diff options
| -rw-r--r-- | drivers/spi/spi-aspeed-smc.c | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/drivers/spi/spi-aspeed-smc.c b/drivers/spi/spi-aspeed-smc.c index d2b63c8bb88f..35f6934847b7 100644 --- a/drivers/spi/spi-aspeed-smc.c +++ b/drivers/spi/spi-aspeed-smc.c @@ -33,6 +33,8 @@ #define CTRL_IO_ADDRESS_4B BIT(13) /* AST2400 SPI only */ #define CTRL_IO_DUMMY_SET(dummy) \ (((((dummy) >> 2) & 0x1) << 14) | (((dummy) & 0x3) << 6)) +#define CTRL_FREQ_SEL_SHIFT 8 +#define CTRL_FREQ_SEL_MASK GENMASK(11, CTRL_FREQ_SEL_SHIFT) #define CTRL_CE_STOP_ACTIVE BIT(2) #define CTRL_IO_MODE_CMD_MASK GENMASK(1, 0) #define CTRL_IO_MODE_NORMAL 0x0 @@ -45,6 +47,9 @@ /* CEx Address Decoding Range Register */ #define CE0_SEGMENT_ADDR_REG 0x30 +/* CEx Read timing compensation register */ +#define CE0_TIMING_COMPENSATION_REG 0x94 + enum aspeed_spi_ctl_reg_value { ASPEED_SPI_BASE, ASPEED_SPI_READ, @@ -70,10 +75,15 @@ struct aspeed_spi_data { bool hastype; u32 mode_bits; u32 we0; + u32 timing; + u32 hclk_mask; + u32 hdiv_max; u32 (*segment_start)(struct aspeed_spi *aspi, u32 reg); u32 (*segment_end)(struct aspeed_spi *aspi, u32 reg); u32 (*segment_reg)(struct aspeed_spi *aspi, u32 start, u32 end); + int (*calibrate)(struct aspeed_spi_chip *chip, u32 hdiv, + const u8 *golden_buf, u8 *test_buf); }; #define ASPEED_SPI_MAX_NUM_CS 5 @@ -525,6 +535,8 @@ static int aspeed_spi_chip_adjust_window(struct aspeed_spi_chip *chip, return 0; } +static int aspeed_spi_do_calibration(struct aspeed_spi_chip *chip); + static int aspeed_spi_dirmap_create(struct spi_mem_dirmap_desc *desc) { struct aspeed_spi *aspi = spi_controller_get_devdata(desc->mem->spi->master); @@ -573,6 +585,8 @@ static int aspeed_spi_dirmap_create(struct spi_mem_dirmap_desc *desc) chip->ctl_val[ASPEED_SPI_READ] = ctl_val; writel(chip->ctl_val[ASPEED_SPI_READ], chip->ctl); + ret = aspeed_spi_do_calibration(chip); + dev_info(aspi->dev, "CE%d read buswidth:%d [0x%08x]\n", chip->cs, op->data.buswidth, chip->ctl_val[ASPEED_SPI_READ]); @@ -826,6 +840,249 @@ static u32 aspeed_spi_segment_ast2600_reg(struct aspeed_spi *aspi, } /* + * Read timing compensation sequences + */ + +#define CALIBRATE_BUF_SIZE SZ_16K + +static bool aspeed_spi_check_reads(struct aspeed_spi_chip *chip, + const u8 *golden_buf, u8 *test_buf) +{ + int i; + + for (i = 0; i < 10; i++) { + memcpy_fromio(test_buf, chip->ahb_base, CALIBRATE_BUF_SIZE); + if (memcmp(test_buf, golden_buf, CALIBRATE_BUF_SIZE) != 0) { +#if defined(VERBOSE_DEBUG) + print_hex_dump_bytes(DEVICE_NAME " fail: ", DUMP_PREFIX_NONE, + test_buf, 0x100); +#endif + return false; + } + } + return true; +} + +#define FREAD_TPASS(i) (((i) / 2) | (((i) & 1) ? 0 : 8)) + +/* + * The timing register is shared by all devices. Only update for CE0. + */ +static int aspeed_spi_calibrate(struct aspeed_spi_chip *chip, u32 hdiv, + const u8 *golden_buf, u8 *test_buf) +{ + struct aspeed_spi *aspi = chip->aspi; + const struct aspeed_spi_data *data = aspi->data; + int i; + int good_pass = -1, pass_count = 0; + u32 shift = (hdiv - 1) << 2; + u32 mask = ~(0xfu << shift); + u32 fread_timing_val = 0; + + /* Try HCLK delay 0..5, each one with/without delay and look for a + * good pair. + */ + for (i = 0; i < 12; i++) { + bool pass; + + if (chip->cs == 0) { + fread_timing_val &= mask; + fread_timing_val |= FREAD_TPASS(i) << shift; + writel(fread_timing_val, aspi->regs + data->timing); + } + pass = aspeed_spi_check_reads(chip, golden_buf, test_buf); + dev_dbg(aspi->dev, + " * [%08x] %d HCLK delay, %dns DI delay : %s", + fread_timing_val, i / 2, (i & 1) ? 