Re: Bug 205201 - Booting halts if Dawicontrol DC-2976 UW SCSI board installed, unless RAM size limited to 3500M

From: Christian Zigotzky
Date: Thu Nov 21 2019 - 11:35:06 EST


Am 21.11.19 um 14:33 schrieb Robin Murphy:
On 21/11/2019 12:21 pm, Christian Zigotzky wrote:
On 21 November 2019 at 01:16 pm, Christian Zigotzky wrote:
On 21 November 2019 at 08:29 am, Christoph Hellwig wrote:
On Sat, Nov 16, 2019 at 08:06:05AM +0100, Christian Zigotzky wrote:
/*
 * DMA addressing mode.
 *
 * 0 : 32 bit addressing for all chips.
 * 1 : 40 bit addressing when supported by chip.
 * 2 : 64 bit addressing when supported by chip,
 * limited to 16 segments of 4 GB -> 64 GB max.
 */
#defineÂÂ SYM_CONF_DMA_ADDRESSING_MODE CONFIG_SCSI_SYM53C8XX_DMA_ADDRESSING_MODE

Cyrus config:

CONFIG_SCSI_SYM53C8XX_DMA_ADDRESSING_MODE=1

I will configure â0 : 32 bit addressing for all chipsâ for the RC8. Maybe this is the solution.
0 means you are going to do bounce buffering a lot, which seems
generally like a bad idea.

But why are we talking about the sym53c8xx driver now? The last issue
you reported was about video4linux allocations.

Both drivers have the same problem. They don't work if we have more than 3.5GB RAM. I try to find a solution until you have a good solution. I have already a solution for V4L but I still need one for the sym53c8xx driver.
OK, you mean that "0" is a bad idea but maybe it works until you have a solution. ;-)

Is this on the same machine with the funny non-power-of-two bus_dma_mask as your other report? If so, does Nicolas' latest patch[1] help at all?

Robin.

[1] https://lore.kernel.org/linux-iommu/20191121092646.8449-1-nsaenzjulienne@xxxxxxx/T/#u

Robin,

I modified the patch and compiled a new RC8 of kernel 5.4 today. (patch attached)

We have to wait to Rolands test results with his SCSI PCI card. I tested it today but my TV card doesn't work with this patch.

Thanks
diff -rupN a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c
--- a/arch/powerpc/sysdev/fsl_pci.c 2019-11-17 23:47:30.000000000 +0100
+++ b/arch/powerpc/sysdev/fsl_pci.c 2019-11-21 15:32:50.216488955 +0100
@@ -115,8 +115,8 @@ static void pci_dma_dev_setup_swiotlb(st
{
struct pci_controller *hose = pci_bus_to_host(pdev->bus);

- pdev->dev.bus_dma_mask =
- hose->dma_window_base_cur + hose->dma_window_size;
+ pdev->dev.bus_dma_limit =
+ hose->dma_window_base_cur + hose->dma_window_size - 1;
}

static void setup_swiotlb_ops(struct pci_controller *hose)
@@ -135,7 +135,7 @@ static void fsl_pci_dma_set_mask(struct
* mapping that allows addressing any RAM address from across PCI.
*/
if (dev_is_pci(dev) && dma_mask >= pci64_dma_offset * 2 - 1) {
- dev->bus_dma_mask = 0;
+ dev->bus_dma_limit = 0;
dev->archdata.dma_offset = pci64_dma_offset;
}
}
diff -rupN a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
--- a/drivers/iommu/dma-iommu.c 2019-11-17 23:47:30.000000000 +0100
+++ b/drivers/iommu/dma-iommu.c 2019-11-21 15:32:50.216488955 +0100
@@ -405,8 +405,7 @@ static dma_addr_t iommu_dma_alloc_iova(s
if (iova_len < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1)))
iova_len = roundup_pow_of_two(iova_len);

