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Tue, 10 Feb 2026 02:12:42 -0800 (PST) Received: from hu-vjitta-hyd.qualcomm.com ([202.46.23.25]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-82441884b75sm14380940b3a.39.2026.02.10.02.12.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Feb 2026 02:12:41 -0800 (PST) From: Vijayanand Jitta To: robin.murphy@arm.com, will@kernel.org, joro@8bytes.org, robh@kernel.org, dmitry.baryshkov@oss.qualcomm.com, konrad.dybcio@oss.qualcomm.com, bjorn.andersson@oss.qualcomm.com, bod@kernel.org, conor+dt@kernel.org, krzk+dt@kernel.org, prakash.gupta@oss.qualcomm.com, vikash.garodia@oss.qualcomm.com Cc: iommu@lists.linux.dev, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Charan Teja Kalla , Vijayanand Jitta Subject: [PATCH v7 3/3] of: Respect #{iommu,msi}-cells in maps Date: Tue, 10 Feb 2026 15:41:57 +0530 Message-Id: <20260210101157.2145113-4-vijayanand.jitta@oss.qualcomm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260210101157.2145113-1-vijayanand.jitta@oss.qualcomm.com> References: <20260210101157.2145113-1-vijayanand.jitta@oss.qualcomm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Proofpoint-ORIG-GUID: gOV86Qb59lhRlkdb0-BReuHzhR6B3mwv X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMjEwMDA4NCBTYWx0ZWRfX0IyecznP1FmI HPdLRThzAl2Xzo4hgD1UtKAcoc73jX4JWUoX1WUbasNz1Spp2sG6ZLxwqaaRmu671y5t6S8kGiL Qgk/kPs2dh76p1vA4pOhOIg5RCM5Jf/pz2z5nLCsoHV8CwKKadjppBpFwHaxeh1XlOBgEHlV09c dLNPzVRfxzlpPx7xx6o9TEMDgr8iXBcUL0Jf0G3ajusJzpha5ZDhTwLb9D+5dMcXpWF7dSP8cKa JFqbID1pEmpnvi2SJL4Vp/WkRzMpCz809yW3FKWsIBxvpG61+tz1HLAjWr4prXpsOKldIapq4Wh 8O8LCVZ3fD5NETzarRvxsuncVrEF9FZFnpdkamcKUJ7LJKZST3nNqwecneYOVPx+DSxcz3UBz1V vuMQM6PuaBGA3tiKDNnCWdqqkOzjt+t3WvXODW2yxmUyREbpTDQsJSjdQ1rFa+taF+ijYirdJq2 52JTMs3RC+PSaV2srmw== X-Authority-Analysis: v=2.4 cv=F6Rat6hN c=1 sm=1 tr=0 ts=698b049b cx=c_pps a=WW5sKcV1LcKqjgzy2JUPuA==:117 a=ZePRamnt/+rB5gQjfz0u9A==:17 a=HzLeVaNsDn8A:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=Mpw57Om8IfrbqaoTuvik:22 a=GgsMoib0sEa3-_RKJdDe:22 a=7CQSdrXTAAAA:8 a=EUspDBNiAAAA:8 a=wJGdY9mNwEi-N7fqGJcA:9 a=OpyuDcXvxspvyRM73sMx:22 a=a-qgeE7W1pNrGK8U0ZQC:22 X-Proofpoint-GUID: gOV86Qb59lhRlkdb0-BReuHzhR6B3mwv X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-02-09_01,2026-02-09_04,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 priorityscore=1501 phishscore=0 suspectscore=0 malwarescore=0 bulkscore=0 impostorscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2601150000 definitions=main-2602100084 Content-Type: text/plain; charset="utf-8" From: Robin Murphy So far our parsing of {iommu,msi}-map properites has always blindly asusmed that the output specifiers will always have exactly 1 cell. This typically does happen to be the case, but is not actually enforced (and the PCI msi-map binding even explicitly states support for 0 or 1 cells) - as a result we've now ended up with dodgy DTs out in the field which depend on this behaviour to map a 1-cell specifier for a 2-cell provider, despite that being bogus per the bindings themselves. Since there is some potential use in being able to map at least single input IDs to multi-cell output specifiers (and properly support 0-cell outputs as well), add support for properly parsing and using the target nodes' #cells values, albeit with the unfortunate complication of still having to work around expectations of the old behaviour too. Since there are multi-cell output specifiers, the callers of of_map_id() may need to get the exact cell output value for further processing. Added support for that part --charan Signed-off-by: Robin Murphy Signed-off-by: Charan Teja Kalla Signed-off-by: Vijayanand Jitta --- drivers/iommu/of_iommu.c | 2 +- drivers/of/base.c | 117 +++++++++++++++++++++++++++++++-------- include/linux/of.h | 16 +++--- 3 files changed, 102 insertions(+), 33 deletions(-) diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c index