[PATCH v2 08/12] mtd: nand: denali: clean up comments
Masahiro Yamada
yamada.masahiro at socionext.com
Thu Sep 21 20:46:45 PDT 2017
This driver explains too much about what is apparent from the code.
Comments around basic APIs such as init_completion(), spin_lock_init(),
etc. seem unneeded lessons to kernel developers.
(With those comments dropped, denali_drv_init() is small enough,
so it has been merged into the probe function.)
Also, NAND driver developers should know the NAND init procedure, so
there is no need to explain nand_scan_ident/tail.
I removed FSF's address from the license blocks, and added simple
comments to struct members.
Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com>
---
Changes in v2:
- Add more comments to struct members
drivers/mtd/nand/denali.c | 52 +++++--------------------------------------
drivers/mtd/nand/denali.h | 24 +++++++-------------
drivers/mtd/nand/denali_dt.c | 1 -
drivers/mtd/nand/denali_pci.c | 2 --
4 files changed, 13 insertions(+), 66 deletions(-)
diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c
index ca98015..02ce310 100644
--- a/drivers/mtd/nand/denali.c
+++ b/drivers/mtd/nand/denali.c
@@ -10,11 +10,6 @@
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
- *
- * You should have received a copy of the GNU General Public License along with
- * this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
- *
*/
#include <linux/bitfield.h>
@@ -64,10 +59,6 @@ MODULE_LICENSE("GPL");
*/
#define DENALI_CLK_X_MULT 6
-/*
- * this macro allows us to convert from an MTD structure to our own
- * device context (denali) structure.
- */
static inline struct denali_nand_info *mtd_to_denali(struct mtd_info *mtd)
{
return container_of(mtd_to_nand(mtd), struct denali_nand_info, nand);
@@ -450,9 +441,8 @@ static int denali_sw_ecc_fixup(struct mtd_info *mtd,
} while (!(err_cor_info & ERR_CORRECTION_INFO__LAST_ERR));
/*
- * Once handle all ecc errors, controller will trigger a
- * ECC_TRANSACTION_DONE interrupt, so here just wait for
- * a while for this interrupt
+ * Once handle all ECC errors, controller will trigger an
+ * ECC_TRANSACTION_DONE interrupt.
*/
irq_status = denali_wait_for_irq(denali, INTR__ECC_TRANSACTION_DONE);
if (!(irq_status & INTR__ECC_TRANSACTION_DONE))
@@ -613,7 +603,6 @@ static int denali_dma_xfer(struct denali_nand_info *denali, void *buf,
denali_reset_irq(denali);
denali_setup_dma(denali, dma_addr, page, write);
- /* wait for operation to complete */
irq_status = denali_wait_for_irq(denali, irq_mask);
if (!(irq_status & INTR__DMA_CMD_COMP))
ret = -EIO;
@@ -1185,22 +1174,6 @@ static const struct mtd_ooblayout_ops denali_ooblayout_ops = {
.free = denali_ooblayout_free,
};
-/* initialize driver data structures */
-static void denali_drv_init(struct denali_nand_info *denali)
-{
- /*
- * the completion object will be used to notify
- * the callee that the interrupt is done
- */
- init_completion(&denali->complete);
-
- /*
- * the spinlock will be used to synchronize the ISR with any
- * element that might be access shared data (interrupt status)
- */
- spin_lock_init(&denali->irq_lock);
-}
-
static int denali_multidev_fixup(struct denali_nand_info *denali)
{
struct nand_chip *chip = &denali->nand;
@@ -1260,11 +1233,12 @@ int denali_init(struct denali_nand_info *denali)
mtd->dev.parent = denali->dev;
denali_hw_init(denali);
- denali_drv_init(denali);
+
+ init_completion(&denali->complete);
+ spin_lock_init(&denali->irq_lock);
denali_clear_irq_all(denali);
- /* Request IRQ after all the hardware initialization is finished */
ret = devm_request_irq(denali->dev, denali->irq, denali_isr,
IRQF_SHARED, DENALI_NAND_NAME, denali);
if (ret) {
@@ -1282,7 +1256,6 @@ int denali_init(struct denali_nand_info *denali)
if (!mtd->name)
mtd->name = "denali-nand";
- /* register the driver with the NAND core subsystem */
chip->select_chip = denali_select_chip;
chip->read_byte = denali_read_byte;
chip->write_byte = denali_write_byte;
@@ -1295,11 +1268,6 @@ int denali_init(struct denali_nand_info *denali)
if (denali->clk_x_rate)
chip->setup_data_interface = denali_setup_data_interface;
- /*
- * scan for NAND devices attached to the controller
- * this is the first stage in a two step process to register
- * with the nand subsystem
- */
ret = nand_scan_ident(mtd, denali->max_banks, NULL);
if (ret)
goto disable_irq;
@@ -1323,18 +1291,9 @@ int denali_init(struct denali_nand_info *denali)
chip->buf_align = 16;
}
- /*
- * second stage of the NAND scan
- * this stage requires information regarding ECC and
- * bad block management.
