit overflow in DDR frequency calculation

[PATCH] soc: qcom: smem: fix 32-bit overflow in DDR frequency calculation

[Gopikrishna Garmidi]

The DDR frequency in SMEM is reported in kHz and converted to Hz by
multiplying it by 1000. Since the SMEM frequency value is a u32, using
an unsuffixed integer constant causes the multiplication to be performed
with 32-bit arithmetic.

This overflows for DDR frequencies above 4294967 kHz, resulting in an
incorrect frequency being reported through the SMEM DRAM interface.

Use an unsigned long constant for the multiplication so the calculation
is performed with 64-bit arithmetic on the supported Qualcomm platforms.
Apply the fix consistently to the v3, v3.1, v4, v5, and v7 SMEM parsers.

Fixes: 1d234eeafc56 ("soc: qcom: smem: Expose DDR data from SMEM")
Signed-off-by: Gopikrishna Garmidi <gopikrishna.garmidi@oss.qualcomm.com>
---
 drivers/soc/qcom/smem_dramc.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/soc/qcom/smem_dramc.c b/drivers/soc/qcom/smem_dramc.c
index 63ebe7f6db59..9612230a03be 100644
--- a/drivers/soc/qcom/smem_dramc.c
+++ b/drivers/soc/qcom/smem_dramc.c
@@ -219,7 +219,7 @@ static void smem_dram_parse_v3_data(struct smem_dram *dram, void *data)
 
 		if (freq_entry->freq_khz && freq_entry->enabled) {
 			u32 freq_khz = le32_to_cpu(freq_entry->freq_khz);
-			dram->frequencies[dram->num_frequencies++] = 1000 * freq_khz;
+			dram->frequencies[dram->num_frequencies++] = 1000UL * freq_khz;
 		}
 	}
 }
@@ -232,7 +232,7 @@ static void smem_dram_parse_v3_14freqs_data(struct smem_dram *dram, void *data)
 		struct ddr_freq_table *freq_entry = &details->ddr_freq_tbl.ddr_freq[i];
 
 		if (freq_entry->freq_khz && freq_entry->enabled)
-			dram->frequencies[dram->num_frequencies++] = 1000 * freq_entry->freq_khz;
+			dram->frequencies[dram->num_frequencies++] = 1000UL * freq_entry->freq_khz;
 	}
 }
 
@@ -248,7 +248,7 @@ static void smem_dram_parse_v4_data(struct smem_dram *dram, void *data)
 
 		if (freq_entry->freq_khz && freq_entry->enabled) {
 			u32 freq_khz = le32_to_cpu(freq_entry->freq_khz);
-			dram->frequencies[dram->num_frequencies++] = 1000 * freq_khz;
+			dram->frequencies[dram->num_frequencies++] = 1000UL * freq_khz;
 		}
 	}
 }
@@ -265,7 +265,7 @@ static void smem_dram_parse_v5_data(struct smem_dram *dram, void *data)
 
 		if (freq_entry->freq_khz && freq_entry->enabled) {
 			u32 freq_khz = le32_to_cpu(freq_entry->freq_khz);
-			dram->frequencies[dram->num_frequencies++] = 1000 * freq_khz;
+			dram->frequencies[dram->num_frequencies++] = 1000UL * freq_khz;
 		}
 	}
 }
@@ -282,7 +282,7 @@ static void smem_dram_parse_v7_data(struct smem_dram *dram, void *data)
 
 		if (freq_entry->freq_khz && freq_entry->enabled) {
 			u32 freq_khz = le32_to_cpu(freq_entry->freq_khz);
-			dram->frequencies[dram->num_frequencies++] = 1000 * freq_khz;
+			dram->frequencies[dram->num_frequencies++] = 1000UL * freq_khz;
 		}
 	}
 }

---
base-commit: f82a5da2f04960df9fb57489992d03dd5e64ec6f
change-id: 20260826-glymur_dramc-55f6a0508ae0

Best regards,
--  
Gopikrishna Garmidi <gopikrishna.garmidi@oss.qualcomm.com>

Re: [PATCH] soc: qcom: smem: fix 32-bit overflow in DDR frequency calculation

[Konrad Dybcio]

On 8/27/26 10:13 AM, Gopikrishna Garmidi wrote:
> The DDR frequency in SMEM is reported in kHz and converted to Hz by
> multiplying it by 1000. Since the SMEM frequency value is a u32, using
> an unsuffixed integer constant causes the multiplication to be performed
> with 32-bit arithmetic.
> 
> This overflows for DDR frequencies above 4294967 kHz, resulting in an
> incorrect frequency being reported through the SMEM DRAM interface.
> 
> Use an unsigned long constant for the multiplication so the calculation
> is performed with 64-bit arithmetic on the supported Qualcomm platforms.
> Apply the fix consistently to the v3, v3.1, v4, v5, and v7 SMEM parsers.
> 
> Fixes: 1d234eeafc56 ("soc: qcom: smem: Expose DDR data from SMEM")
> Signed-off-by: Gopikrishna Garmidi <gopikrishna.garmidi@oss.qualcomm.com>
> ---

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Konrad

Re: [PATCH] soc: qcom: smem: fix 32-bit overflow in DDR frequency calculation

[Bjorn Andersson]

On Thu, 27 Aug 2026 01:13:17 -0700, Gopikrishna Garmidi wrote:
> The DDR frequency in SMEM is reported in kHz and converted to Hz by
> multiplying it by 1000. Since the SMEM frequency value is a u32, using
> an unsuffixed integer constant causes the multiplication to be performed
> with 32-bit arithmetic.
> 
> This overflows for DDR frequencies above 4294967 kHz, resulting in an
> incorrect frequency being reported through the SMEM DRAM interface.
> 
> [...]

Applied, thanks!

[1/1] soc: qcom: smem: fix 32-bit overflow in DDR frequency calculation
      commit: 7bb5f186784074f2a91d83e191e305238be47103

Best regards,
-- 
Bjorn Andersson <andersson@kernel.org>