mmc: stm32_sdmmc2: manage max-frequency property from DT

If the max-frequency property is provided in the device tree mmc node,
it should be managed. The max allowed frequency will be the min between
this property value and what the card can support.

Change-Id: I885b676c3300d2670a0fe4c6ecab87758b5893ad
Signed-off-by: Yann Gautier <yann.gautier@st.com>

drivers/st/mmc/stm32_sdmmc2.c

@@ -152,10 +152,14 @@ bool plat_sdmmc2_use_dma(unsigned int instance, unsigned int memory)
 static void stm32_sdmmc2_init(void)
 {
 	uint32_t clock_div;
+	uint32_t freq = STM32MP_MMC_INIT_FREQ;
 	uintptr_t base = sdmmc2_params.reg_base;
 
-	clock_div = div_round_up(sdmmc2_params.clk_rate,
-				 STM32MP_MMC_INIT_FREQ * 2);
+	if (sdmmc2_params.max_freq != 0U) {
+		freq = MIN(sdmmc2_params.max_freq, freq);
+	}
+
+	clock_div = div_round_up(sdmmc2_params.clk_rate, freq * 2U);
 
 	mmio_write_32(base + SDMMC_CLKCR, SDMMC_CLKCR_HWFC_EN | clock_div |
 		      sdmmc2_params.negedge |
@@ -406,7 +410,7 @@ static int stm32_sdmmc2_set_ios(unsigned int clk, unsigned int width)
 {
 	uintptr_t base = sdmmc2_params.reg_base;
 	uint32_t bus_cfg = 0;
-	uint32_t clock_div, max_freq;
+	uint32_t clock_div, max_freq, freq;
 	uint32_t clk_rate = sdmmc2_params.clk_rate;
 	uint32_t max_bus_freq = sdmmc2_params.device_info->max_bus_freq;
 
@@ -438,7 +442,13 @@ static int stm32_sdmmc2_set_ios(unsigned int clk, unsigned int width)
 		}
 	}
 
-	clock_div = div_round_up(clk_rate, max_freq * 2);
+	if (sdmmc2_params.max_freq != 0U) {
+		freq = MIN(sdmmc2_params.max_freq, max_freq);
+	} else {
+		freq = max_freq;
+	}
+
+	clock_div = div_round_up(clk_rate, freq * 2U);
 
 	mmio_write_32(base + SDMMC_CLKCR,
 		      SDMMC_CLKCR_HWFC_EN | clock_div | bus_cfg |
@@ -692,6 +702,11 @@ static int stm32_sdmmc2_dt_get_config(void)
 		}
 	}
 
+	cuint = fdt_getprop(fdt, sdmmc_node, "max-frequency", NULL);
+	if (cuint != NULL) {
+		sdmmc2_params.max_freq = fdt32_to_cpu(*cuint);
+	}
+
 	return 0;
 }
 

include/drivers/st/stm32_sdmmc2.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2018, STMicroelectronics - All Rights Reserved
+ * Copyright (c) 2017-2019, STMicroelectronics - All Rights Reserved
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -22,6 +22,7 @@ struct stm32_sdmmc2_params {
 	unsigned int		dirpol;
 	unsigned int		clock_id;
 	unsigned int		reset_id;
+	unsigned int		max_freq;
 	bool			use_dma;
 };