[PATCH v5 08/23] mtd: nand: denali: remove unneeded find_valid_banks()

Masahiro Yamada
2017-06-07T11:53:44Z

The function find_valid_banks() issues the Read ID (0x90) command,
then compares the first byte (Manufacturer ID) of each bank with
the one of bank0.

This is equivalent to what nand_scan_ident() does. The number of
chips is detected there, so this is unneeded.

What is worse for find_valid_banks() is that, if multiple chips are
connected to INTEL_CE4100 platform, it crashes the kernel by BUG().
This is what we should avoid. This function is just harmful and
unneeded.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

Changes in v5: None
Changes in v4: None
Changes in v3: None
Changes in v2:
- Newly added

drivers/mtd/nand/denali.c | 47 -----------------------------------------------
drivers/mtd/nand/denali.h | 1 -
2 files changed, 48 deletions(-)

diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c
index 22acfc34b546..f090486cab66 100644
--- a/drivers/mtd/nand/denali.c
+++ b/drivers/mtd/nand/denali.c
@@ -338,51 +338,6 @@ static void get_samsung_nand_para(struct denali_nand_info *denali,
}

/*
- * determines how many NAND chips are connected to the controller. Note for
- * Intel CE4100 devices we don't support more than one device.
- */
-static void find_valid_banks(struct denali_nand_info *denali)
-{
- uint32_t id[denali->max_banks];
- int i;
-
- denali->total_used_banks = 1;
- for (i = 0; i < denali->max_banks; i++) {
- index_addr(denali, MODE_11 | (i << 24) | 0, 0x90);
- index_addr(denali, MODE_11 | (i << 24) | 1, 0);
- index_addr_read_data(denali, MODE_11 | (i << 24) | 2, &id[i]);
-
- dev_dbg(denali->dev,
- "Return 1st ID for bank[%d]: %x\n", i, id[i]);
-
- if (i == 0) {
- if (!(id[i] & 0x0ff))
- break; /* WTF? */
- } else {
- if ((id[i] & 0x0ff) == (id[0] & 0x0ff))
- denali->total_used_banks++;
- else
- break;
- }
- }
-
- if (denali->platform == INTEL_CE4100) {
- /*
- * Platform limitations of the CE4100 device limit
- * users to a single chip solution for NAND.
- * Multichip support is not enabled.
- */
- if (denali->total_used_banks != 1) {
- dev_err(denali->dev,
- "Sorry, Intel CE4100 only supports a single NAND device.\n");
- BUG();
- }
- }
- dev_dbg(denali->dev,
- "denali->total_used_banks: %d\n", denali->total_used_banks);
-}
-
-/*
* Use the configuration feature register to determine the maximum number of
* banks that the hardware supports.
*/
@@ -439,8 +394,6 @@ static uint16_t denali_nand_timing_set(struct denali_nand_info *denali)
ioread32(denali->flash_reg + RDWR_EN_HI_CNT),
ioread32(denali->flash_reg + CS_SETUP_CNT));

- find_valid_banks(denali);
-
/*
* If the user specified to override the default timings
* with a specific ONFI mode, we apply those changes here.
diff --git a/drivers/mtd/nand/denali.h b/drivers/mtd/nand/denali.h
index 352d8328b94a..0e4a8965f6f1 100644
--- a/drivers/mtd/nand/denali.h
+++ b/drivers/mtd/nand/denali.h
@@ -326,7 +326,6 @@ struct denali_nand_info {
int platform;
struct nand_buf buf;
struct device *dev;
- int total_used_banks;
int page;
void __iomem *flash_reg; /* Register Interface */
void __iomem *flash_mem; /* Host Data/Command Interface */
--
2.7.4