From: "Rafael J. Wysocki" Subject: Re: [V5 PATCH 1/5] ACPI / scan: Parse _CCA and setup device coherency Date: Sat, 23 May 2015 03:25:21 +0200 Message-ID: <9319342.HPcAml3MbA@vostro.rjw.lan> References: <1432159758-4486-1-git-send-email-Suravee.Suthikulpanit@amd.com> <2939517.7sXtxU6TkU@vostro.rjw.lan> <555FC695.1000404@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7Bit Cc: lenb@kernel.org, catalin.marinas@arm.com, will.deacon@arm.com, thomas.lendacky@amd.com, herbert@gondor.apana.org.au, davem@davemloft.net, arnd@arndb.de, msalter@redhat.com, hanjun.guo@linaro.org, al.stone@linaro.org, grant.likely@linaro.org, leo.duran@amd.com, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linaro-acpi@lists.linaro.org, netdev@vger.kernel.org, linux-crypto@vger.kernel.org To: Suravee Suthikulanit Return-path: In-Reply-To: <555FC695.1000404@amd.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org On Friday, May 22, 2015 07:15:17 PM Suravee Suthikulanit wrote: > On 5/22/2015 6:05 PM, Rafael J. Wysocki wrote: > > On Friday, May 22, 2015 05:24:15 PM Suravee Suthikulanit wrote: > >> Not sure if this went out earlier. So I am resending. > >> > >> On 5/22/15 16:56, Rafael J. Wysocki wrote: > >>>> diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c > >>>>> index 39c485b..b9657af 100644 > >>>>> --- a/drivers/acpi/glue.c > >>>>> +++ b/drivers/acpi/glue.c > >>>>> @@ -13,6 +13,7 @@ > >>>>> #include > >>>>> #include > >>>>> #include > >>>>> +#include > >>>>> > >>>>> #include "internal.h" > >>>>> > >>>>> @@ -167,6 +168,7 @@ int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev) > >>>>> struct list_head *physnode_list; > >>>>> unsigned int node_id; > >>>>> int retval = -EINVAL; > >>>>> + bool coherent; > >>>>> > >>>>> if (has_acpi_companion(dev)) { > >>>>> if (acpi_dev) { > >>>>> @@ -223,6 +225,9 @@ int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev) > >>>>> if (!has_acpi_companion(dev)) > >>>>> ACPI_COMPANION_SET(dev, acpi_dev); > >>>>> > >>>>> + if (acpi_check_dma(acpi_dev, &coherent)) > >>>>> + arch_setup_dma_ops(dev, 0, 0, NULL, coherent); > >>>>> + > >>> Well, so is this going to work for PCI too after all? > >>> > >> > >> No, as Bjorn suggested, PCI changes for setting DMA coherent from _CCA > >> (patch 3/6 in V4) will be submitted separately. We are working on > >> cleaning up and up-streaming the PCI ACPI support for ARM64. > > > > OK, but acpi_bind_one() is called for PCI devices too. Won't that be a problem? > > > > > > > In this case, we would be going through the following call path: > > --> pci_device_add() > |--> pci_dma_configure() ** 1 ** > |--> device_add() > |--> platform_notify() > |--> acpi_platform_notify() > |--> acpi_bind_one() ** 2 ** > > At (1), we would be calling arch_setup_dma_ops() with the PCI host > bridge _CCA information. So, it should have already taken care of > setting up device coherency here. > > At (2), if there is no acpi_dev for endpoint devices (which I believe > this is normally the case), it would return early and skip > arch_setup_dma_ops(). That's not correct. There may be ACPI companions for endpoint devices too. > At (2), if there is an acpi_dev, the coherent_dma flag should have > already been setup by the acpi_init_device_object during ACPI scan. That one sets the flag for the *ACPI* *companion* of the device, which I'm still thinking is pointless, isn't it? > However, I am not certain about this case since I don't have the DSDT > containing PCI endpoint devices to test with. Every x86 PC has them (as far as I can say), but in that case there's no _CCA and they are all coherent. -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.