diff options
Diffstat (limited to 'drivers/spi/spi-atmel.c')
| -rw-r--r-- | drivers/spi/spi-atmel.c | 30 |
1 files changed, 26 insertions, 4 deletions
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c index 1eb83c9613d5..f95da364c283 100644 --- a/drivers/spi/spi-atmel.c +++ b/drivers/spi/spi-atmel.c @@ -269,6 +269,7 @@ struct atmel_spi_caps { bool is_spi2; bool has_wdrbt; bool has_dma_support; + bool has_pdc_support; }; /* @@ -1422,11 +1423,31 @@ static void atmel_get_caps(struct atmel_spi *as) unsigned int version; version = atmel_get_version(as); - dev_info(&as->pdev->dev, "version: 0x%x\n", version); as->caps.is_spi2 = version > 0x121; as->caps.has_wdrbt = version >= 0x210; +#ifdef CONFIG_SOC_SAM_V4_V5 + /* + * Atmel SoCs based on ARM9 (SAM9x) cores should not use spi_map_buf() + * since this later function tries to map buffers with dma_map_sg() + * even if they have not been allocated inside DMA-safe areas. + * On SoCs based on Cortex A5 (SAMA5Dx), it works anyway because for + * those ARM cores, the data cache follows the PIPT model. + * Also the L2 cache controller of SAMA5D2 uses the PIPT model too. + * In case of PIPT caches, there cannot be cache aliases. + * However on ARM9 cores, the data cache follows the VIVT model, hence + * the cache aliases issue can occur when buffers are allocated from + * DMA-unsafe areas, by vmalloc() for instance, where cache coherency is + * not taken into account or at least not handled completely (cache + * lines of aliases are not invalidated). + * This is not a theorical issue: it was reproduced when trying to mount + * a UBI file-system on a at91sam9g35ek board. + */ + as->caps.has_dma_support = false; +#else as->caps.has_dma_support = version >= 0x212; +#endif + as->caps.has_pdc_support = version < 0x212; } /*-------------------------------------------------------------------------*/ @@ -1567,7 +1588,7 @@ static int atmel_spi_probe(struct platform_device *pdev) } else if (ret == -EPROBE_DEFER) { return ret; } - } else { + } else if (as->caps.has_pdc_support) { as->use_pdc = true; } @@ -1609,8 +1630,9 @@ static int atmel_spi_probe(struct platform_device *pdev) goto out_free_dma; /* go! */ - dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n", - (unsigned long)regs->start, irq); + dev_info(&pdev->dev, "Atmel SPI Controller version 0x%x at 0x%08lx (irq %d)\n", + atmel_get_version(as), (unsigned long)regs->start, + irq); return 0; |