0 : 4, + pass ? "PASS" : "FAIL"); + if (pass) { + pass_count++; + if (pass_count == 3) { + good_pass = i - 1; + break; + } + } else { + pass_count = 0; + } + } + + /* No good setting for this frequency */ + if (good_pass < 0) + return -1; + + /* We have at least one pass of margin, let's use first pass */ + if (chip->cs == 0) { + fread_timing_val &= mask; + fread_timing_val |= FREAD_TPASS(good_pass) << shift; + writel(fread_timing_val, aspi->regs + data->timing); + } + dev_dbg(aspi->dev, " * -> good is pass %d [0x%08x]", + good_pass, fread_timing_val); + return 0; +} + +static bool aspeed_spi_check_calib_data(const u8 *test_buf, u32 size) +{ + const u32 *tb32 = (const u32 *)test_buf; + u32 i, cnt = 0; + + /* We check if we have enough words that are neither all 0 + * nor all 1's so the calibration can be considered valid. + * + * I use an arbitrary threshold for now of 64 + */ + size >>= 2; + for (i = 0; i < size; i++) { + if (tb32[i] != 0 && tb32[i] != 0xffffffff) + cnt++; + } + return cnt >= 64; +} + +static const u32 aspeed_spi_hclk_divs[] = { + 0xf, /* HCLK */ + 0x7, /* HCLK/2 */ + 0xe, /* HCLK/3 */ + 0x6, /* HCLK/4 */ + 0xd, /* HCLK/5 */ +}; + +#define ASPEED_SPI_HCLK_DIV(i) \ + (aspeed_spi_hclk_divs[(i) - 1] << CTRL_FREQ_SEL_SHIFT) + +static int aspeed_spi_do_calibration(struct aspeed_spi_chip *chip) +{ + struct aspeed_spi *aspi = chip->aspi; + const struct aspeed_spi_data *data = aspi->data; + u32 ahb_freq = aspi->clk_freq; + u32 max_freq = chip->clk_freq; + u32 ctl_val; + u8 *golden_buf = NULL; + u8 *test_buf = NULL; + int i, rc, best_div = -1; + + dev_dbg(aspi->dev, "calculate timing compensation - AHB freq: %d MHz", + ahb_freq / 1000000); + + /* + * use the related low frequency to get check calibration data + * and get golden data. + */ + ctl_val = chip->ctl_val[ASPEED_SPI_READ] & data->hclk_mask; + writel(ctl_val, chip->ctl); + + test_buf = kzalloc(CALIBRATE_BUF_SIZE * 2, GFP_KERNEL); + if (!test_buf) + return -ENOMEM; + + golden_buf = test_buf + CALIBRATE_BUF_SIZE; + + memcpy_fromio(golden_buf, chip->ahb_base, CALIBRATE_BUF_SIZE); + if (!aspeed_spi_check_calib_data(golden_buf, CALIBRATE_BUF_SIZE)) { + dev_info(aspi->dev, "Calibration area too uniform, using low speed"); + goto no_calib; + } + +#if defined(VERBOSE_DEBUG) + print_hex_dump_bytes(DEVICE_NAME " good: ", DUMP_PREFIX_NONE, + golden_buf, 0x100); +#endif + + /* Now we iterate the HCLK dividers until we find our breaking point */ + for (i = ARRAY_SIZE(aspeed_spi_hclk_divs); i > data->hdiv_max - 1; i--) { + u32 tv, freq; + + freq = ahb_freq / i; + if (freq > max_freq) + continue; + + /* Set the timing */ + tv = chip->ctl_val[ASPEED_SPI_READ] | ASPEED_SPI_HCLK_DIV(i); + writel(tv, chip->ctl); + dev_dbg(aspi->dev, "Trying HCLK/%d [%08x] ...", i, tv); + rc = data->calibrate(chip, i, golden_buf, test_buf); + if (rc == 0) + best_div = i; + } + + /* Nothing found ? */ + if (best_div < 0) { + dev_warn(aspi->dev, "No good frequency, using dumb slow"); + } else { + dev_dbg(aspi->dev, "Found good read timings at HCLK/%d", best_div); + + /* Record the freq */ + for (i = 0; i < ASPEED_SPI_MAX; i++) + chip->ctl_val[i] = (chip->ctl_val[i] & data->hclk_mask) | + ASPEED_SPI_HCLK_DIV(best_div); + } + +no_calib: + writel(chip->ctl_val[ASPEED_SPI_READ], chip->ctl); + kfree(test_buf); + return 0; +} + +#define TIMING_DELAY_DI BIT(3) +#define TIMING_DELAY_HCYCLE_MAX 5 +#define TIMING_REG_AST2600(chip) \ + ((chip)->aspi->regs + (chip)->aspi->data->timing + \ + (chip)->cs * 4) + +static int aspeed_spi_ast2600_calibrate(struct aspeed_spi_chip *chip, u32 hdiv, + const u8 *golden_buf, u8 *test_buf) +{ + struct aspeed_spi *aspi = chip->aspi; + int hcycle; + u32 shift = (hdiv - 2) << 