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From: Murali Karicheri <m-karicheri2@ti.com>
To: Robin Murphy <robin.murphy@arm.com>
Cc: "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	Russell King <linux@arm.linux.org.uk>,
	Arnd Bergmann <arnd@arndb.de>, Joerg Roedel <joro@8bytes.org>,
	Will Deacon <Will.Deacon@arm.com>,
	Rob Herring <robh+dt@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	"suravee.suthikulpanit@amd.com" <suravee.suthikulpanit@amd.com>,
	"grant.likely@linaro.org" <grant.likely@linaro.org>
Subject: Re: [PATCH v4 3/6] of: fix size when dma-range is not used
Date: Tue, 27 Jan 2015 13:55:15 -0500	[thread overview]
Message-ID: <54C7DF13.20402@ti.com> (raw)
In-Reply-To: <54C77616.80301@arm.com>

On 01/27/2015 06:27 AM, Robin Murphy wrote:
> Hi Murali,
>
> On 23/01/15 22:32, Murali Karicheri wrote:
>> Fix the dma-range size when the DT attribute is missing. i.e set size to
>> dev->coherent_dma_mask + 1 instead of dev->coherent_dma_mask. To detect
>> overflow when mask is set to max of u64, add a check, log error and
>> return.
>> Some platform use mask format for size in DTS. So add a work around to
>> catch this and fix.
>>
>> Cc: Joerg Roedel <joro@8bytes.org>
>> Cc: Grant Likely <grant.likely@linaro.org>
>> Cc: Rob Herring <robh+dt@kernel.org>
>> Cc: Bjorn Helgaas <bhelgaas@google.com>
>> Cc: Will Deacon <will.deacon@arm.com>
>> Cc: Russell King <linux@arm.linux.org.uk>
>> Cc: Arnd Bergmann <arnd@arndb.de>
>> Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
>>
>> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
>> ---
>> drivers/of/device.c | 14 +++++++++++++-
>> 1 file changed, 13 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/of/device.c b/drivers/of/device.c
>> index 2de320d..0a5ff54 100644
>> --- a/drivers/of/device.c
>> +++ b/drivers/of/device.c
>> @@ -105,12 +105,24 @@ void of_dma_configure(struct device *dev, struct
>> device_node *np)
>> ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
>> if (ret < 0) {
>> dma_addr = offset = 0;
>> - size = dev->coherent_dma_mask;
>> + size = dev->coherent_dma_mask + 1;
>> } else {
>> offset = PFN_DOWN(paddr - dma_addr);
>> + /*
>> + * Add a work around to treat the size as mask + 1 in case
>> + * it is defined in DT as a mask.
>> + */
>> + if (size & 1)
>> + size = size + 1;
>> dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
>> }
>>
>> + /* if size is 0, we have an overflow of u64 */
>> + if (!size) {
>> + dev_err(dev, "invalid size\n");
>> + return;
>> + }
>> +
>
> This seems potentially fragile to dodgy DTs given that we might also be
> using size to make a mask later. Would it make sense to double-up a
> sanity check as mask-format detection? Something like:
>
> if is_power_of_2(size)
> // use size
> else if is_power_of_2(size + 1)
> // use size + 1
> else
> // cry
Robin,

How about having the logic like this?

	ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
	if (ret < 0) {
		dma_addr = offset = 0;
		size = dev->coherent_dma_mask + 1;
	} else {
		offset = PFN_DOWN(paddr - dma_addr);
		dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
	}

	if (is_power_of_2(size + 1))
		size = size + 1;
	else if (!is_power_of_2(size))
	{
		dev_err(dev, "invalid size\n");
		return;
	}

Murali
>
>
> Robin.
>
>> dev->dma_pfn_offset = offset;
>>
>> coherent = of_dma_is_coherent(np);
>>
>
>


-- 
Murali Karicheri
Linux Kernel, Texas Instruments

  parent reply	other threads:[~2015-01-27 18:56 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-23 22:32 [PATCH v4 0/6] PCI: get DMA configuration from parent device Murali Karicheri
2015-01-23 22:32 ` [PATCH v4 1/6] of: iommu: add ptr to OF node arg to of_iommu_configure() Murali Karicheri
2015-01-25 13:32   ` Laurent Pinchart
2015-01-26 18:49     ` Murali Karicheri
2015-01-28 11:33       ` Will Deacon
2015-01-28 12:23         ` Laurent Pinchart
2015-01-28 12:29           ` Will Deacon
2015-01-28 13:15             ` Laurent Pinchart
2015-01-28 13:32               ` Will Deacon
2015-01-28 15:21                 ` Murali Karicheri
2015-01-28 23:32                 ` Laurent Pinchart
2015-01-29 14:59                   ` Murali Karicheri
2015-01-29 16:49                   ` Rob Herring
2015-01-30  0:24                     ` Laurent Pinchart
2015-01-30 15:23                       ` Murali Karicheri
2015-01-23 22:32 ` [PATCH v4 2/6] of: move of_dma_configure() to device.c to help re-use Murali Karicheri
2015-01-23 22:32 ` [PATCH v4 3/6] of: fix size when dma-range is not used Murali Karicheri
2015-01-27 11:27   ` Robin Murphy
2015-01-27 15:44     ` Murali Karicheri
2015-01-27 18:55     ` Murali Karicheri [this message]
2015-01-28 11:05       ` Catalin Marinas
2015-01-28 15:45         ` Rob Herring
2015-01-28 17:23           ` Catalin Marinas
2015-01-28 17:34           ` Murali Karicheri
2015-01-28 15:55         ` Robin Murphy
2015-01-28 17:30           ` Catalin Marinas
2015-01-30 18:06             ` Murali Karicheri
2015-02-02 12:18               ` Catalin Marinas
2015-02-02 16:10                 ` Murali Karicheri
2015-02-05 21:42                 ` Murali Karicheri
2015-02-05 22:44                   ` Catalin Marinas
2015-01-23 22:32 ` [PATCH v4 4/6] of/pci: add of_pci_dma_configure() update dma configuration Murali Karicheri
2015-01-23 23:41   ` Bjorn Helgaas
2015-01-26 23:25     ` Murali Karicheri
2015-01-26 23:59       ` Bjorn Helgaas
2015-01-27 18:14         ` Murali Karicheri
2015-01-27 18:42           ` Bjorn Helgaas
2015-01-27 18:45             ` Murali Karicheri
2015-01-23 22:32 ` [PATCH v4 5/6] PCI: update dma configuration from DT Murali Karicheri
2015-01-23 23:27   ` Bjorn Helgaas
2015-01-26 23:28     ` Murali Karicheri
2015-01-23 22:32 ` [PATCH v4 6/6] arm: dma-mapping: updates to limit dma_mask and iommu mapping size Murali Karicheri
2015-01-27 11:12   ` Robin Murphy
2015-01-27 11:34     ` Catalin Marinas
2015-01-27 15:19       ` Murali Karicheri

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