From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 010C3221F24; Tue, 9 Dec 2025 20:17:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765311448; cv=none; b=eLjYsxwIf2gOm24HAkKOB78yWMn311SzHy1WlCJYUDiEUQinztEfBy1XiBPJcdWThGTNLYLgcwRX+plW3sr6WKoNnSKyS1Kw0fXLHpKvp/WVMokaWP5snaUhOG3icBNmaYaIrQUTYpmJ1VV5+FRp+XtzQmkGLOt0qIzxM50D994= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765311448; c=relaxed/simple; bh=WaUkBQ4r806vyiBGKBACPoJXtG1aq44WJUp8ANciYac=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mhoLm4dGpVKVBbUNUH51LynUhyt2otDes1xdC6aINt9yoglXfd30EUuHCwUXDNKbdhW7dYiES/MvXu1p7N5fnUUfddfU1P0OxunMkur/AezT+DygI4kz7GBJgg2XnF4C9M2rqw8xGb8mpP0kcmXFaPBa+uY7uoIcwev/97LhiEE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Qrt9O9Gq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Qrt9O9Gq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 31427C4CEF5; Tue, 9 Dec 2025 20:17:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765311447; bh=WaUkBQ4r806vyiBGKBACPoJXtG1aq44WJUp8ANciYac=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Qrt9O9GqjfTKzm00Hh0OsM3usbi57/q7ndBFnw8Zo0q4lsP4he+NLmeT0sj5EJ1ox FTTtMlYI4tzQsAYHFsJczTkw2iUf6/WUqtD73kQQZiaifkYcalc3LLAKnsIse2P9aG qfK4GWhyg2bRuUxrfxBrnbAATZ5l2YXuJxioPw+dx7ft/7e4KwA65LSAuwEWikuMRt SuLaJWWqZEStsgWiJp+g9Zuf40FW8MX6Pf2w2Ii3/lkGJMPovJOMfCdsX5pGUUGa35 CxHFypwCxjnYQk+07iVbrBaACB77MOPhPSFgvlULD0/TpINOcPGxilmlVK+lZ+vALu kEe1KmBREwvMQ== Date: Tue, 9 Dec 2025 14:17:25 -0600 From: Rob Herring To: Vijayanand Jitta Cc: robin.murphy@arm.com, will@kernel.org, joro@8bytes.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, charan.kalla@oss.qualcomm.com, prakash.gupta@oss.qualcomm.com, vikash.garodia@oss.qualcomm.com, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org Subject: Re: [PATCH v2 3/3] of: Respect #{iommu,msi}-cells in maps Message-ID: <20251209201725.GB1015230-robh@kernel.org> References: <20251204095530.8627-1-vijayanand.jitta@oss.qualcomm.com> <20251204095530.8627-4-vijayanand.jitta@oss.qualcomm.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251204095530.8627-4-vijayanand.jitta@oss.qualcomm.com> On Thu, Dec 04, 2025 at 03:25:30PM +0530, Vijayanand Jitta wrote: > 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: Vijayanand Jitta > --- > drivers/iommu/of_iommu.c | 3 +- > drivers/of/base.c | 107 ++++++++++++++++++++++++++++++--------- > include/linux/of.h | 17 ++++--- > 3 files changed, 94 insertions(+), 33 deletions(-) > > diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c > index eac62bc441c5..48759cf1d900 100644 > --- a/drivers/iommu/of_iommu.c > +++ b/drivers/iommu/of_iommu.c > @@ -45,10 +45,11 @@ static int of_iommu_configure_dev_id(struct device_node *master_np, > struct device *dev, > const u32 *id) > { > - struct of_phandle_args iommu_spec = { .args_count = 1 }; > + struct of_phandle_args iommu_spec = {}; > struct of_map_id_arg arg = { > .target = &iommu_spec.np, > .id_out = iommu_spec.args, > + .map_cells = &iommu_spec.args_count, > }; > int err; > > diff --git a/drivers/of/base.c b/drivers/of/base.c > index b8f78a9e6a09..68a7d6ddba66 100644 > --- a/drivers/of/base.c > +++ b/drivers/of/base.c > @@ -2045,11 +2045,30 @@ int of_find_last_cache_level(unsigned int cpu) > return cache_level; > } > > +/* > + * Some DTs have an iommu-map targeting a 2-cell IOMMU node while > + * specifying only 1 cell. Fortunately they all consist of length == 1 > + * entries with the same target, so check for that pattern. Can you show what a bad entry looks like here. > + */ > +static bool of_check_bad_map(const __be32 *map, int len) > +{ > + __be32 phandle = map[1]; > + > + if (len % 4) > + return false; > + for (int i = 0; i < len; i += 4) { > + if (map[i + 1] != phandle || map[i + 3] != cpu_to_be32(1)) Why does the IOMMU arg cell have to be 1? The description said 'same target', but it is just all have an IOMMU cell value of 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: contains the optional params, @target which is a pointer > * to the target device node and id_out which is a pointer > @@ -2065,18 +2084,19 @@ 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_map_id_arg *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_map_id_arg *arg) > { > u32 map_mask, masked_id; > - int map_len; > + int map_bytes, map_len, offset = 0; > + bool bad_map = false; > const __be32 *map = NULL; > > if (!np || !map_name || !arg || (!arg->target && !arg->id_out)) > return -EINVAL; > > - map = of_get_property(np, map_name, &map_len); > + map = of_get_property(np, map_name, &map_bytes); > if (!map) { > if (arg->target) > return -ENODEV; > @@ -2085,11 +2105,9 @@ int of_map_id(const struct device_node *np, u32 id, > return 0; > } > > - 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 = map_bytes / sizeof(*map); > > /* The default is to select all bits. */ > map_mask = 0xffffffff; > @@ -2102,27 +2120,62 @@ int of_map_id(const struct device_node *np, u32 id, > of_property_read_u32(np, map_mask_name, &map_mask); > > masked_id = map_mask & id; > - for ( ; map_len > 0; map_len -= 4 * sizeof(*map), map += 4) { > + while (offset < map_len) { > struct device_node *phandle_node; > - u32 id_base = be32_to_cpup(map + 0); > - u32 phandle = be32_to_cpup(map + 1); > - u32 out_base = be32_to_cpup(map + 2); > - u32 id_len = be32_to_cpup(map + 3); > + u32 id_base, phandle, cells, id_len, id_off; > + const __be32 *out_base; > + > + if (map_len - offset < 2) > + goto err_map_len; > > + id_base = be32_to_cpup(map + offset); > 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, > + 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; > } > > - if (masked_id < id_base || masked_id >= id_base + id_len) > - continue; > - > + phandle = be32_to_cpup(map + offset + 1); > phandle_node = of_find_node_by_phandle(phandle); > if (!phandle_node) > return -ENODEV; > > + 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 == 0 && cells == 2) { > + bad_map = 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 = 1; > + } > + } > + > + out_base = map + offset + 2; > + offset += 3 + cells; > + > + id_len = 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 output specifier\n", > + np, map_name, id_len, cells); > + return -EINVAL; > + } > + id_off = masked_id - id_base; > + if (masked_id < id_base || id_off >= id_len) > + continue; > + > if (arg->target) { > if (*arg->target) > of_node_put(phandle_node); > @@ -2133,12 +2186,14 @@ int of_map_id(const struct device_node *np, u32 id, > continue; > } > > - if (arg->id_out) > - *arg->id_out = masked_id - id_base + out_base; > + for (int i = 0; arg->id_out && i < cells; i++) > + arg->id_out[i] = id_off + be32_to_cpu(out_base[i]); > > + if (arg->map_cells) > + *arg->map_cells = cells; > pr_debug("%pOF: %s, using mask %08x, id-base: %08x, out-base: %08x, length: %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; > } > > @@ -2149,5 +2204,9 @@ int of_map_id(const struct device_node *np, u32 id, > if (arg->id_out) > *arg->id_out = 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 21bdce2b37ca..1981509c7918 100644 > --- a/include/linux/of.h > +++ b/include/linux/of.h > @@ -29,6 +29,7 @@ struct device_node; > struct of_map_id_arg { > struct device_node **target; > u32 *id_out; > + u32 *map_cells; > }; > > struct property { > @@ -462,9 +463,9 @@ const char *of_prop_next_string(const struct property *prop, const char *cur); > > bool of_console_check(const struct device_node *dn, char *name, int index); > > -int of_map_id(const struct device_node *np, u32 id, > - const char *map_name, const char *map_mask_name, > - struct of_map_id_arg *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_map_id_arg *arg); > > phys_addr_t of_dma_get_max_cpu_address(struct device_node *np); > > @@ -911,9 +912,9 @@ static inline void of_property_clear_flag(struct property *p, unsigned long flag > { > } > > -static inline int of_map_id(const struct device_node *np, u32 id, > - const char *map_name, const char *map_mask_name, > - struct of_map_id_arg *arg) > +static inline 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_map_id_arg *arg); > { > return -EINVAL; > } > @@ -1444,7 +1445,7 @@ static inline int of_property_read_s32(const struct device_node *np, > static inline int of_map_iommu_id(const struct device_node *np, u32 id, > struct of_map_id_arg *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", arg); > } > > static inline int of_map_msi_id(const struct device_node *np, u32 id, > @@ -1455,7 +1456,7 @@ static inline int of_map_msi_id(const struct device_node *np, u32 id, > .id_out = id_out, > }; > > - return of_map_id(np, id, "msi-map", "msi-map-mask", &arg); > + return of_map_id(np, id, "msi-map", "#msi-cells", "msi-map-mask", &arg); There are cases of no #msi-cells and we default to 0 cells in that case. Do you maintain that? Rob