- if (dev->bus_dma_mask)
- dma_limit &= dev->bus_dma_mask;
+ dma_limit = min_not_zero(dma_limit, dev->bus_dma_limit);

if (domain->geometry.force_aperture)
dma_limit = min(dma_limit, domain->geometry.aperture_end);
diff -rupN a/drivers/of/device.c b/drivers/of/device.c
--- a/drivers/of/device.c 2019-11-17 23:47:30.000000000 +0100
+++ b/drivers/of/device.c 2019-11-21 15:32:50.216488955 +0100
@@ -93,7 +93,7 @@ int of_dma_configure(struct device *dev,
bool coherent;
unsigned long offset;
const struct iommu_ops *iommu;
- u64 mask;
+ u64 mask, end;

ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
if (ret < 0) {
@@ -148,12 +148,13 @@ int of_dma_configure(struct device *dev,
* Limit coherent and dma mask based on size and default mask
* set by the driver.
*/
- mask = DMA_BIT_MASK(ilog2(dma_addr + size - 1) + 1);
+ end = dma_addr + size - 1;
+ mask = DMA_BIT_MASK(ilog2(end) + 1);
dev->coherent_dma_mask &= mask;
*dev->dma_mask &= mask;
- /* ...but only set bus mask if we found valid dma-ranges earlier */
+ /* ...but only set bus limit if we found valid dma-ranges earlier */
if (!ret)
- dev->bus_dma_mask = mask;
+ dev->bus_dma_limit = end;

coherent = of_dma_is_coherent(np);
dev_dbg(dev, "device is%sdma coherent\n",
diff -rupN a/include/linux/device.h b/include/linux/device.h
--- a/include/linux/device.h 2019-11-17 23:47:30.000000000 +0100
+++ b/include/linux/device.h 2019-11-21 15:32:50.216488955 +0100
@@ -1186,8 +1186,8 @@ struct dev_links_info {
* @coherent_dma_mask: Like dma_mask, but for alloc_coherent mapping as not all
* hardware supports 64-bit addresses for consistent allocations
* such descriptors.
- * @bus_dma_mask: Mask of an upstream bridge or bus which imposes a smaller DMA
- * limit than the device itself supports.
+ * @bus_dma_limit: Limit of an upstream bridge or bus which imposes a smaller
+ * DMA limit than the device itself supports.
* @dma_pfn_offset: offset of DMA memory range relatively of RAM
* @dma_parms: A low level driver may set these to teach IOMMU code about
* segment limitations.
@@ -1270,7 +1270,7 @@ struct device {
not all hardware supports
64 bit addresses for consistent
allocations such descriptors. */
- u64 bus_dma_mask; /* upstream dma_mask constraint */
+ u64 bus_dma_limit; /* upstream dma constraint */
unsigned long dma_pfn_offset;

struct device_dma_parameters *dma_parms;
diff -rupN a/include/linux/dma-direct.h b/include/linux/dma-direct.h
--- a/include/linux/dma-direct.h 2019-11-17 23:47:30.000000000 +0100
+++ b/include/linux/dma-direct.h 2019-11-21 15:37:40.091564417 +0100
@@ -28,7 +28,7 @@ static inline bool dma_capable(struct de
return false;

return addr + size - 1 <=
- min_not_zero(*dev->dma_mask, dev->bus_dma_mask);
+ min_not_zero(*dev->dma_mask, dev->bus_dma_limit);
}
#endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */

diff -rupN a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
--- a/include/linux/dma-mapping.h 2019-11-17 23:47:30.000000000 +0100
+++ b/include/linux/dma-mapping.h 2019-11-21 15:32:50.220488949 +0100
@@ -693,7 +693,7 @@ static inline int dma_coerce_mask_and_co
*/
static inline bool dma_addressing_limited(struct device *dev)
{
- return min_not_zero(dma_get_mask(dev), dev->bus_dma_mask) <
+ return min_not_zero(dma_get_mask(dev), dev->bus_dma_limit) <
dma_get_required_mask(dev);
}

