From 1dfac31a5a63ac04a9b5fbc3f5105a586560f191 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sat, 23 Jun 2018 01:06:38 +0900 Subject: [PATCH] mtd: rawnand: denali: optimize timing parameters for data interface This commit improves the ->setup_data_interface() hook. The denali_setup_data_interface() needs the frequency of clk_x and the ratio of clk_x / clk. The latter is currently hardcoded in the driver, like this: #define DENALI_CLK_X_MULT 6 The IP datasheet requires that clk_x / clk be 4, 5, or 6. I just chose 6 because it is the most defensive value, but it is not optimal. By getting the clock rate of both "clk" and "clk_x", the driver can compute the timing values more precisely. To not break the existing platforms, the fallback value, 50 MHz is provided. It is true for all upstreamed platforms. Signed-off-by: Masahiro Yamada Reviewed-by: Richard Weinberger Tested-by: Richard Weinberger Signed-off-by: Miquel Raynal --- drivers/mtd/nand/raw/denali.c | 49 +++++++++++++++---------------- drivers/mtd/nand/raw/denali.h | 1 + drivers/mtd/nand/raw/denali_dt.c | 2 ++ drivers/mtd/nand/raw/denali_pci.c | 1 + 4 files changed, 28 insertions(+), 25 deletions(-) diff --git a/drivers/mtd/nand/raw/denali.c b/drivers/mtd/nand/raw/denali.c index a586a1d8b997..4d53f41ada08 100644 --- a/drivers/mtd/nand/raw/denali.c +++ b/drivers/mtd/nand/raw/denali.c @@ -51,14 +51,6 @@ MODULE_LICENSE("GPL"); #define DENALI_INVALID_BANK -1 #define DENALI_NR_BANKS 4 -/* - * The bus interface clock, clk_x, is phase aligned with the core clock. The - * clk_x is an integral multiple N of the core clk. The value N is configured - * at IP delivery time, and its available value is 4, 5, or 6. We need to align - * to the largest value to make it work with any possible configuration. - */ -#define DENALI_CLK_X_MULT 6 - 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); @@ -954,7 +946,7 @@ static int denali_setup_data_interface(struct mtd_info *mtd, int chipnr, { struct denali_nand_info *denali = mtd_to_denali(mtd); const struct nand_sdr_timings *timings; - unsigned long t_clk; + unsigned long t_x, mult_x; int acc_clks, re_2_we, re_2_re, we_2_re, addr_2_data; int rdwr_en_lo, rdwr_en_hi, rdwr_en_lo_hi, cs_setup; int addr_2_data_mask; @@ -965,15 +957,24 @@ static int denali_setup_data_interface(struct mtd_info *mtd, int chipnr, return PTR_ERR(timings); /* clk_x period in picoseconds */ - t_clk = DIV_ROUND_DOWN_ULL(1000000000000ULL, denali->clk_x_rate); - if (!t_clk) + t_x = DIV_ROUND_DOWN_ULL(1000000000000ULL, denali->clk_x_rate); + if (!t_x) + return -EINVAL; + + /* + * The bus interface clock, clk_x, is phase aligned with the core clock. + * The clk_x is an integral multiple N of the core clk. The value N is + * configured at IP delivery time, and its available value is 4, 5, 6. + */ + mult_x = DIV_ROUND_CLOSEST_ULL(denali->clk_x_rate, denali->clk_rate); + if (mult_x < 4 || mult_x > 6) return -EINVAL; if (chipnr == NAND_DATA_IFACE_CHECK_ONLY) return 0; /* tREA -> ACC_CLKS */ - acc_clks = DIV_ROUND_UP(timings->tREA_max, t_clk); + acc_clks = DIV_ROUND_UP(timings->tREA_max, t_x); acc_clks = min_t(int, acc_clks, ACC_CLKS__VALUE); tmp = ioread32(denali->reg + ACC_CLKS); @@ -982,7 +983,7 @@ static int denali_setup_data_interface(struct mtd_info *mtd, int chipnr, iowrite32(tmp, denali->reg + ACC_CLKS); /* tRWH -> RE_2_WE */ - re_2_we = DIV_ROUND_UP(timings->tRHW_min, t_clk); + re_2_we = DIV_ROUND_UP(timings->tRHW_min, t_x); re_2_we = min_t(int, re_2_we, RE_2_WE__VALUE); tmp = ioread32(denali->reg + RE_2_WE); @@ -991,7 +992,7 @@ static int denali_setup_data_interface(struct mtd_info *mtd, int chipnr, iowrite32(tmp, denali->reg + RE_2_WE); /* tRHZ -> RE_2_RE */ - re_2_re = DIV_ROUND_UP(timings->tRHZ_max, t_clk); + re_2_re = DIV_ROUND_UP(timings->tRHZ_max, t_x); re_2_re = min_t(int, re_2_re, RE_2_RE__VALUE); tmp = ioread32(denali->reg + RE_2_RE); @@ -1005,8 +1006,7 @@ static int denali_setup_data_interface(struct mtd_info *mtd, int chipnr, * With WE_2_RE properly set, the Denali controller automatically takes * care of the delay; the