Enable SDMMC calibration to determine the best setting for drvsel and smpsel. It will be triggered whenever there is a change of card frequency and bus width. This is to ensure reliable transmission between the controller and the card.

Signed-off-by: Chin Liang See clsee@altera.com Cc: Dinh Nguyen dinguyen@opensource.altera.com Cc: Dinh Nguyen dinh.linux@gmail.com Cc: Pavel Machek pavel@denx.de Cc: Marek Vasut marex@denx.de Cc: Stefan Roese sr@denx.de Cc: Pantelis Antoniou pantelis.antoniou@konsulko.com Cc: Simon Glass sjg@chromium.org Cc: Jaehoon Chung jh80.chung@samsung.com --- Changes for v3 - Remove the && ok as its redundant Changes for v2 - Using standard error return macro - Split to small function to avoid deep identation - Fix coding standard --- drivers/mmc/socfpga_dw_mmc.c | 198 ++++++++++++++++++++++++++++++++++++++++-- 1 files changed, 191 insertions(+), 7 deletions(-)

diff --git a/drivers/mmc/socfpga_dw_mmc.c b/drivers/mmc/socfpga_dw_mmc.c index 8076761..2161f694 100644 --- a/drivers/mmc/socfpga_dw_mmc.c +++ b/drivers/mmc/socfpga_dw_mmc.c @@ -13,25 +13,150 @@ #include <asm/arch/dwmmc.h> #include <asm/arch/clock_manager.h> #include <asm/arch/system_manager.h> +#include "mmc_private.h"

static const struct socfpga_clock_manager *clock_manager_base = (void *)SOCFPGA_CLKMGR_ADDRESS; static const struct socfpga_system_manager *system_manager_base = (void *)SOCFPGA_SYSMGR_ADDRESS;

-static void socfpga_dwmci_clksel(struct dwmci_host *host) +/* + * rows and columns of calibration rectange. The values are based on the value + * range of drvsel and smplsel register in system manager + */ +#define CAL_ROWS 7 +#define CAL_COLS 8 + +int find_row_col_fit_rectangle(unsigned rect_width, unsigned rect_height, +unsigned char cal_results[CAL_ROWS][CAL_COLS], unsigned int *cal_row, +unsigned int *cal_col) { - unsigned int drvsel; - unsigned int smplsel; + unsigned char start_row, start_col; + + /* Find the row and column where the candidate fits */ + for (start_col = 0; start_col < (CAL_COLS - rect_width + 1); + start_col++) { + for (start_row = 0; start_row < (CAL_ROWS - rect_height + 1); + start_row++) { + unsigned ok = 1; + unsigned add_col, add_row; + + /* Determine if the rectangle fits here */ + for (add_col = 0; (add_col < rect_width); add_col++) { + for (add_row = 0; add_row < rect_height; + add_row++) { + if (!cal_results[start_row + add_row] + [start_col + add_col]) { + ok = 0; + break; + } + } + } + + /* + * Return 'middle' of rectangle in case of + * success + */ + if (ok) { + if (rect_width > 1) + rect_width--; + + if (rect_height > 1) + rect_height--;

