[POWERPC] cpm-serial: Relocate CPM buffer descriptors and SMC parameter ram.

This patch relocates the buffer descriptors and the SMC parameter RAM at the
end of the first CPM muram chunk, as described in the device tree. This allows
device trees to stop excluding SMC parameter ram allocated by the boot loader
from the CPM muram node.

Signed-off-by: Laurent Pinchart <laurentp@cse-semaphore.com>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/Kconfig.debug

@@ -269,7 +269,7 @@ config PPC_EARLY_DEBUG_CPM_ADDR
 	hex "CPM UART early debug transmit descriptor address"
 	depends on PPC_EARLY_DEBUG_CPM
 	default "0xfa202008" if PPC_EP88XC
-	default "0xf0000008" if CPM2
+	default "0xf0001ff8" if CPM2
 	default "0xff002008" if CPM1
 	help
 	  This specifies the address of the transmit descriptor

arch/powerpc/boot/cpm-serial.c

@@ -11,6 +11,7 @@
 #include "types.h"
 #include "io.h"
 #include "ops.h"
+#include "page.h"
 
 struct cpm_scc {
 	u32 gsmrl;
@@ -42,6 +43,22 @@ struct cpm_param {
 	u16 tbase;
 	u8 rfcr;
 	u8 tfcr;
+	u16 mrblr;
+	u32 rstate;
+	u8 res1[4];
+	u16 rbptr;
+	u8 res2[6];
+	u32 tstate;
+	u8 res3[4];
+	u16 tbptr;
+	u8 res4[6];
+	u16 maxidl;
+	u16 idlc;
+	u16 brkln;
+	u16 brkec;
+	u16 brkcr;
+	u16 rmask;
+	u8 res5[4];
 };
 
 struct cpm_bd {
@@ -54,10 +71,10 @@ static void *cpcr;
 static struct cpm_param *param;
 static struct cpm_smc *smc;
 static struct cpm_scc *scc;
-struct cpm_bd *tbdf, *rbdf;
+static struct cpm_bd *tbdf, *rbdf;
 static u32 cpm_cmd;
-static u8 *muram_start;
-static u32 muram_offset;
+static void *cbd_addr;
+static u32 cbd_offset;
 
 static void (*do_cmd)(int op);
 static void (*enable_port)(void);
@@ -119,20 +136,25 @@ static int cpm_serial_open(void)
 
 	out_8(&param->rfcr, 0x10);
 	out_8(&param->tfcr, 0x10);
-
-	rbdf = (struct cpm_bd *)muram_start;
-	rbdf->addr = (u8 *)(rbdf + 2);
+	out_be16(&param->mrblr, 1);
+	out_be16(&param->maxidl, 0);
+	out_be16(&param->brkec, 0);
+	out_be16(&param->brkln, 0);
+	out_be16(&param->brkcr, 0);
+
+	rbdf = cbd_addr;
+	rbdf->addr = (u8 *)rbdf - 1;
 	rbdf->sc = 0xa000;
 	rbdf->len = 1;
 
 	tbdf = rbdf + 1;
-	tbdf->addr = (u8 *)(rbdf + 2) + 1;
+	tbdf->addr = (u8 *)rbdf - 2;
 	tbdf->sc = 0x2000;
 	tbdf->len = 1;
 
 	sync();
-	out_be16(&param->rbase, muram_offset);
-	out_be16(&param->tbase, muram_offset + sizeof(struct cpm_bd));
+	out_be16(&param->rbase, cbd_offset);
+	out_be16(&param->tbase, cbd_offset + sizeof(struct cpm_bd));
 
 	do_cmd(CPM_CMD_INIT_RX_TX);
 
@@ -175,9 +197,12 @@ static unsigned char cpm_serial_getc(void)
 
 int cpm_console_init(void *devp, struct serial_console_data *scdp)
 {
-	void *reg_virt[2];
-	int is_smc = 0, is_cpm2 = 0, n;
+	void *vreg[2];
+	u32 reg[2];
+	int is_smc = 0, is_cpm2 = 0;
 	void *parent, *muram;
+	void *muram_addr;
+	unsigned long muram_offset, muram_size;
 
 	if (dt_is_compatible(devp, "fsl,cpm1-smc-uart")) {
 		is_smc = 1;
@@ -201,19 +226,18 @@ int cpm_console_init(void *devp, struct serial_console_data *scdp)
 	else
 		do_cmd = cpm1_cmd;
 
-	n = getprop(devp, "fsl,cpm-command", &cpm_cmd, 4);
-	if (n < 4)
+	if (getprop(devp, "fsl,cpm-command", &cpm_cmd, 4) < 4)
 		return -1;
 
-	if (dt_get_virtual_reg(devp, reg_virt, 2) < 2)
+	if (dt_get_virtual_reg(devp, vreg, 2) < 2)
 		return -1;
 
 	if (is_smc)
-		smc = reg_virt[0];
+		smc = vreg[0];
 	else
-		scc = reg_virt[0];
+		scc = vreg[0];
 
-	param = reg_virt[1];
+	param = vreg[1];
 
 	parent = get_parent(devp);
 	if (!parent)
@@ -227,17 +251,40 @@ int cpm_console_init(void *devp, struct serial_console_data *scdp)
 		return -1;
 
 	/* For bootwrapper-compatible device trees, we assume that the first
-	 * entry has at least 18 bytes, and that #address-cells/#data-cells
+	 * entry has at least 128 bytes, and that #address-cells/#data-cells
 	 * is one for both parent and child.
 	 */
 
-	if (dt_get_virtual_reg(muram, (void **)&muram_start, 1) < 1)
+	if (dt_get_virtual_reg(muram, &muram_addr, 1) < 1)
 		return -1;
 
-	n = getprop(muram, "reg", &muram_offset, 4);
-	if (n < 4)
+	if (getprop(muram, "reg", reg, 8) < 8)
 		return -1;
 
+	muram_offset = reg[0];
+	muram_size = reg[1];
+
+	/* Store the buffer descriptors at the end of the first muram chunk.
+	 * For SMC ports on CPM2-based platforms, relocate the parameter RAM
+	 * just before the buffer descriptors.
+	 */
+
+	cbd_offset = muram_offset + muram_size - 2 * sizeof(struct cpm_bd);
+
+	if (is_cpm2 && is_smc) {
+		u16 *smc_base = (u16 *)param;
+		u16 pram_offset;
+
+		pram_offset = cbd_offset - 64;
+		pram_offset = _ALIGN_DOWN(pram_offset, 64);
+
+		disable_port();
+		out_be16(smc_base, pram_offset);
+		param = muram_addr - muram_offset + pram_offset;
+	}
+
+	cbd_addr = muram_addr - muram_offset + cbd_offset;
+
 	scdp->open = cpm_serial_open;
 	scdp->putc = cpm_serial_putc;
 	scdp->getc = cpm_serial_getc;