diff options
author | Pekon Gupta <pekon@ti.com> | 2013-10-24 18:20:21 +0530 |
---|---|---|
committer | Brian Norris <computersforpeace@gmail.com> | 2013-11-06 23:33:09 -0800 |
commit | a919e51161b58ed7e6e663daba99ab7d558808f3 (patch) | |
tree | 3418227e6e03e1c43cea1d6e41a48fcc519307dd /drivers/mtd | |
parent | f18befb57b0779094ac7658fa7be5cf559da835f (diff) |
mtd: nand: omap2: clean-up BCHx_HW and BCHx_SW ECC configurations in device_probe
current implementation in omap3_init_bch() has some redundant code like:
(1) omap3_init_bch() re-probes the DT-binding to detect presence of ELM h/w
engine on SoC. And based on that it selects implemetation of ecc-scheme.
However, this is already done as part of GPMC DT parsing.
(2) As omap3_init_bch() serves as common function for configuring all types of
BCHx ecc-schemes, so there are multiple levels of redudant if..then..else
checks while populating nand_chip->ecc.
This patch make following changes to OMAP NAND driver:
(1) removes omap3_init_bch(): each ecc-scheme is individually configured in
omap_nand_probe() there by removing redundant if..then..else checks.
(2) adds is_elm_present(): re-probing of ELM device via DT is not required as
it's done in GPMC driver probe. Thus is_elm_present() just initializes ELM
driver with NAND probe data, when ecc-scheme with h/w based error-detection
is used.
(3) separates out configuration of different flavours of "BCH4" and "BCH8"
ecc-schemes as given in below table
(4) conditionally compiles callbacks implementations of ecc.hwctl(),
ecc.calculate(), ecc.correct() to avoid warning of un-used functions.
+---------------------------------------+---------------+---------------+
| ECC scheme |ECC calculation|Error detection|
+---------------------------------------+---------------+---------------+
|OMAP_ECC_HAM1_CODE_HW |H/W (GPMC) |S/W |
+---------------------------------------+---------------+---------------+
|OMAP_ECC_BCH4_CODE_HW_DETECTION_SW |H/W (GPMC) |S/W (lib/bch.c)|
| (needs CONFIG_MTD_NAND_ECC_BCH) | | |
| | | |
|OMAP_ECC_BCH4_CODE_HW |H/W (GPMC) |H/W (ELM) |
| (needs CONFIG_MTD_NAND_OMAP_BCH && | | |
| ti,elm-id) | | |
+---------------------------------------+---------------+---------------+
|OMAP_ECC_BCH8_CODE_HW_DETECTION_SW |H/W (GPMC) |S/W (lib/bch.c)|
| (needs CONFIG_MTD_NAND_ECC_BCH) | | |
| | | |
|OMAP_ECC_BCH8_CODE_HW |H/W (GPMC) |H/W (ELM) |
| (needs CONFIG_MTD_NAND_OMAP_BCH && | | |
| ti,elm-id) | | |
+---------------------------------------+---------------+---------------+
- 'CONFIG_MTD_NAND_ECC_BCH' is generic KConfig required to build lib/bch.c
which is required for ECC error detection done in software.
(mainly used for legacy platforms which do not have on-chip ELM engine)
- 'CONFIG_MTD_NAND_OMAP_BCH' is OMAP specific Kconfig to detemine presence
on ELM h/w engine on SoC.