driver need not set NAND_WAIT_TCCS. */ - we_2_re = DIV_ROUND_UP(max(timings->tCCS_min, timings->tWHR_min), - t_clk); + we_2_re = DIV_ROUND_UP(max(timings->tCCS_min, timings->tWHR_min), t_x); we_2_re = min_t(int, we_2_re, TWHR2_AND_WE_2_RE__WE_2_RE); tmp = ioread32(denali->reg + TWHR2_AND_WE_2_RE); @@ -1021,7 +1021,7 @@ static int denali_setup_data_interface(struct mtd_info *mtd, int chipnr, if (denali->revision < 0x0501) addr_2_data_mask >>= 1; - addr_2_data = DIV_ROUND_UP(timings->tADL_min, t_clk); + addr_2_data = DIV_ROUND_UP(timings->tADL_min, t_x); addr_2_data = min_t(int, addr_2_data, addr_2_data_mask); tmp = ioread32(denali->reg + TCWAW_AND_ADDR_2_DATA); @@ -1031,7 +1031,7 @@ static int denali_setup_data_interface(struct mtd_info *mtd, int chipnr, /* tREH, tWH -> RDWR_EN_HI_CNT */ rdwr_en_hi = DIV_ROUND_UP(max(timings->tREH_min, timings->tWH_min), - t_clk); + t_x); rdwr_en_hi = min_t(int, rdwr_en_hi, RDWR_EN_HI_CNT__VALUE); tmp = ioread32(denali->reg + RDWR_EN_HI_CNT); @@ -1040,11 +1040,10 @@ static int denali_setup_data_interface(struct mtd_info *mtd, int chipnr, iowrite32(tmp, denali->reg + RDWR_EN_HI_CNT); /* tRP, tWP -> RDWR_EN_LO_CNT */ - rdwr_en_lo = DIV_ROUND_UP(max(timings->tRP_min, timings->tWP_min), - t_clk); + rdwr_en_lo = DIV_ROUND_UP(max(timings->tRP_min, timings->tWP_min), t_x); rdwr_en_lo_hi = DIV_ROUND_UP(max(timings->tRC_min, timings->tWC_min), - t_clk); - rdwr_en_lo_hi = max(rdwr_en_lo_hi, DENALI_CLK_X_MULT); + t_x); + rdwr_en_lo_hi = max_t(int, rdwr_en_lo_hi, mult_x); rdwr_en_lo = max(rdwr_en_lo, rdwr_en_lo_hi - rdwr_en_hi); rdwr_en_lo = min_t(int, rdwr_en_lo, RDWR_EN_LO_CNT__VALUE); @@ -1054,8 +1053,8 @@ static int denali_setup_data_interface(struct mtd_info *mtd, int chipnr, iowrite32(tmp, denali->reg + RDWR_EN_LO_CNT); /* tCS, tCEA -> CS_SETUP_CNT */ - cs_setup = max3((int)DIV_ROUND_UP(timings->tCS_min, t_clk) - rdwr_en_lo, - (int)DIV_ROUND_UP(timings->tCEA_max, t_clk) - acc_clks, + cs_setup = max3((int)DIV_ROUND_UP(timings->tCS_min, t_x) - rdwr_en_lo, + (int)DIV_ROUND_UP(timings->tCEA_max, t_x) - acc_clks, 0); cs_setup = min_t(int, cs_setup, CS_SETUP_CNT__VALUE); @@ -1255,7 +1254,7 @@ int denali_init(struct denali_nand_info *denali) } /* clk rate info is needed for setup_data_interface */ - if (denali->clk_x_rate) + if (denali->clk_rate && denali->clk_x_rate) chip->setup_data_interface = denali_setup_data_interface; ret = nand_scan_ident(mtd, denali->max_banks, NULL); diff --git a/drivers/mtd/nand/raw/denali.h b/drivers/mtd/nand/raw/denali.h index 9ad33d237378..1f8feaf924eb 100644 --- a/drivers/mtd/nand/raw/denali.h +++ b/drivers/mtd/nand/raw/denali.h @@ -300,6 +300,7 @@ struct denali_nand_info { struct nand_chip nand; + unsigned long clk_rate; /* core clock rate */ unsigned long clk_x_rate; /* bus interface clock rate */ int active_bank; /* currently selected bank */ struct device *dev; diff --git a/drivers/mtd/nand/raw/denali_dt.c b/drivers/mtd/nand/raw/denali_dt.c index afaae378c624..0faaad032e5f 100644 --- a/drivers/mtd/nand/raw/denali_dt.c +++ b/drivers/mtd/nand/raw/denali_dt.c @@ -150,6 +150,7 @@ static int denali_dt_probe(struct platform_device *pdev) goto out_disable_clk_x; if (dt->clk_x) { + denali->clk_rate = clk_get_rate(dt->clk); denali->clk_x_rate = clk_get_rate(dt->clk_x); } else { /* @@ -158,6 +159,7 @@ static int denali_dt_probe(struct platform_device *pdev) */ dev_notice(dev, "necessary clock is missing. default clock rates are used.\n"); + denali->clk_rate = 50000000; denali->clk_x_rate = 200000000; } diff --git a/drivers/mtd/nand/raw/denali_pci.c b/drivers/mtd/nand/raw/denali_pci.c index 49cb3e1f8bd0..7c8efc4c7bdf 100644 --- a/drivers/mtd/nand/raw/denali_pci.c +++ b/drivers/mtd/nand/raw/denali_pci.c @@ -73,6 +73,7 @@ static int denali_pci_probe(struct pci_dev *dev, const struct pci_device_id *id) denali->irq = dev->irq; denali->ecc_caps = &denali_pci_ecc_caps; denali->nand.ecc.options |= NAND_ECC_MAXIMIZE; + denali->clk_rate = 50000000; /* 50 MHz */ denali->clk_x_rate = 200000000; /* 200 MHz */ ret = pci_request_regions(dev, DENALI_NAND_NAME); -- 2.45.2