+ *cal_row = start_row + (rect_height / 2); + *cal_col = start_col + (rect_width / 2); + + return 0; + } + } + } + return -EINVAL; +} + +/* + * This function determines the largest rectangle filled with 1's and returns + * the middle. This functon can be optimized, for example using the algorithm + * from http://www.drdobbs.com/database/the-maximal-rectangle-problem/184410529 + * It currently takes less than 1ms, while creating the input data takes ~5ms + * so there is not a real need to optimize it. + */ +int find_calibration_point(unsigned char cal_results[CAL_ROWS][CAL_COLS], +unsigned int sum, unsigned int *cal_row, unsigned int *cal_col) +{ + /* Structure containing a rectangle candidate */ + struct rect_cand_t { + unsigned char height; + unsigned char width; + unsigned short area; + }; + + /* Array with the rectangle candidates */ + struct rect_cand_t rect_cands[CAL_ROWS * CAL_COLS], tmp; + unsigned char cr_rect_cand = 0; + unsigned char height, width, k; + + /* No solution if all combinations fail */ + if (sum == 0) + return -EINVAL; + + /* Simple solution if all combinations pass */ + if (sum == (CAL_ROWS * CAL_COLS)) { + *cal_row = (CAL_ROWS - 1) / 2; + *cal_col = (CAL_COLS - 1) / 2; + return 0; + } + + /* + * Create list of all possible sub-rectangles, in descending area + * order + */ + for (height = CAL_ROWS; height >= 1; height--) { + for (width = CAL_COLS; width >= 1; width--) { + /* Add a new rectangle candidate */ + rect_cands[cr_rect_cand].height = height; + rect_cands[cr_rect_cand].width = width; + rect_cands[cr_rect_cand].area = height * width; + cr_rect_cand++; + + /* First candidate it always in the right position */ + if (cr_rect_cand == 1) + continue; + + /* + * Put the candidate in right location to maintain + * descending order + */ + for (k = cr_rect_cand - 1; k > 1; k--) { + if (rect_cands[k-1].area < rect_cands[k].area) { + tmp = rect_cands[k-1]; + rect_cands[k-1] = rect_cands[k]; + rect_cands[k] = tmp; + } else { + break; + } + } + } + } + + /* Try to fit the rectangle candidates, in descending area order */ + for (k = 0; k < CAL_ROWS * CAL_COLS; k++) { + if (!find_row_col_fit_rectangle(rect_cands[k].width, + rect_cands[k].height, + cal_results, cal_row, cal_col)) + return 0; + } + + /* We could not fit any rectangle - return failure */ + return -EINVAL; +} + +static void socfpga_dwmmc_set_clksel(unsigned int drvsel, unsigned int smplsel) +{ /* Disable SDMMC clock. */ clrbits_le32(&clock_manager_base->per_pll.en, CLKMGR_PERPLLGRP_EN_SDMMCCLK_MASK);

- /* Configures drv_sel and smpl_sel */ - drvsel = CONFIG_SOCFPGA_DWMMC_DRVSEL; - smplsel = CONFIG_SOCFPGA_DWMMC_SMPSEL; - debug("%s: drvsel %d smplsel %d\n", __func__, drvsel, smplsel); writel(SYSMGR_SDMMC_CTRL_SET(smplsel, drvsel), &system_manager_base->sdmmcgrp_ctrl); @@ -44,6 +169,65 @@ static void socfpga_dwmci_clksel(struct dwmci_host *host) CLKMGR_PERPLLGRP_EN_SDMMCCLK_MASK); }

+/* + * This functions calirates the drvsel and smplsel by trying all possible + * values and selecting the best combnation + */ +void socfpga_dwmmc_calibrate(struct dwmci_host *host) +{ + int err = 0; + unsigned char cal_results[CAL_ROWS][CAL_COLS]; + unsigned int sum = 0; + unsigned int row, col, drvsel, smplsel; + + struct mmc *mmc = (struct mmc *)host->mmc; + if (mmc == NULL) { + printf("struct mmc is NULL\n"); + hang(); + } + + debug("%s: Calibration started.\n", __func__); + + for (row = 0; row < CAL_ROWS; row++) { + for (col = 0; col < CAL_COLS; col++) { + drvsel = row + 1; + smplsel = col; + socfpga_dwmmc_set_clksel(drvsel, smplsel); + cal_results[row][col] = !(mmc_set_blocklen(mmc, + mmc->read_bl_len)); + sum += cal_results[row][col]; + } + } + + debug("%s: Calibration raw data:\n", __func__); + for (row = 0; row < CAL_ROWS; row++) { + debug("\t"); + for (col = 0; col < CAL_COLS; col++) + debug("%d ", cal_results[row][col]); + debug("\n"); + } + + err = find_calibration_point(cal_results, sum, &drvsel, &smplsel); + + if (err) { + printf("%s: Calibration failed.\n", __func__); + hang(); + } else + debug("%s: Calibration passed: drvsel = %d " + "smplsel = %d.\n", __func__, drvsel, smplsel); + + socfpga_dwmmc_set_clksel(drvsel, smplsel); + + /* re-write in case accidentally overwrite with junk */ + mmc_set_blocklen(mmc, mmc->read_bl_len); +} + +void socfpga_dwmci_clksel(struct dwmci_host *host) +{ + socfpga_dwmmc_calibrate(host); +} + + static int socfpga_dwmci_of_probe(const void *blob, int node, const int idx) { /* FIXME: probe from DT eventually too/ */