Signed-off-by: Pekon Gupta <pekon@ti.com>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Diffstat (limited to 'drivers/mtd')
-rw-r--r-- | drivers/mtd/nand/omap2.c | 281 |
1 files changed, 158 insertions, 123 deletions
diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c index f464321c598d..86ce48b2c47a 100644 --- a/drivers/mtd/nand/omap2.c +++ b/drivers/mtd/nand/omap2.c @@ -25,10 +25,8 @@ #include <linux/of.h> #include <linux/of_device.h> -#ifdef CONFIG_MTD_NAND_OMAP_BCH #include <linux/bch.h> #include <linux/platform_data/elm.h> -#endif #include <linux/platform_data/mtd-nand-omap2.h> @@ -141,6 +139,8 @@ #define BCH_ECC_SIZE0 0x0 /* ecc_size0 = 0, no oob protection */ #define BCH_ECC_SIZE1 0x20 /* ecc_size1 = 32 */ +#define OMAP_ECC_BCH8_POLYNOMIAL 0x201b + #ifdef CONFIG_MTD_NAND_OMAP_BCH static u_char bch8_vector[] = {0xf3, 0xdb, 0x14, 0x16, 0x8b, 0xd2, 0xbe, 0xcc, 0xac, 0x6b, 0xff, 0x99, 0x7b}; @@ -182,14 +182,12 @@ struct omap_nand_info { u_char *buf; int buf_len; struct gpmc_nand_regs reg; - -#ifdef CONFIG_MTD_NAND_OMAP_BCH + /* fields specific for BCHx_HW ECC scheme */ struct bch_control *bch; struct nand_ecclayout ecclayout; bool is_elm_used; struct device *elm_dev; struct device_node *of_node; -#endif }; /** @@ -1058,8 +1056,7 @@ static int omap_dev_ready(struct mtd_info *mtd) } } -#ifdef CONFIG_MTD_NAND_OMAP_BCH - +#if defined(CONFIG_MTD_NAND_ECC_BCH) || defined(CONFIG_MTD_NAND_OMAP_BCH) /** * omap3_enable_hwecc_bch - Program OMAP3 GPMC to perform BCH ECC correction * @mtd: MTD device structure @@ -1140,7 +1137,9 @@ static void omap3_enable_hwecc_bch(struct mtd_info *mtd, int mode) /* Clear ecc and enable bits */ writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control); } +#endif +#ifdef CONFIG_MTD_NAND_ECC_BCH /** * omap3_calculate_ecc_bch4 - Generate 7 bytes of ECC bytes * @mtd: MTD device structure @@ -1225,7 +1224,9 @@ static int omap3_calculate_ecc_bch8(struct mtd_info *mtd, const u_char *dat, return 0; } +#endif /* CONFIG_MTD_NAND_ECC_BCH */ +#ifdef CONFIG_MTD_NAND_OMAP_BCH /** * omap3_calculate_ecc_bch - Generate bytes of ECC bytes * @mtd: MTD device structure @@ -1517,7 +1518,9 @@ static int omap_elm_correct_data(struct mtd_info *mtd, u_char *data, return stat; } +#endif /* CONFIG_MTD_NAND_OMAP_BCH */ +#ifdef CONFIG_MTD_NAND_ECC_BCH /** * omap3_correct_data_bch - Decode received data and correct errors * @mtd: MTD device structure @@ -1549,7 +1552,9 @@ static int omap3_correct_data_bch(struct mtd_info *mtd, u_char *data, } return count; } +#endif /* CONFIG_MTD_NAND_ECC_BCH */ +#ifdef CONFIG_MTD_NAND_OMAP_BCH /** * omap_write_page_bch - BCH ecc based write page function for entire page * @mtd: mtd info structure @@ -1637,118 +1642,48 @@ static int omap_read_page_bch(struct mtd_info *mtd, struct nand_chip *chip, } /** - * omap3_free_bch - Release BCH ecc resources - * @mtd: MTD device structure + * is_elm_present - checks for presence of ELM module by scanning DT nodes + * @omap_nand_info: NAND device structure containing platform data + * @bch_type: 0x0=BCH4, 0x1=BCH8, 0x2=BCH16 */ -static void omap3_free_bch(struct mtd_info *mtd) +static int is_elm_present(struct omap_nand_info *info, + struct device_node *elm_node, enum bch_ecc bch_type) { - struct