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 96C2F16F271; Tue, 4 Mar 2025 19:15:27 +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=1741115727; cv=none; b=BCyhxqGR1YYKBkNYicE4ctylmoZvep1kEQkkq4FZfeKVUpq1fmbj4vDmhOctKwwRhU4Rw38avgKQ4uv40IKxjB2Myjwki45am+NMqw+q9X27f54B5azhbMEDZGSacU0chYkHLkJ/XoyM/c1VZ/QIj4iGi/48FyTTgfsMY64QOLk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741115727; c=relaxed/simple; bh=NJ3TQZFfV3q3elNa2NxItYJQTy6CMZkFNGwhlIZAytw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lp47s9OdcQqvRVmDROWNsEl17OZudnzQzdZR4kZu6rY4fObYRwi/ZfwrEJotB4mG2+7L6ar/U5O4VT1INGQ+Ocr2h61IJi5ATVxHHkgtqD2GgCcGrByQDK5A7eBo6iJYwqQhVrv1MVImGqmApuaiUnLR5xw/oMVpfrHoN0++aZ8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oTq6rl92; 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="oTq6rl92" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5E51EC4CEE5; Tue, 4 Mar 2025 19:15:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741115727; bh=NJ3TQZFfV3q3elNa2NxItYJQTy6CMZkFNGwhlIZAytw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oTq6rl92QjtF9LyJG1zuHCWL9z0PN3kj3ItWHL+poQ4CKCDTVvQXuMKeV7omAG079 A8L0eLtHNrgS21USGn1mmEaLQdRskQobutNrEQkJLt1VnYyGM7XbC0BrHUBdTdFjC0 yQUPQxUkWsaECSup+PnDHhRyV2SsB4sRbAU8GqJ7fpoI3ApW13x62Q00dqv9QyHZjX +SZ1cd+h7r1lEih4uMUidp+oChcTYTVwRsa6rGPtv4PzZviy3kVOY1yOSz67CN/wyW rQ0KSaNncpkrMJJsaBzvrm6gUnyM1F7KXHrJWmibu9KoZnIlKaibe5lzTG1Y+hkyIr 2oYKxMVUDAsXA== Date: Tue, 4 Mar 2025 21:15:22 +0200 From: Jarkko Sakkinen To: Danilo Krummrich Cc: airlied@gmail.com, simona@ffwll.ch, corbet@lwn.net, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, ajanulgu@redhat.com, lyude@redhat.com, pstanner@redhat.com, zhiw@nvidia.com, cjia@nvidia.com, jhubbard@nvidia.com, bskeggs@nvidia.com, acurrid@nvidia.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu, gregkh@linuxfoundation.org, mcgrof@kernel.org, russ.weight@linux.dev, dri-devel@lists.freedesktop.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, nouveau@lists.freedesktop.org, rust-for-linux@vger.kernel.org Subject: Re: [PATCH v5 2/5] rust: firmware: introduce `firmware::ModInfoBuilder` Message-ID: References: <20250304173555.2496-1-dakr@kernel.org> <20250304173555.2496-3-dakr@kernel.org> Precedence: bulk X-Mailing-List: rust-for-linux@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: <20250304173555.2496-3-dakr@kernel.org> On Tue, Mar 04, 2025 at 06:34:49PM +0100, Danilo Krummrich wrote: > The `firmware` field of the `module!` only accepts literal strings, > which is due to the fact that it is implemented as a proc macro. > > Some drivers require a lot of firmware files (such as nova-core) and > hence benefit from more flexibility composing firmware path strings. > > The `firmware::ModInfoBuilder` is a helper component to flexibly compose > firmware path strings for the .modinfo section in const context. > > It is meant to be used in combination with `kernel::module_firmware!`, > which is introduced in a subsequent patch. Ditto. > > Co-developed-by: Alice Ryhl > Signed-off-by: Alice Ryhl > Signed-off-by: Danilo Krummrich > --- > rust/kernel/firmware.rs | 98 +++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 98 insertions(+) > > diff --git a/rust/kernel/firmware.rs b/rust/kernel/firmware.rs > index c5162fdc95ff..6e6972d94597 100644 > --- a/rust/kernel/firmware.rs > +++ b/rust/kernel/firmware.rs > @@ -115,3 +115,101 @@ unsafe impl Send for Firmware {} > // SAFETY: `Firmware` only holds a pointer to a C `struct firmware`, references to which are safe to > // be used from any thread. > unsafe impl Sync for Firmware {} > + > +/// Builder for firmware module info. > +/// > +/// [`ModInfoBuilder`] is a helper component to flexibly compose firmware paths strings for the > +/// .modinfo section in const context. > +/// > +/// It is meant to be used in combination with [`kernel::module_firmware!`]. > +/// > +/// For more details and an example, see [`kernel::module_firmware!`]. > +pub struct ModInfoBuilder { > + buf: [u8; N], > + n: usize, > + module_name: &'static CStr, > +} > + > +impl ModInfoBuilder { > + /// Create an empty builder instance. > + pub const fn new(module_name: &'static CStr) -> Self { > + Self { > + buf: [0; N], > + n: 0, > + module_name, > + } > + } > + > + const fn push_internal(mut self, bytes: &[u8]) -> Self { > + let mut j = 0; > + > + if N == 0 { > + self.n += bytes.len(); > + return self; > + } > + > + while j < bytes.len() { > + if self.n < N { > + self.buf[self.n] = bytes[j]; > + } > + self.n += 1; > + j += 1; > + } > + self > + } > + > + /// Push an additional path component. > + /// > + /// After a new [`ModInfoBuilder`] instance has been created, [`ModInfoBuilder::prepare`] must > + /// be called before adding path components. > + pub const fn push(self, s: &str) -> Self { > + if N != 0 && self.n == 0 { > + crate::build_error!("Must call prepare() before push()."); > + } > + > + self.push_internal(s.as_bytes()) > + } > + > + const fn prepare_module_name(self) -> Self { > + let mut this = self; > + let module_name = this.module_name; > + > + if !this.module_name.is_empty() { > + this = this.push_internal(module_name.as_bytes_with_nul()); > + > + if N != 0 { > + // Re-use the space taken by the NULL terminator and swap it with the '.' separator. > + this.buf[this.n - 1] = b'.'; > + } > + } > + > + this.push_internal(b"firmware=") > + } > + > + /// Prepare for the next module info entry. > + /// > + /// Must be called before [`ModInfoBuilder::push`] can be called. > + pub const fn prepare(self) -> Self { > + self.push_internal(b"\0").prepare_module_name() > + } > + > + /// Build the byte array. > + pub const fn build(self) -> [u8; N] { > + // Add the final NULL terminator. > + let this = self.push_internal(b"\0"); > + > + if this.n == N { > + this.buf > + } else { > + crate::build_error!("Length mismatch."); > + } > + } > +} > + > +impl ModInfoBuilder<0> { > + /// Return the length of the byte array to build. > + pub const fn build_length(self) -> usize { > + // Compensate for the NULL terminator added by `build`. > + self.n + 1 > + } > +} > -- > 2.48.1 > > BR, Jarkko