- */
-
chip->bbt_options |= NAND_BBT_USE_FLASH;
chip->bbt_options |= NAND_BBT_NO_OOB;
-
chip->ecc.mode = NAND_ECC_HW_SYNDROME;
-
- /* no subpage writes on denali */
chip->options |= NAND_NO_SUBPAGE_WRITE;
ret = denali_ecc_setup(mtd, chip, denali);
@@ -1418,7 +1377,6 @@ int denali_init(struct denali_nand_info *denali)
}
EXPORT_SYMBOL(denali_init);
-/* driver exit point */
void denali_remove(struct denali_nand_info *denali)
{
struct mtd_info *mtd = nand_to_mtd(&denali->nand);
diff --git a/drivers/mtd/nand/denali.h b/drivers/mtd/nand/denali.h
index 73aad3a..f55ee10 100644
--- a/drivers/mtd/nand/denali.h
+++ b/drivers/mtd/nand/denali.h
@@ -10,11 +10,6 @@
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
- *
- * You should have received a copy of the GNU General Public License along with
- * this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
- *
*/
#ifndef __DENALI_H__
@@ -310,22 +305,19 @@ struct denali_nand_info {
struct device *dev;
void __iomem *reg; /* Register Interface */
void __iomem *host; /* Host Data/Command Interface */
-
- /* elements used by ISR */
struct completion complete;
- spinlock_t irq_lock;
- uint32_t irq_mask;
- uint32_t irq_status;
+ spinlock_t irq_lock; /* protect irq_mask and irq_status */
+ u32 irq_mask; /* interrupts we are waiting for */
+ u32 irq_status; /* interrupts that have happened */
int irq;
-
- void *buf;
+ void *buf; /* for syndrome layout conversion */
dma_addr_t dma_addr;
- int dma_avail;
+ int dma_avail; /* can support DMA? */
int devs_per_cs; /* devices connected in parallel */
- int oob_skip_bytes;
+ int oob_skip_bytes; /* number of bytes reserved for BBM */
int max_banks;
- unsigned int revision;
- unsigned int caps;
+ unsigned int revision; /* IP revision */
+ unsigned int caps; /* IP capability (or quirk) */
const struct nand_ecc_caps *ecc_caps;
};
diff --git a/drivers/mtd/nand/denali_dt.c b/drivers/mtd/nand/denali_dt.c
index 01e0100..cfd33e6 100644
--- a/drivers/mtd/nand/denali_dt.c
+++ b/drivers/mtd/nand/denali_dt.c
@@ -156,7 +156,6 @@ static struct platform_driver denali_dt_driver = {
.of_match_table = denali_nand_dt_ids,
},
};
-
module_platform_driver(denali_dt_driver);
MODULE_LICENSE("GPL");
diff --git a/drivers/mtd/nand/denali_pci.c b/drivers/mtd/nand/denali_pci.c
index 7d5600b..57fb7ae 100644
--- a/drivers/mtd/nand/denali_pci.c
+++ b/drivers/mtd/nand/denali_pci.c
@@ -109,7 +109,6 @@ static int denali_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
return ret;
}
-/* driver exit point */
static void denali_pci_remove(struct pci_dev *dev)
{
struct denali_nand_info *denali = pci_get_drvdata(dev);
@@ -125,5 +124,4 @@ static struct pci_driver denali_pci_driver = {
.probe = denali_pci_probe,
.remove = denali_pci_remove,
};
-
module_pci_driver(denali_pci_driver);
--
2.7.4
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