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[128.2.16.51]) by smtp.gmail.com with ESMTPSA id b10sm11909098qkh.69.2019.11.20.09.23.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 Nov 2019 09:23:03 -0800 (PST) Date: Wed, 20 Nov 2019 12:23:00 -0500 From: "Gabriel L. Somlo" To: Mateusz Holenko Cc: Rob Herring , Mark Rutland , Greg Kroah-Hartman , Jiri Slaby , devicetree@vger.kernel.org, linux-serial@vger.kernel.org, Stafford Horne , Karol Gugala , Mateusz Holenko , Mauro Carvalho Chehab , "David S. Miller" , "Paul E. McKenney" , Filip Kokosinski , Joel Stanley , Jonathan Cameron , Maxime Ripard , Shawn Guo , Heiko Stuebner , Sam Ravnborg , Icenowy Zheng , Laurent Pinchart , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/4] litex: add common LiteX header Message-ID: <20191120172300.GA15391@hedwig.ini.cmu.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191023114634.13657-2-mholenko@antmicro.com> X-Clacks-Overhead: GNU Terry Pratchett User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-serial-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org > It provides helper CSR access functions used by all > LiteX drivers. > > Signed-off-by: Mateusz Holenko > --- > This commit has been introduced in v2 of the patchset. > > MAINTAINERS | 6 +++++ > include/linux/litex.h | 59 +++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 65 insertions(+) > create mode 100644 include/linux/litex.h > > diff --git a/MAINTAINERS b/MAINTAINERS > index 296de2b51c83..eaa51209bfb2 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -9493,6 +9493,12 @@ F: Documentation/misc-devices/lis3lv02d.rst > F: drivers/misc/lis3lv02d/ > F: drivers/platform/x86/hp_accel.c > > +LITEX PLATFORM > +M: Karol Gugala > +M: Mateusz Holenko > +S: Maintained > +F: include/linux/litex.h > + > LIVE PATCHING > M: Josh Poimboeuf > M: Jiri Kosina > diff --git a/include/linux/litex.h b/include/linux/litex.h > new file mode 100644 > index 000000000000..e793d2d7c881 > --- /dev/null > +++ b/include/linux/litex.h > @@ -0,0 +1,59 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Common LiteX header providing > + * helper functions for accessing CSRs. > + * > + * Copyright (C) 2019 Antmicro > + */ > + > +#ifndef _LINUX_LITEX_H > +#define _LINUX_LITEX_H > + > +#include > +#include > +#include > + > +#define LITEX_REG_SIZE 0x4 > +#define LITEX_SUBREG_SIZE 0x1 > +#define LITEX_SUBREG_SIZE_BIT (LITEX_SUBREG_SIZE * 8) Please be aware that LiteX supports "LITEX_SUBREG_SIZE" of up to 4, and might go even as far as 8 in the near future. Hard coding this here might be short sighted. A good alternative might be to have "litex_subreg_size" or "mmio-dw-bytes" passed in via a DT property of the SoC node, as illustrated here: https://github.com/litex-hub/linux-on-litex-vexriscv/pull/60 Thanks, --Gabriel > + > +#ifdef __LITTLE_ENDIAN > +# define LITEX_READ_REG(addr) ioread32(addr) > +# define LITEX_READ_REG_OFF(addr, off) ioread32(addr + off) > +# define LITEX_WRITE_REG(val, addr) iowrite32(val, addr) > +# define LITEX_WRITE_REG_OFF(val, addr, off) iowrite32(val, addr + off) > +#else > +# define LITEX_READ_REG(addr) ioread32be(addr) > +# define LITEX_READ_REG_OFF(addr, off) ioread32be(addr + off) > +# define LITEX_WRITE_REG(val, addr) iowrite32be(val, addr) > +# define LITEX_WRITE_REG_OFF(val, addr, off) iowrite32be(val, addr + off) > +#endif > + > +/* Helper functions for manipulating LiteX registers */ > + > +static inline void litex_set_reg(void __iomem *reg, u32 reg_size, u32 val) > +{ > + u32 shifted_data, shift, i; > + > + for (i = 0; i < reg_size; ++i) { > + shift = ((reg_size - i - 1) * LITEX_SUBREG_SIZE_BIT); > + shifted_data = val >> shift; > + LITEX_WRITE_REG(shifted_data, reg + (LITEX_REG_SIZE * i)); > + } > +} > + > +static inline u32 litex_get_reg(void __iomem *reg, u32 reg_size) > +{ > + u32 shifted_data, shift, i; > + u32 result = 0; > + > + for (i = 0; i < reg_size; ++i) { > + shifted_data = LITEX_READ_REG(reg + (LITEX_REG_SIZE * i)); > + shift = ((reg_size - i - 1) * LITEX_SUBREG_SIZE_BIT); > + result |= (shifted_data << shift); > + } > + > + return result; > +} > + > +#endif /* _LINUX_LITEX_H */