Re: [PATCH 11/12] esp: enable CONFIG2_FENAB for am53c974

[Paolo Bonzini <pbonzini@redhat.com>]

On 21/11/2014 13:41, Hannes Reinecke wrote:
> CONFIG2_FENAB ('feature enable') changed definition between chip
> revisions, from 'Latch SCSI Phase' to 'Latch SCSI Phase, display
> chip ID upon reset, and enable 24 bit addresses'.
> So only enable it for am53c974 where we know what it's doing.
> 
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
>  drivers/scsi/am53c974.c | 41 +++++++++++++++++++++++++++++++++++++++++
>  drivers/scsi/esp_scsi.c |  2 ++
>  2 files changed, 43 insertions(+)
> 
> diff --git a/drivers/scsi/am53c974.c b/drivers/scsi/am53c974.c
> index 340cb2f..55622eb 100644
> --- a/drivers/scsi/am53c974.c
> +++ b/drivers/scsi/am53c974.c
> @@ -17,6 +17,8 @@
>  #define DRV_MODULE_NAME "am53c974"
>  #define DRV_MODULE_VERSION "1.00"
>  
> +static bool am53c974_fenab = true;
> +
>  // #define ESP_DMA_DEBUG
>  
>  #define ESP_DMA_CMD 0x10
> @@ -254,6 +256,8 @@ static void pci_esp_send_dma_cmd(struct esp *esp, u32 addr, u32 esp_count,
>  
>  	pci_esp_write8(esp, (esp_count >> 0) & 0xff, ESP_TCLOW);
>  	pci_esp_write8(esp, (esp_count >> 8) & 0xff, ESP_TCMED);
> +	if (esp->config2 & ESP_CONFIG2_FENAB)
> +		pci_esp_write8(esp, (esp_count >> 16) & 0xff, ESP_TCHI);
>  
>  	pci_esp_write32(esp, esp_count, ESP_DMA_STC);
>  	pci_esp_write32(esp, addr, ESP_DMA_SPA);
> @@ -267,6 +271,33 @@ static void pci_esp_send_dma_cmd(struct esp *esp, u32 addr, u32 esp_count,
>  	pci_esp_write8(esp, ESP_DMA_CMD_START | val, ESP_DMA_CMD);
>  }
>  
> +static u32 pci_esp_dma_length_limit(struct esp *esp, u32 dma_addr, u32 dma_len)
> +{
> +	int dma_limit = 16;
> +	u32 base, end;
> +
> +	/*
> +	 * If CONFIG2_FENAB is set we can
> +	 * handle up to 24 bit addresses
> +	 */
> +	if (esp->config2 & ESP_CONFIG2_FENAB)
> +		dma_limit = 24;
> +
> +	if (dma_len > (1U << dma_limit))
> +		dma_len = (1U << dma_limit);
> +
> +	/*
> +	 * Prevent crossing a 24-bit address boundary.
> +	 */
> +	base = dma_addr & ((1U << 24) - 1U);
> +	end = base + dma_len;
> +	if (end > (1U << 24))
> +		end = (1U <<24);
> +	dma_len = end - base;
> +
> +	return dma_len;
> +}
> +
>  static const struct esp_driver_ops pci_esp_ops = {
>  	.esp_write8	=	pci_esp_write8,
>  	.esp_read8	=	pci_esp_read8,
> @@ -280,6 +311,7 @@ static const struct esp_driver_ops pci_esp_ops = {
>  	.dma_invalidate	=	pci_esp_dma_invalidate,
>  	.send_dma_cmd	=	pci_esp_send_dma_cmd,
>  	.dma_error	=	pci_esp_dma_error,
> +	.dma_length_limit =	pci_esp_dma_length_limit,
>  };
>  
>  /*
> @@ -417,6 +449,12 @@ static int pci_esp_probe_one(struct pci_dev *pdev,
>  	 * DMA for command submission.
>  	 */
>  	esp->flags |= ESP_FLAG_USE_FIFO;
> +	/*
> +	 * Enable CONFIG2_FENAB to allow for large DMA transfers
> +	 */
> +	if (am53c974_fenab)
> +		esp->config2 |= ESP_CONFIG2_FENAB;
> +
>  	pep->esp = esp;
>  
>  	if (pci_request_regions(pdev, DRV_MODULE_NAME)) {
> @@ -535,5 +573,8 @@ MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>");
>  MODULE_LICENSE("GPL");
>  MODULE_VERSION(DRV_MODULE_VERSION);
>  
> +module_param(am53c974_fenab, bool, 0444);
> +MODULE_PARM_DESC(am53c974_fenab, "Enable 24-bit DMA transfer sizes");
> +
>  module_init(am53c974_module_init);
>  module_exit(am53c974_module_exit);
> diff --git a/drivers/scsi/esp_scsi.c b/drivers/scsi/esp_scsi.c
> index bd17516..56f361e 100644
> --- a/drivers/scsi/esp_scsi.c
> +++ b/drivers/scsi/esp_scsi.c
> @@ -1343,6 +1343,8 @@ static int esp_data_bytes_sent(struct esp *esp, struct esp_cmd_entry *ent,
>  			  (((unsigned int)esp_read8(ESP_TCMED)) << 8));
>  		if (esp->rev == FASHME)
>  			ecount |= ((unsigned int)esp_read8(FAS_RLO)) << 16;
> +		if (esp->rev == PCSCSI && (esp->config2 & ESP_CONFIG2_FENAB))
> +			ecount |= ((unsigned int)esp_read8(ESP_TCHI)) << 16;
>  	}
>  
>  	bytes_sent = esp->data_dma_len;
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>