On Thursday, August 20, 2015 at 07:28:02 AM, Chin Liang See wrote:
Hi,
On Wed, 2015-08-19 at 14:36 +0000, marex@denx.de wrote:
On Wednesday, August 19, 2015 at 10:21:17 AM, Chin Liang See wrote:
Hi,
Hi again,
On Wed, 2015-08-19 at 02:41 +0000, marex@denx.de wrote:
On Wednesday, August 19, 2015 at 07:54:50 AM, Chin Liang See wrote:
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: Pavel Machek pavel@denx.de Cc: Marek Vasut marex@denx.de Cc: Wolfgang Denk wd@denx.de Cc: Stefan Roese sr@denx.de Cc: Tom Rini trini@konsulko.com
drivers/mmc/socfpga_dw_mmc.c | 187
++++++++++++++++++++++++++++++++++++++++-- 1 files changed, 180 insertions(+), 7 deletions(-)
diff --git a/drivers/mmc/socfpga_dw_mmc.c b/drivers/mmc/socfpga_dw_mmc.c index eb69aed..15e537c 100644 --- a/drivers/mmc/socfpga_dw_mmc.c +++ b/drivers/mmc/socfpga_dw_mmc.c @@ -11,25 +11,140 @@
#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) +#define CAL_ROWS 7 +#define CAL_COLS 8
+/*
- 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/18441 0529 + * 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)
{
- unsigned int drvsel;
- unsigned int smplsel;
- /* Structure containing a rectangle candidate */
- typedef struct
- {
unsigned char height;unsigned char width;unsigned short area;- } rect_cand_t;
- /* Array with the rectangle candidates */
- rect_cand_t rect_cands[CAL_ROWS * CAL_COLS];
- unsigned char cr_rect_cand = 0;
- unsigned char height, width, k;
- /* No solution if all combinations fail */
- if(sum == 0)
return 1;- /* 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){
rect_cand_t tmp =
rect_cands[k-1];
rect_cands[k-1] = rect_cands[k];rect_cands[k] = tmp;} elsebreak;}}- }
- /* Try to fit the rectangle candidates, in descending area order
*/ + for(k = 0; k < CAL_ROWS * CAL_COLS; k++) {
unsigned char start_row, start_col;unsigned rect_width = rect_cands[k].width;unsigned rect_height = rect_cands[k].height;/* 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)
&& ok;
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;}}}- }
- /* We could not fit any rectangle - return failure */
- return 1;
Oh btw. please make sure to use errno.h and standard return codes ; -EINVAL in this case I believe.
Good suggestion, will fix in v2. Thanks
Thanks. I was curious, is this really socfpga specific or can this calibration be used on dwmmc in general -- thus on exynos and rockchip systems -- as well? If it's generic to dwmmc, this should be moved into the dwmmc core code. Also, I am CCing Simon, he's been plumbing in the DWMMC recently.
I am not sure. But definitely we can make the calibration common enough if they required the calibration too. Let wait feedback from Simon.
Excellent, thanks!