d255d0f58e8c..a18bb60f6f3d 100644 --- a/drivers/iommu/of_iommu.c +++ b/drivers/iommu/of_iommu.c @@ -45,7 +45,7 @@ static int of_iommu_configure_dev_id(struct device_node *= master_np, struct device *dev, const u32 *id) { - struct of_phandle_args iommu_spec =3D { .args_count =3D 1 }; + struct of_phandle_args iommu_spec =3D {}; int err; =20 err =3D of_map_iommu_id(master_np, *id, &iommu_spec); diff --git a/drivers/of/base.c b/drivers/of/base.c index 6c3628255908..596bcf993dcb 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -2096,11 +2096,38 @@ int of_find_last_cache_level(unsigned int cpu) return cache_level; } =20 +/* + * Some DTs have an iommu-map targeting a 2-cell IOMMU node while + * specifying only 1 cell. Fortunately they all consist of value '1' + * as the 2nd cell entry with the same target, so check for that pattern. + * + * Example: + * IOMMU node: + * #iommu-cells =3D <2>; + * + * Device node: + * iommu-map =3D <0x0000 &smmu 0x0000 0x1>, + * <0x0100 &smmu 0x0100 0x1>; + */ +static bool of_check_bad_map(const __be32 *map, int len) +{ + __be32 phandle =3D map[1]; + + if (len % 4) + return false; + for (int i =3D 0; i < len; i +=3D 4) { + if (map[i + 1] !=3D phandle || map[i + 3] !=3D cpu_to_be32(1)) + return false; + } + return true; +} + /** * of_map_id - Translate an ID through a downstream mapping. * @np: root complex device node. * @id: device ID to map. * @map_name: property name of the map to use. + * @cells_name: property name of target specifier cells. * @map_mask_name: optional property name of the mask to use. * @arg: of_phandle_args structure, * which includes: @@ -2118,18 +2145,19 @@ int of_find_last_cache_level(unsigned int cpu) * * Return: 0 on success or a standard error code on failure. */ -int of_map_id(const struct device_node *np, u32 id, - const char *map_name, const char *map_mask_name, - struct of_phandle_args *arg) +int of_map_id(const struct device_node *np, u32 id, const char *map_name, + const char *cells_name, const char *map_mask_name, + struct of_phandle_args *arg) { u32 map_mask, masked_id; - int map_len; + int map_bytes, map_len, offset =3D 0; + bool bad_map =3D false; const __be32 *map =3D NULL; =20 if (!np || !map_name || !arg) return -EINVAL; =20 - map =3D of_get_property(np, map_name, &map_len); + map =3D of_get_property(np, map_name, &map_bytes); if (!map) { if (arg->np) return -ENODEV; @@ -2138,11 +2166,9 @@ int of_map_id(const struct device_node *np, u32 id, return 0; } =20 - if (!map_len || map_len % (4 * sizeof(*map))) { - pr_err("%pOF: Error: Bad %s length: %d\n", np, - map_name, map_len); - return -EINVAL; - } + if (map_bytes % sizeof(*map)) + goto err_map_len; + map_len =3D map_bytes / sizeof(*map); =20 /* The default is to select all bits. */ map_mask =3D 0xffffffff; @@ -2155,27 +2181,63 @@ int of_map_id(const struct device_node *np, u32 id, of_property_read_u32(np, map_mask_name, &map_mask); =20 masked_id =3D map_mask & id; - for ( ; map_len > 0; map_len -=3D 4 * sizeof(*map), map +=3D 4) { + + while (offset < map_len) { struct device_node *phandle_node; - u32 id_base =3D be32_to_cpup(map + 0); - u32 phandle =3D be32_to_cpup(map + 1); - u32 out_base =3D be32_to_cpup(map + 2); - u32 id_len =3D be32_to_cpup(map + 3); + u32 id_base, phandle, id_len, id_off, cells =3D 0; + const __be32 *out_base; + + if (map_len - offset < 2) + goto err_map_len; + + id_base =3D be32_to_cpup(map + offset); =20 if (id_base & ~map_mask) { - pr_err("%pOF: Invalid %s translation - %s-mask (0x%x) ignores id-base (= 0x%x)\n", - np, map_name, map_name, - map_mask, id_base); + pr_err("%pOF: Invalid %s translation - %s (0x%x) ignores id-base (0x%x)= \n", + np, map_name, map_mask_name, map_mask, id_base); return -EFAULT; } =20 - if (masked_id < id_base || masked_id >=3D id_base + id_len) - continue; - + phandle =3D be32_to_cpup(map + offset + 1); phandle_node =3D of_find_node_by_phandle(phandle); if (!phandle_node) return -ENODEV; =20 + if (!bad_map && of_property_read_u32(phandle_node, cells_name, &cells)) { + pr_err("%pOF: missing %s property\n", phandle_node, cells_name); + return -EINVAL; + } + + if (map_len - offset < 3 + cells) + goto err_map_len; + + if (offset =3D=3D 0 && cells =3D=3D 2) { + bad_map =3D of_check_bad_map(map, map_len); + if (bad_map) { + pr_warn_once("%pOF: %s mismatches target %s, assuming extra cell of 0\= n", + np, map_name, cells_name); + cells =3D 1; + } + } + + out_base =3D map + offset + 2; + offset +=3D 3 + cells; + + id_len =3D be32_to_cpup(map + offset - 1); + if (id_len > 1 && cells > 1) { + /* + * With 1 output cell we reasonably assume its value + * has a linear relationship to the input; with more, + * we'd need help from the provider to know what to do. + */ + pr_err("%pOF: Unsupported %s - cannot handle %d-ID range with %d-cell o= utput specifier\n", + np, map_name, id_len, cells); + return -EINVAL; + } + id_off =3D masked_id - id_base; + if (masked_id < id_base || id_off >=3D id_len) + continue; + if (arg->np) of_node_put(phandle_node); else @@ -2184,11 +2246,14 @@ int of_map_id(const struct device_node *np, u32 id, if (arg->np !=3D phandle_node) continue; =20 - arg->args[0] =3D masked_id - id_base + out_base; + for (int i =3D 0; i < cells; i++) + arg->args[i] =3D (id_off + be32_to_cpu(out_base[i])); + + arg->args_count =3D cells; =20 pr_debug("%pOF: %s, using mask %08x, id-base: %08x, out-base: %08x, leng= th: %08x, id: %08x -> %08x\n", - np, map_name, map_mask, id_base, out_base, - id_len, id, masked_id - id_base + out_base); + np, map_name, map_mask, id_base, be32_to_cpup(out_base), + id_len, id, id_off + be32_to_cpup(out_base)); return 0; } =20 @@ -2198,5 +2263,9 @@ int of_map_id(const struct device_node *np, u32 id, /* Bypasses translation */ arg->args[0] =3D id; return 0; + +err_map_len: + pr_err("%pOF: Error: Bad %s length: %d\n", np, map_name, map_bytes); + return -EINVAL; } EXPORT_SYMBOL_GPL(of_map_id); diff --git a/include/linux/of.h b/include/linux/of.h index 9d72d76f909d..5b5b5dc2d3f3 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -461,9 +461,9 @@ const char *of_prop_next_string(const struct property *= prop, const char *cur); =20 bool of_console_check(const struct device_node *dn, char *name, int index); =20 -int of_map_id(const struct device_node *np, u32 id, - const char *map_name, const char *map_mask_name, - struct of_phandle_args *arg); +int of_map_id(const struct device_node *np, u32 id, const char *map_name, + const char *cells_name, const char *map_mask_name, + struct of_phandle_args *arg); =20 phys_addr_t of_dma_get_max_cpu_address(struct device_node *np); =20 @@ -927,9 +927,9 @@ static inline void of_property_clear_flag(struct proper= ty *p, unsigned long flag { } =20 -static inline int of_map_id(const struct device_node *np, u32 id, - const char *map_name, const char *map_mask_name, - struct of_phandle_args *arg) +static inline int of_map_id(const struct device_node *np, u32 id, const ch= ar *map_name, + const char *cells_name, const char *map_mask_name, + struct of_phandle_args *arg) { return -EINVAL; } @@ -1460,7 +1460,7 @@ static inline int of_property_read_s32(const struct d= evice_node *np, static inline int of_map_iommu_id(const struct device_node *np, u32 id, struct of_phandle_args *arg) { - return of_map_id(np, id, "iommu-map", "iommu-map-mask", arg); + return of_map_id(np, id, "iommu-map", "#iommu-cells", "iommu-map-mask", a= rg); } =20 static inline int of_map_msi_id(const struct device_node *np, u32 id, @@ -1469,7 +1469,7 @@ static inline int of_map_msi_id(const struct device_n= ode *np, u32 id, struct of_phandle_args msi_spec =3D { .np =3D *target, .args_count =3D 1 = }; int ret; =20 - ret =3D of_map_id(np, id, "msi-map", "msi-map-mask", &msi_spec); + ret =3D of_map_id(np, id, "msi-map", "#msi-cells", "msi-map-mask", &msi_s= pec); if (!ret) { *target =3D msi_spec.np; *id_out =3D msi_spec.args[0]; --=20 2.34.1