diff -rupN a/kernel/dma/direct.c b/kernel/dma/direct.c
--- a/kernel/dma/direct.c 2019-11-17 23:47:30.000000000 +0100
+++ b/kernel/dma/direct.c 2019-11-21 15:50:09.570609847 +0100
@@ -27,10 +27,10 @@ static void report_addr(struct device *d
{
if (!dev->dma_mask) {
dev_err_once(dev, "DMA map on device without dma_mask\n");
- } else if (*dev->dma_mask >= DMA_BIT_MASK(32) || dev->bus_dma_mask) {
+ } else if (*dev->dma_mask >= DMA_BIT_MASK(32) || dev->bus_dma_limit) {
dev_err_once(dev,
- "overflow %pad+%zu of DMA mask %llx bus mask %llx\n",
- &dma_addr, size, *dev->dma_mask, dev->bus_dma_mask);
+ "overflow %pad+%zu of DMA mask %llx bus limit %llx\n",
+ &dma_addr, size, *dev->dma_mask, dev->bus_dma_limit);
}
WARN_ON_ONCE(1);
}
@@ -51,15 +51,14 @@ u64 dma_direct_get_required_mask(struct
}

static gfp_t __dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,
- u64 *phys_mask)
+ u64 *phys_limit)
{
- if (dev->bus_dma_mask && dev->bus_dma_mask < dma_mask)
- dma_mask = dev->bus_dma_mask;
+ u64 dma_limit = min_not_zero(dma_mask, dev->bus_dma_limit);

if (force_dma_unencrypted(dev))
- *phys_mask = __dma_to_phys(dev, dma_mask);
+ *phys_limit = __dma_to_phys(dev, dma_limit);
else
- *phys_mask = dma_to_phys(dev, dma_mask);
+ *phys_limit = dma_to_phys(dev, dma_limit);

/*
* Optimistically try the zone that the physical address mask falls
@@ -69,9 +68,9 @@ static gfp_t __dma_direct_optimal_gfp_ma
* Note that GFP_DMA32 and GFP_DMA are no ops without the corresponding
* zones.
*/
- if (*phys_mask <= DMA_BIT_MASK(ARCH_ZONE_DMA_BITS))
+ if (*phys_limit <= DMA_BIT_MASK(ARCH_ZONE_DMA_BITS))
return GFP_DMA;
- if (*phys_mask <= DMA_BIT_MASK(32))
+ if (*phys_limit <= DMA_BIT_MASK(32))
return GFP_DMA32;
return 0;
}
@@ -79,7 +78,7 @@ static gfp_t __dma_direct_optimal_gfp_ma
static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
{
return phys_to_dma_direct(dev, phys) + size - 1 <=
- min_not_zero(dev->coherent_dma_mask, dev->bus_dma_mask);
+ min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit);
}

struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
@@ -88,7 +87,7 @@ struct page *__dma_direct_alloc_pages(st
size_t alloc_size = PAGE_ALIGN(size);
int node = dev_to_node(dev);
struct page *page = NULL;
- u64 phys_mask;
+ u64 phys_limit;

if (attrs & DMA_ATTR_NO_WARN)
gfp |= __GFP_NOWARN;
@@ -96,7 +95,7 @@ struct page *__dma_direct_alloc_pages(st
/* we always manually zero the memory once we are done: */
gfp &= ~__GFP_ZERO;
gfp |= __dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
- &phys_mask);
+ &phys_limit);
page = dma_alloc_contiguous(dev, alloc_size, gfp);
if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
dma_free_contiguous(dev, page, alloc_size);
@@ -110,7 +109,7 @@ again:
page = NULL;

if (IS_ENABLED(CONFIG_ZONE_DMA32) &&
- phys_mask < DMA_BIT_MASK(64) &&
+ phys_limit < DMA_BIT_MASK(64) &&
!(gfp & (GFP_DMA32 | GFP_DMA))) {
gfp |= GFP_DMA32;
goto again;
diff -rupN a/arch/powerpc/include/asm/dma-direct.h b/arch/powerpc/include/asm/dma-direct.h
--- a/arch/powerpc/include/asm/dma-direct.h 2019-11-17 23:47:30.000000000 +0100
+++ b/arch/powerpc/include/asm/dma-direct.h 2019-11-21 16:18:13.316815445 +0100
@@ -8,7 +8,7 @@ static inline bool dma_capable(struct de
return false;

return addr + size - 1 <=
- min_not_zero(*dev->dma_mask, dev->bus_dma_mask);
+ min_not_zero(*dev->dma_mask, dev->bus_dma_limit);
}

static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)