omap_nand_info *info = container_of(mtd, struct omap_nand_info, - mtd); - if (info->bch) { - free_bch(info->bch); - info->bch = NULL; + struct platform_device *pdev; + info->is_elm_used = false; + /* check whether elm-id is passed via DT */ + if (!elm_node) { + pr_err("nand: error: ELM DT node not found\n"); + return -ENODEV; + } + pdev = of_find_device_by_node(elm_node); + /* check whether ELM device is registered */ + if (!pdev) { + pr_err("nand: error: ELM device not found\n"); + return -ENODEV; } + /* ELM module available, now configure it */ + info->elm_dev = &pdev->dev; + if (elm_config(info->elm_dev, bch_type)) + return -ENODEV; + info->is_elm_used = true; + return 0; } +#endif /* CONFIG_MTD_NAND_ECC_BCH */ +#ifdef CONFIG_MTD_NAND_ECC_BCH /** - * omap3_init_bch - Initialize BCH ECC + * omap3_free_bch - Release BCH ecc resources * @mtd: MTD device structure - * @ecc_opt: OMAP ECC mode (OMAP_ECC_BCH4_CODE_HW or OMAP_ECC_BCH8_CODE_HW) */ -static int omap3_init_bch(struct mtd_info *mtd, int ecc_opt) +static void omap3_free_bch(struct mtd_info *mtd) { - int max_errors; struct omap_nand_info *info = container_of(mtd, struct omap_nand_info, mtd); -#ifdef CONFIG_MTD_NAND_OMAP_BCH8 - const int hw_errors = BCH8_MAX_ERROR; -#else - const int hw_errors = BCH4_MAX_ERROR; -#endif - enum bch_ecc bch_type; - const __be32 *parp; - int lenp; - struct device_node *elm_node; - - info->bch = NULL; - - max_errors = (ecc_opt == OMAP_ECC_BCH8_CODE_HW) ? - BCH8_MAX_ERROR : BCH4_MAX_ERROR; - if (max_errors != hw_errors) { - pr_err("cannot configure %d-bit BCH ecc, only %d-bit supported", - max_errors, hw_errors); - goto fail; - } - - info->nand.ecc.size = 512; - info->nand.ecc.hwctl = omap3_enable_hwecc_bch; - info->nand.ecc.mode = NAND_ECC_HW; - info->nand.ecc.strength = max_errors; - - if (hw_errors == BCH8_MAX_ERROR) - bch_type = BCH8_ECC; - else - bch_type = BCH4_ECC; - - /* Detect availability of ELM module */ - parp = of_get_property(info->of_node, "elm_id", &lenp); - if ((parp == NULL) && (lenp != (sizeof(void *) * 2))) { - pr_err("Missing elm_id property, fall back to Software BCH\n"); - info->is_elm_used = false; - } else { - struct platform_device *pdev; - - elm_node = of_find_node_by_phandle(be32_to_cpup(parp)); - pdev = of_find_device_by_node(elm_node); - info->elm_dev = &pdev->dev; - - if (elm_config(info->elm_dev, bch_type) == 0) - info->is_elm_used = true; - } - - if (info->is_elm_used && (mtd->writesize <= 4096)) { - - if (hw_errors == BCH8_MAX_ERROR) - info->nand.ecc.bytes = BCH8_SIZE; - else - info->nand.ecc.bytes = BCH4_SIZE; - - info->nand.ecc.correct = omap_elm_correct_data; - info->nand.ecc.calculate = omap3_calculate_ecc_bch; - info->nand.ecc.read_page = omap_read_page_bch; - info->nand.ecc.write_page = omap_write_page_bch; - } else { - /* - * software bch library is only used to detect and - * locate errors - */ - info->bch = init_bch(13, max_errors, - 0x201b /* hw polynomial */); - if (!info->bch) - goto fail; - - info->nand.ecc.correct = omap3_correct_data_bch; - - /* - * The number of corrected errors in an ecc block that will - * trigger block scrubbing defaults to the ecc strength (4 or 8) - * Set mtd->bitflip_threshold here to define a custom threshold. - */ - - if (max_errors == 