Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933307Ab3CVMrs (ORCPT ); Fri, 22 Mar 2013 08:47:48 -0400 Received: from mail-wi0-f170.google.com ([209.85.212.170]:55150 "EHLO mail-wi0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751186Ab3CVMrq (ORCPT ); Fri, 22 Mar 2013 08:47:46 -0400 MIME-Version: 1.0 In-Reply-To: <1363776767-2635-3-git-send-email-p.zabel@pengutronix.de> References: <1363776767-2635-1-git-send-email-p.zabel@pengutronix.de> <1363776767-2635-3-git-send-email-p.zabel@pengutronix.de> Date: Fri, 22 Mar 2013 13:47:44 +0100 Message-ID: Subject: Re: [PATCH v9 RESEND 2/4] misc: Generic on-chip SRAM allocation driver From: Michal Simek To: Philipp Zabel Cc: linux-kernel@vger.kernel.org, Fabio Estevam , Matt Porter , Dong Aisheng , Greg Kroah-Hartman , devicetree-discuss@lists.ozlabs.org, Rob Herring , Paul Gortmaker , Javier Martin , kernel@pengutronix.de, Huang Shijie Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7535 Lines: 231 2013/3/20 Philipp Zabel : > This driver requests and remaps a memory region as configured in the > device tree. It serves memory from this region via the genalloc API. > It optionally enables the SRAM clock. > > Other drivers can retrieve the genalloc pool from a phandle pointing > to this drivers' device node in the device tree. > > The allocation granularity is hard-coded to 32 bytes for now, > to make the SRAM driver useful for the 6502 remoteproc driver. > There is overhead for bigger SRAMs, where only a much coarser > allocation granularity is needed: At 32 bytes minimum allocation > size, a 256 KiB SRAM needs a 1 KiB bitmap to track allocations. > > Signed-off-by: Philipp Zabel > Reviewed-by: Shawn Guo > Acked-by: Grant Likely > --- > Changes since v8: > - Changed device tree compatible string to "mmio-sram" > --- > Documentation/devicetree/bindings/misc/sram.txt | 16 +++ > drivers/misc/Kconfig | 9 ++ > drivers/misc/Makefile | 1 + > drivers/misc/sram.c | 121 +++++++++++++++++++++++ > 4 files changed, 147 insertions(+) > create mode 100644 Documentation/devicetree/bindings/misc/sram.txt > create mode 100644 drivers/misc/sram.c > > diff --git a/Documentation/devicetree/bindings/misc/sram.txt b/Documentation/devicetree/bindings/misc/sram.txt > new file mode 100644 > index 0000000..4d0a00e > --- /dev/null > +++ b/Documentation/devicetree/bindings/misc/sram.txt > @@ -0,0 +1,16 @@ > +Generic on-chip SRAM > + > +Simple IO memory regions to be managed by the genalloc API. > + > +Required properties: > + > +- compatible : mmio-sram > + > +- reg : SRAM iomem address range > + > +Example: > + > +sram: sram@5c000000 { > + compatible = "mmio-sram"; > + reg = <0x5c000000 0x40000>; /* 256 KiB SRAM at address 0x5c000000 */ > +}; > diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig > index e83fdfe..4878507 100644 > --- a/drivers/misc/Kconfig > +++ b/drivers/misc/Kconfig > @@ -510,6 +510,15 @@ config LATTICE_ECP3_CONFIG > > If unsure, say N. > > +config SRAM > + bool "Generic on-chip SRAM driver" > + depends on HAS_IOMEM > + select GENERIC_ALLOCATOR > + help > + This driver allows to declare a memory region to be managed > + by the genalloc API. It is supposed to be used for small > + on-chip SRAM areas found on many SoCs. > + > source "drivers/misc/c2port/Kconfig" > source "drivers/misc/eeprom/Kconfig" > source "drivers/misc/cb710/Kconfig" > diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile > index 35a1463..08e2007 100644 > --- a/drivers/misc/Makefile > +++ b/drivers/misc/Makefile > @@ -52,3 +52,4 @@ obj-$(CONFIG_INTEL_MEI) += mei/ > obj-$(CONFIG_MAX8997_MUIC) += max8997-muic.o > obj-$(CONFIG_VMWARE_VMCI) += vmw_vmci/ > obj-$(CONFIG_LATTICE_ECP3_CONFIG) += lattice-ecp3-config.o > +obj-$(CONFIG_SRAM) += sram.o > diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c > new file mode 100644 > index 0000000..7858c62 > --- /dev/null > +++ b/drivers/misc/sram.c > @@ -0,0 +1,121 @@ > +/* > + * Generic on-chip SRAM allocation driver > + * > + * Copyright (C) 2012 Philipp Zabel, Pengutronix > + * > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License > + * as published by the Free Software Foundation; either version 2 > + * of the License, or (at your option) any later version. > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program; if not, write to the Free Software > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, > + * MA 02110-1301, USA. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define SRAM_GRANULARITY 32 > + > +struct sram_dev { > + struct gen_pool *pool; > + struct clk *clk; > +}; > + > +static int sram_probe(struct platform_device *pdev) > +{ > + void __iomem *virt_base; > + struct sram_dev *sram; > + struct resource *res; > + unsigned long size; > + int ret; > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + if (!res) > + return -EINVAL; > + > + size = resource_size(res); > + > + virt_base = devm_request_and_ioremap(&pdev->dev, res); > + if (!virt_base) > + return -EADDRNOTAVAIL; > + > + sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL); > + if (!sram) > + return -ENOMEM; > + > + sram->clk = devm_clk_get(&pdev->dev, NULL); > + if (IS_ERR(sram->clk)) > + sram->clk = NULL; > + else > + clk_prepare_enable(sram->clk); > + > + sram->pool = devm_gen_pool_create(&pdev->dev, ilog2(SRAM_GRANULARITY), -1); > + if (!sram->pool) > + return -ENOMEM; > + > + ret = gen_pool_add_virt(sram->pool, (unsigned long)virt_base, > + res->start, size, -1); > + if (ret < 0) { > + gen_pool_destroy(sram->pool); > + return ret; > + } > + > + platform_set_drvdata(pdev, sram); > + > + dev_dbg(&pdev->dev, "SRAM pool: %ld KiB @ 0x%p\n", size / 1024, virt_base); > + > + return 0; > +} > + > +static int sram_remove(struct platform_device *pdev) > +{ > + struct sram_dev *sram = platform_get_drvdata(pdev); > + > + if (gen_pool_avail(sram->pool) < gen_pool_size(sram->pool)) > + dev_dbg(&pdev->dev, "removed while SRAM allocated\n"); > + > + gen_pool_destroy(sram->pool); > + > + if (sram->clk) > + clk_disable_unprepare(sram->clk); > + > + return 0; > +} > + > +#ifdef CONFIG_OF > +static struct of_device_id sram_dt_ids[] = { > + { .compatible = "mmio-sram" }, > + {} > +}; > +#endif > + > +static struct platform_driver sram_driver = { > + .driver = { > + .name = "sram", > + .of_match_table = of_match_ptr(sram_dt_ids), > + }, > + .probe = sram_probe, > + .remove = sram_remove, > +}; > + > +int __init sram_init(void) > +{ > + return platform_driver_register(&sram_driver); > +} > + > +postcore_initcall(sram_init); > -- > 1.7.10.4 Tested on xilinx-zynq with OCM. Tested-by: Michal Simek Thanks, Michal -- Michal Simek, Ing. (M.Eng) w: www.monstr.eu p: +42-0-721842854 Maintainer of Linux kernel - Microblaze cpu - http://www.monstr.eu/fdt/ Maintainer of Linux kernel - Xilinx Zynq ARM architecture Microblaze U-BOOT custodian and responsible for u-boot arm zynq platform -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/