fix(rpi3): initialize SD card host controller

Add initial configuration parameters for Rasperry Pi 3's sdhost
controller, and then configure and use those parameters.

This change allows warm reboots of UEFI on Raspberry Pi 3B+ where
existing code often fails with "unknown error". See discussion at:

https://github.com/pftf/RPi3/issues/24

The basic idea is that some initial configuration parameters
(clock rate, bus width) aren't configured into the hardware before
commands start being sent. I suspect that the particular setting
that matters is the "slow card" bit, but the initial clock setting
also seemed wrong to me.

Change-Id: I526def340def143f23f3422f1fc14c12c937ca7f
Signed-off-by: Rob Newberry <robthedude@mac.com>

drivers/rpi3/sdhost/rpi3_sdhost.c

@@ -245,13 +245,12 @@ static void rpi3_sdhost_reset(void)
 
 static void rpi3_sdhost_initialize(void)
 {
-	uintptr_t reg_base = rpi3_sdhost_params.reg_base;
-
 	assert((rpi3_sdhost_params.reg_base & MMC_BLOCK_MASK) == 0);
 
 	rpi3_sdhost_reset();
 
-	mmio_write_32(reg_base + HC_CLOCKDIVISOR, HC_CLOCKDIVISOR_PREFERVAL);
+	rpi3_sdhost_set_ios(rpi3_sdhost_params.clk_rate_initial,
+		rpi3_sdhost_params.bus_width);
 	udelay(300);
 }
 

include/drivers/rpi3/sdhost/rpi3_sdhost.h

@@ -15,6 +15,7 @@
 struct rpi3_sdhost_params {
 	uintptr_t	reg_base;
 	uint32_t	clk_rate;
+	uint32_t	clk_rate_initial;
 	uint32_t	bus_width;
 	uint32_t        flags;
 	uint32_t	current_cmd;
@@ -57,6 +58,8 @@ void rpi3_sdhost_stop(void);
 #define HC_CMD_READ			0x0040
 #define HC_CMD_COMMAND_MASK		0x003f
 
+#define RPI3_SDHOST_MAX_CLOCK		250000000	// technically, we should obtain this number from the mailbox
+
 #define HC_CLOCKDIVISOR_MAXVAL		0x07ff
 #define HC_CLOCKDIVISOR_PREFERVAL	0x027b
 #define HC_CLOCKDIVISOR_SLOWVAL		0x0148

plat/rpi/rpi3/rpi3_bl2_setup.c

@@ -35,7 +35,9 @@ static void rpi3_sdhost_setup(void)
 	params.reg_base = RPI3_SDHOST_BASE;
 	params.bus_width = MMC_BUS_WIDTH_1;
 	params.clk_rate = 50000000;
+	params.clk_rate_initial = (RPI3_SDHOST_MAX_CLOCK / HC_CLOCKDIVISOR_MAXVAL);
 	mmc_info.mmc_dev_type = MMC_IS_SD_HC;
+	mmc_info.ocr_voltage = OCR_3_2_3_3 | OCR_3_3_3_4;
 	rpi3_sdhost_init(&params, &mmc_info);
 }