8) { - info->nand.ecc.bytes = 13; - info->nand.ecc.calculate = omap3_calculate_ecc_bch8; - } else { - info->nand.ecc.bytes = 7; - info->nand.ecc.calculate = omap3_calculate_ecc_bch4; - } + if (info->bch) { + free_bch(info->bch); + info->bch = NULL; } - - pr_info("enabling NAND BCH ecc with %d-bit correction\n", max_errors); - return 0; -fail: - omap3_free_bch(mtd); - return -1; } /** @@ -1806,11 +1741,6 @@ fail: } #else -static int omap3_init_bch(struct mtd_info *mtd, int ecc_opt) -{ - pr_err("CONFIG_MTD_NAND_OMAP_BCH is not enabled\n"); - return -1; -} static int omap3_init_bch_tail(struct mtd_info *mtd) { return -1; @@ -1818,7 +1748,7 @@ static int omap3_init_bch_tail(struct mtd_info *mtd) static void omap3_free_bch(struct mtd_info *mtd) { } -#endif /* CONFIG_MTD_NAND_OMAP_BCH */ +#endif /* CONFIG_MTD_NAND_ECC_BCH */ static int omap_nand_probe(struct platform_device *pdev) { @@ -1851,15 +1781,14 @@ static int omap_nand_probe(struct platform_device *pdev) info->pdev = pdev; info->gpmc_cs = pdata->cs; info->reg = pdata->reg; + info->bch = NULL; + info->of_node = pdata->of_node; mtd = &info->mtd; mtd->priv = &info->nand; mtd->name = dev_name(&pdev->dev); mtd->owner = THIS_MODULE; nand_chip = &info->nand; nand_chip->options |= NAND_SKIP_BBTSCAN; -#ifdef CONFIG_MTD_NAND_OMAP_BCH - info->of_node = pdata->of_node; -#endif res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (res == NULL) { @@ -2001,22 +1930,125 @@ static int omap_nand_probe(struct platform_device *pdev) goto out_release_mem_region; } - /* select the ecc type */ - if (pdata->ecc_opt == OMAP_ECC_HAM1_CODE_HW) { + /* populate MTD interface based on ECC scheme */ + switch (pdata->ecc_opt) { + case OMAP_ECC_HAM1_CODE_HW: + pr_info("nand: using OMAP_ECC_HAM1_CODE_HW\n"); + nand_chip->ecc.mode = NAND_ECC_HW; nand_chip->ecc.bytes = 3; nand_chip->ecc.size = 512; nand_chip->ecc.strength = 1; nand_chip->ecc.calculate = omap_calculate_ecc; nand_chip->ecc.hwctl = omap_enable_hwecc; nand_chip->ecc.correct = omap_correct_data; - nand_chip->ecc.mode = NAND_ECC_HW; - } else if ((pdata->ecc_opt == OMAP_ECC_BCH4_CODE_HW) || - (pdata->ecc_opt == OMAP_ECC_BCH8_CODE_HW)) { - err = omap3_init_bch(mtd, pdata->ecc_opt); - if (err) { + break; + + case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW: +#ifdef CONFIG_MTD_NAND_ECC_BCH + pr_info("nand: using OMAP_ECC_BCH4_CODE_HW_DETECTION_SW\n"); + nand_chip->ecc.mode = NAND_ECC_HW; + nand_chip->ecc.size = 512; + nand_chip->ecc.bytes = 7; + nand_chip->ecc.strength = 4; + nand_chip->ecc.hwctl = omap3_enable_hwecc_bch; + nand_chip->ecc.correct = omap3_correct_data_bch; + nand_chip->ecc.calculate = omap3_calculate_ecc_bch4; + /* software bch library is used for locating errors */ + info->bch = init_bch(nand_chip->ecc.bytes, + nand_chip->ecc.strength, + OMAP_ECC_BCH8_POLYNOMIAL); + if (!info->bch) { + pr_err("nand: error: unable to use s/w BCH library\n"); err = -EINVAL; + } + break; +#else + pr_err("nand: error: CONFIG_MTD_NAND_ECC_BCH not enabled\n"); + err = -EINVAL; + goto out_release_mem_region; +#endif + + case OMAP_ECC_BCH4_CODE_HW: +#ifdef CONFIG_MTD_NAND_OMAP_BCH + pr_info("nand: using OMAP_ECC_BCH4_CODE_HW ECC scheme\n"); + nand_chip->ecc.mode = NAND_ECC_HW; + nand_chip->ecc.size = 512; + /* 14th