[PATCH v6 02/18] mtd: nand: denali: remove unneeded find_valid_banks()

[Masahiro Yamada]

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 
---

Changes in v6: None
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 7133a33b4ad3..122df4c6126d 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, [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

[PATCH v6 02/18] mtd: nand: denali: remove unneeded find_valid_banks()

[Masahiro Yamada]

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 
---

Changes in v6: None
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 7133a33b4ad3..122df4c6126d 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, [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