Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932209Ab3CTKyB (ORCPT ); Wed, 20 Mar 2013 06:54:01 -0400 Received: from metis.ext.pengutronix.de ([92.198.50.35]:37970 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756739Ab3CTKw6 (ORCPT ); Wed, 20 Mar 2013 06:52:58 -0400 From: Philipp Zabel To: linux-kernel@vger.kernel.org Cc: Arnd Bergmann , Greg Kroah-Hartman , Grant Likely , Rob Herring , Paul Gortmaker , Shawn Guo , Huang Shijie , Dong Aisheng , Matt Porter , Fabio Estevam , Javier Martin , kernel@pengutronix.de, devicetree-discuss@lists.ozlabs.org, Philipp Zabel Subject: [PATCH v9 RESEND 2/4] misc: Generic on-chip SRAM allocation driver Date: Wed, 20 Mar 2013 11:52:45 +0100 Message-Id: <1363776767-2635-3-git-send-email-p.zabel@pengutronix.de> X-Mailer: git-send-email 1.8.2.rc2 In-Reply-To: <1363776767-2635-1-git-send-email-p.zabel@pengutronix.de> References: <1363776767-2635-1-git-send-email-p.zabel@pengutronix.de> X-SA-Exim-Connect-IP: 10.1.0.7 X-SA-Exim-Mail-From: p.zabel@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6203 Lines: 214 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 -- 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/