3; + u32 mask = ~(0xfu << shift); + u32 fread_timing_val = 0; + + for (hcycle = 0; hcycle <= TIMING_DELAY_HCYCLE_MAX; hcycle++) { + int delay_ns; + bool pass = false; + + fread_timing_val &= mask; + fread_timing_val |= hcycle << shift; + + /* no DI input delay first */ + writel(fread_timing_val, TIMING_REG_AST2600(chip)); + pass = aspeed_spi_check_reads(chip, golden_buf, test_buf); + dev_dbg(aspi->dev, + " * [%08x] %d HCLK delay, DI delay none : %s", + fread_timing_val, hcycle, pass ? "PASS" : "FAIL"); + if (pass) + return 0; + + /* Add DI input delays */ + fread_timing_val &= mask; + fread_timing_val |= (TIMING_DELAY_DI | hcycle) << shift; + + for (delay_ns = 0; delay_ns < 0x10; delay_ns++) { + fread_timing_val &= ~(0xf << (4 + shift)); + fread_timing_val |= delay_ns << (4 + shift); + + writel(fread_timing_val, TIMING_REG_AST2600(chip)); + pass = aspeed_spi_check_reads(chip, golden_buf, test_buf); + dev_dbg(aspi->dev, + " * [%08x] %d HCLK delay, DI delay %d.%dns : %s", + fread_timing_val, hcycle, (delay_ns + 1) / 2, + (delay_ns + 1) & 1 ? 5 : 5, pass ? "PASS" : "FAIL"); + /* + * TODO: This is optimistic. We should look + * for a working interval and save the middle + * value in the read timing register. + */ + if (pass) + return 0; + } + } + + /* No good setting for this frequency */ + return -1; +} + +/* * Platform definitions */ static const struct aspeed_spi_data ast2400_fmc_data = { @@ -833,6 +1090,10 @@ static const struct aspeed_spi_data ast2400_fmc_data = { .hastype = true, .we0 = 16, .ctl0 = CE0_CTRL_REG, + .timing = CE0_TIMING_COMPENSATION_REG, + .hclk_mask = 0xfffff0ff, + .hdiv_max = 1, + .calibrate = aspeed_spi_calibrate, .segment_start = aspeed_spi_segment_start, .segment_end = aspeed_spi_segment_end, .segment_reg = aspeed_spi_segment_reg, @@ -843,6 +1104,10 @@ static const struct aspeed_spi_data ast2400_spi_data = { .hastype = false, .we0 = 0, .ctl0 = 0x04, + .timing = 0x14, + .hclk_mask = 0xfffff0ff, + .hdiv_max = 1, + .calibrate = aspeed_spi_calibrate, /* No segment registers */ }; @@ -851,6 +1116,10 @@ static const struct aspeed_spi_data ast2500_fmc_data = { .hastype = true, .we0 = 16, .ctl0 = CE0_CTRL_REG, + .timing = CE0_TIMING_COMPENSATION_REG, + .hclk_mask = 0xffffd0ff, + .hdiv_max = 1, + .calibrate = aspeed_spi_calibrate, .segment_start = aspeed_spi_segment_start, .segment_end = aspeed_spi_segment_end, .segment_reg = aspeed_spi_segment_reg, @@ -861,6 +1130,10 @@ static const struct aspeed_spi_data ast2500_spi_data = { .hastype = false, .we0 = 16, .ctl0 = CE0_CTRL_REG, + .timing = CE0_TIMING_COMPENSATION_REG, + .hclk_mask = 0xffffd0ff, + .hdiv_max = 1, + .calibrate = aspeed_spi_calibrate, .segment_start = aspeed_spi_segment_start, .segment_end = aspeed_spi_segment_end, .segment_reg = aspeed_spi_segment_reg, @@ -872,6 +1145,10 @@ static const struct aspeed_spi_data ast2600_fmc_data = { .mode_bits = SPI_RX_QUAD | SPI_RX_QUAD, .we0 = 16, .ctl0 = CE0_CTRL_REG, + .timing = CE0_TIMING_COMPENSATION_REG, + .hclk_mask = 0xf0fff0ff, + .hdiv_max = 2, + .calibrate = aspeed_spi_ast2600_calibrate, .segment_start = aspeed_spi_segment_ast2600_start, .segment_end = aspeed_spi_segment_ast2600_end, .segment_reg = aspeed_spi_segment_ast2600_reg, @@ -883,6 +1160,10 @@ static const struct aspeed_spi_data ast2600_spi_data = { .mode_bits = SPI_RX_QUAD | SPI_RX_QUAD, .we0 = 16, .ctl0 = CE0_CTRL_REG, + .timing = CE0_TIMING_COMPENSATION_REG, + .hclk_mask = 0xf0fff0ff, + .hdiv_max = 2, + .calibrate = aspeed_spi_ast2600_calibrate, .segment_start = aspeed_spi_segment_ast2600_start, .segment_end = aspeed_spi_segment_ast2600_end, .segment_reg = aspeed_spi_segment_ast2600_reg, |