Re: [PATCH v3 0/5] [SCSI] ufshcd: UFS Host Controller Driver

From: James Bottomley
Date: Thu Mar 22 2012 - 09:51:55 EST


On Wed, 2012-02-29 at 12:11 +0530, Santosh Y wrote:
> From: Santosh Yaraganavi <santoshsy@xxxxxxxxx>
>
> UFS:
> Universal Flash Storage is a storage specification for flash devices.
> It is aimed to provide a universal storage interface for both
> embedded and removable flash memory based storage in mobile
> devices such as smart phones and tablet computers. The specification
> is defined by JEDEC Solid State Technology Association. UFS is based
> on MIPI M-PHY physical layer standard. UFS uses MIPI M-PHY as the
> physical layer and MIPI Unipro as the link layer.

This doesn't compile correctly on a 32 bit platform:

CC [M] drivers/scsi/ufs/ufshcd.o
drivers/scsi/ufs/ufshcd.c: In function âufshcd_map_sgâ:
drivers/scsi/ufs/ufshcd.c:555:5: warning: right shift count >= width of
type [enabled by default]
drivers/scsi/ufs/ufshcd.c: In function âufshcd_host_memory_configureâ:
drivers/scsi/ufs/ufshcd.c:831:5: warning: right shift count >= width of
type [enabled by default]
drivers/scsi/ufs/ufshcd.c: In function âufshcd_initialize_hbaâ:
drivers/scsi/ufs/ufshcd.c:1037:2: warning: right shift count >= width of
type [enabled by default]
drivers/scsi/ufs/ufshcd.c:1041:2: warning: right shift count >= width of
type [enabled by default]

That's because you use >> 32 for the upper address bits.

I did the replacement below to use macros which do this correctly
(basically trick the compiler).

James

---

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 07ec973..52b96e8 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -550,9 +550,9 @@ static int ufshcd_map_sg(struct ufshcd_lrb *lrbp)
prd_table[i].size =
cpu_to_le32(((u32) sg_dma_len(sg))-1);
prd_table[i].base_addr =
- cpu_to_le32(sg->dma_address);
+ cpu_to_le32(lower_32_bits(sg->dma_address));
prd_table[i].upper_addr =
- cpu_to_le32((sg->dma_address >> 32));
+ cpu_to_le32(upper_32_bits(sg->dma_address));
}
} else {
lrbp->utr_descriptor_ptr->prd_table_length = 0;
@@ -826,9 +826,9 @@ static void ufshcd_host_memory_configure(struct ufs_hba *hba)
cmd_desc_element_addr =
(cmd_desc_dma_addr + (cmd_desc_size * i));
utrdlp[i].command_desc_base_addr_lo =
- cpu_to_le32(cmd_desc_element_addr);
+ cpu_to_le32(lower_32_bits(cmd_desc_element_addr));
utrdlp[i].command_desc_base_addr_hi =
- cpu_to_le32(cmd_desc_element_addr >> 32);
+ cpu_to_le32(upper_32_bits(cmd_desc_element_addr));

/* Response upiu and prdt offset should be in double words */
utrdlp[i].response_upiu_offset =
@@ -1034,11 +1034,11 @@ static int ufshcd_initialize_hba(struct ufs_hba *hba)
/* Configure UTRL and UTMRL base address registers */
writel(hba->utrdl_dma_addr,
(hba->mmio_base + REG_UTP_TRANSFER_REQ_LIST_BASE_L));
- writel((hba->utrdl_dma_addr >> 32),
+ writel(lower_32_bits(hba->utrdl_dma_addr),
(hba->mmio_base + REG_UTP_TRANSFER_REQ_LIST_BASE_H));
writel(hba->utmrdl_dma_addr,
(hba->mmio_base + REG_UTP_TASK_REQ_LIST_BASE_L));
- writel((hba->utmrdl_dma_addr >> 32),
+ writel(upper_32_bits(hba->utmrdl_dma_addr),
(hba->mmio_base + REG_UTP_TASK_REQ_LIST_BASE_H));

/* Initialize unipro link startup procedure */


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