11399346ac
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20200507190033.GA15215@embeddedor
93 lines
2.5 KiB
C
93 lines
2.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_MTD_QINFO_H
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#define __LINUX_MTD_QINFO_H
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#include <linux/mtd/map.h>
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#include <linux/wait.h>
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#include <linux/spinlock.h>
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#include <linux/delay.h>
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#include <linux/mtd/mtd.h>
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#include <linux/mtd/flashchip.h>
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#include <linux/mtd/partitions.h>
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/* lpddr_private describes lpddr flash chip in memory map
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* @ManufactId - Chip Manufacture ID
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* @DevId - Chip Device ID
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* @qinfo - pointer to qinfo records describing the chip
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* @numchips - number of chips including virual RWW partitions
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* @chipshift - Chip/partition size 2^chipshift
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* @chips - per-chip data structure
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*/
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struct lpddr_private {
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uint16_t ManufactId;
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uint16_t DevId;
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struct qinfo_chip *qinfo;
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int numchips;
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unsigned long chipshift;
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struct flchip chips[];
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};
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/* qinfo_query_info structure contains request information for
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* each qinfo record
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* @major - major number of qinfo record
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* @major - minor number of qinfo record
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* @id_str - descriptive string to access the record
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* @desc - detailed description for the qinfo record
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*/
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struct qinfo_query_info {
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uint8_t major;
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uint8_t minor;
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char *id_str;
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char *desc;
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};
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/*
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* qinfo_chip structure contains necessary qinfo records data
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* @DevSizeShift - Device size 2^n bytes
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* @BufSizeShift - Program buffer size 2^n bytes
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* @TotalBlocksNum - Total number of blocks
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* @UniformBlockSizeShift - Uniform block size 2^UniformBlockSizeShift bytes
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* @HWPartsNum - Number of hardware partitions
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* @SuspEraseSupp - Suspend erase supported
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* @SingleWordProgTime - Single word program 2^SingleWordProgTime u-sec
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* @ProgBufferTime - Program buffer write 2^ProgBufferTime u-sec
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* @BlockEraseTime - Block erase 2^BlockEraseTime m-sec
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*/
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struct qinfo_chip {
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/* General device info */
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uint16_t DevSizeShift;
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uint16_t BufSizeShift;
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/* Erase block information */
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uint16_t TotalBlocksNum;
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uint16_t UniformBlockSizeShift;
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/* Partition information */
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uint16_t HWPartsNum;
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/* Optional features */
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uint16_t SuspEraseSupp;
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/* Operation typical time */
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uint16_t SingleWordProgTime;
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uint16_t ProgBufferTime;
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uint16_t BlockEraseTime;
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};
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/* defines for fixup usage */
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#define LPDDR_MFR_ANY 0xffff
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#define LPDDR_ID_ANY 0xffff
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#define NUMONYX_MFGR_ID 0x0089
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#define R18_DEVICE_ID_1G 0x893c
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static inline map_word lpddr_build_cmd(u_long cmd, struct map_info *map)
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{
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map_word val = { {0} };
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val.x[0] = cmd;
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return val;
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}
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#define CMD(x) lpddr_build_cmd(x, map)
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#define CMDVAL(cmd) cmd.x[0]
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struct mtd_info *lpddr_cmdset(struct map_info *);
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#endif
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