bit is kept reserved for ROM-code compatibility */ + nand_chip->ecc.bytes = 7 + 1; + nand_chip->ecc.strength = 4; + nand_chip->ecc.hwctl = omap3_enable_hwecc_bch; + nand_chip->ecc.correct = omap_elm_correct_data; + nand_chip->ecc.calculate = omap3_calculate_ecc_bch; + nand_chip->ecc.read_page = omap_read_page_bch; + nand_chip->ecc.write_page = omap_write_page_bch; + /* This ECC scheme requires ELM H/W block */ + if (is_elm_present(info, pdata->elm_of_node, BCH4_ECC) < 0) { + pr_err("nand: error: could not initialize ELM\n"); + err = -ENODEV; goto out_release_mem_region; } + break; +#else + pr_err("nand: error: CONFIG_MTD_NAND_OMAP_BCH not enabled\n"); + err = -EINVAL; + goto out_release_mem_region; +#endif + + case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW: +#ifdef CONFIG_MTD_NAND_ECC_BCH + pr_info("nand: using OMAP_ECC_BCH8_CODE_HW_DETECTION_SW\n"); + nand_chip->ecc.mode = NAND_ECC_HW; + nand_chip->ecc.size = 512; + nand_chip->ecc.bytes = 13; + nand_chip->ecc.strength = 8; + nand_chip->ecc.hwctl = omap3_enable_hwecc_bch; + nand_chip->ecc.correct = omap3_correct_data_bch; + nand_chip->ecc.calculate = omap3_calculate_ecc_bch8; + /* software bch library is used for locating errors */ + info->bch = init_bch(nand_chip->ecc.bytes, + nand_chip->ecc.strength, + OMAP_ECC_BCH8_POLYNOMIAL); + if (!info->bch) { + pr_err("nand: error: unable to use s/w BCH library\n"); + err = -EINVAL; + goto out_release_mem_region; + } + break; +#else + pr_err("nand: error: CONFIG_MTD_NAND_ECC_BCH not enabled\n"); + err = -EINVAL; + goto out_release_mem_region; +#endif + + case OMAP_ECC_BCH8_CODE_HW: +#ifdef CONFIG_MTD_NAND_OMAP_BCH + pr_info("nand: using OMAP_ECC_BCH8_CODE_HW ECC scheme\n"); + nand_chip->ecc.mode = NAND_ECC_HW; + nand_chip->ecc.size = 512; + /* 14th bit is kept reserved for ROM-code compatibility */ + nand_chip->ecc.bytes = 13 + 1; + nand_chip->ecc.strength = 8; + nand_chip->ecc.hwctl = omap3_enable_hwecc_bch; + nand_chip->ecc.correct = omap_elm_correct_data; + nand_chip->ecc.calculate = omap3_calculate_ecc_bch; + nand_chip->ecc.read_page = omap_read_page_bch; + nand_chip->ecc.write_page = omap_write_page_bch; + /* This ECC scheme requires ELM H/W block */ + if (is_elm_present(info, pdata->elm_of_node, BCH8_ECC) < 0) { + pr_err("nand: error: could not initialize ELM\n"); + goto out_release_mem_region; + } + break; +#else + pr_err("nand: error: CONFIG_MTD_NAND_OMAP_BCH not enabled\n"); + err = -EINVAL; + goto out_release_mem_region; +#endif + + default: + pr_err("nand: error: invalid or unsupported ECC scheme\n"); + err = -EINVAL; + goto out_release_mem_region; } /* rom code layout */ @@ -2038,6 +2070,8 @@ static int omap_nand_probe(struct platform_device *pdev) nand_chip->ecc.layout = &omap_oobinfo; } else if ((pdata->ecc_opt == OMAP_ECC_BCH4_CODE_HW) || + (pdata->ecc_opt == OMAP_ECC_BCH4_CODE_HW_DETECTION_SW) || + (pdata->ecc_opt == OMAP_ECC_BCH8_CODE_HW_DETECTION_SW) || (pdata->ecc_opt == OMAP_ECC_BCH8_CODE_HW)) { /* build OOB layout for BCH ECC correction */ err = omap3_init_bch_tail(mtd); @@ -2070,6 +2104,7 @@ out_release_mem_region: free_irq(info->gpmc_irq_fifo, info); release_mem_region(info->phys_base, info->mem_size); out_free_info: + omap3_free_bch(mtd); kfree(info); return err; |