[PATCH] cpm_uart: Allocate DPRAM memory for SMC ports on CPM2-based platforms.

[Laurent Pinchart <laurentp@cse-semaphore.com>]

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Hi everybody,

the following patch fixes SMC DPRAM handling on CPM2-based platforms. It makes
the cpm_uart driver independent of any SMC initialisation made by the boot
loader. This is required to be able to reset the CPM in cpm2_reset() which
should be the next step in making CPM2 initialisation independent of the
boot loader.

I was concerned this would break udbg, but udbg doesn't seem to be supported
on PQ2-based platforms.

---
This patch allocates parameter RAM for SMC serial ports without relying on
previous initialisation by a boot loader or a wrapper layer.

SMC parameter RAM on CPM2-based platforms can be allocated anywhere in the
general-purpose areas of the dual-port RAM. The current code relies on the
boot loader to allocate a section of general-purpose CPM RAM and gets the
section address from the device tree.

This patch modifies the device tree address usage to reference the SMC
parameter RAM base pointer instead of a pre-allocated RAM section and
allocates memory from the CPM dual-port RAM when initialising the SMC port.
CPM1-based platforms are not affected.

Signed-off-by: Laurent Pinchart <laurentp@cse-semaphore.com>
---
 drivers/serial/cpm_uart/cpm_uart.h      |    3 ++
 drivers/serial/cpm_uart/cpm_uart_core.c |   19 +++++++--------
 drivers/serial/cpm_uart/cpm_uart_cpm1.c |   12 ++++++++++
 drivers/serial/cpm_uart/cpm_uart_cpm2.c |   37 +++++++++++++++++++++++++++++++
 4 files changed, 61 insertions(+), 10 deletions(-)

diff --git a/drivers/serial/cpm_uart/cpm_uart.h b/drivers/serial/cpm_uart/cpm_uart.h
index 80a7d60..5334653 100644
--- a/drivers/serial/cpm_uart/cpm_uart.h
+++ b/drivers/serial/cpm_uart/cpm_uart.h
@@ -93,6 +93,9 @@ extern struct uart_cpm_port cpm_uart_ports[UART_NR];
 
 /* these are located in their respective files */
 void cpm_line_cr_cmd(struct uart_cpm_port *port, int cmd);
+void __iomem *cpm_uart_map_pram(struct uart_cpm_port *port,
+				struct device_node *np);
+void cpm_uart_unmap_pram(struct uart_cpm_port *port, void __iomem *pram);
 int cpm_uart_init_portdesc(void);
 int cpm_uart_allocbuf(struct uart_cpm_port *pinfo, unsigned int is_con);
 void cpm_uart_freebuf(struct uart_cpm_port *pinfo);
diff --git a/drivers/serial/cpm_uart/cpm_uart_core.c b/drivers/serial/cpm_uart/cpm_uart_core.c
index af875ad..56f39ca 100644
--- a/drivers/serial/cpm_uart/cpm_uart_core.c
+++ b/drivers/serial/cpm_uart/cpm_uart_core.c
@@ -997,24 +997,23 @@ static int cpm_uart_init_port(struct device_node *np,
 	if (!mem)
 		return -ENOMEM;
 
-	pram = of_iomap(np, 1);
-	if (!pram) {
-		ret = -ENOMEM;
-		goto out_mem;
-	}
-
 	if (of_device_is_compatible(np, "fsl,cpm1-scc-uart") ||
 	    of_device_is_compatible(np, "fsl,cpm2-scc-uart")) {
 		pinfo->sccp = mem;
-		pinfo->sccup = pram;
+		pinfo->sccup = pram = cpm_uart_map_pram(pinfo, np);
 	} else if (of_device_is_compatible(np, "fsl,cpm1-smc-uart") ||
 	           of_device_is_compatible(np, "fsl,cpm2-smc-uart")) {
 		pinfo->flags |= FLAG_SMC;
 		pinfo->smcp = mem;
-		pinfo->smcup = pram;
+		pinfo->smcup = pram = cpm_uart_map_pram(pinfo, np);
 	} else {
 		ret = -ENODEV;
-		goto out_pram;
+		goto out_mem;
+	}
+
+	if (!pram) {
+		ret = -ENOMEM;
+		goto out_mem;
 	}
 
 	pinfo->tx_nrfifos = TX_NUM_FIFO;
@@ -1038,7 +1037,7 @@ static int cpm_uart_init_port(struct device_node *np,
 	return cpm_uart_request_port(&pinfo->port);
 
 out_pram:
-	iounmap(pram);
+	cpm_uart_unmap_pram(pinfo, pram);
 out_mem:
 	iounmap(mem);
 	return ret;
diff --git a/drivers/serial/cpm_uart/cpm_uart_cpm1.c b/drivers/serial/cpm_uart/cpm_uart_cpm1.c
index 52fb044..060f566 100644
--- a/drivers/serial/cpm_uart/cpm_uart_cpm1.c
+++ b/drivers/serial/cpm_uart/cpm_uart_cpm1.c
@@ -58,6 +58,18 @@ void cpm_line_cr_cmd(struct uart_cpm_port *port, int cmd)
 	while (in_be16(cpcr) & CPM_CR_FLG)
 		;
 }
+
+void __iomem *cpm_uart_map_pram(struct uart_cpm_port *port,
+				struct device_node *np)
+{
+	return of_iomap(np, 1);
+}
+
+void cpm_uart_unmap_pram(struct uart_cpm_port *port, void __iomem *pram)
+{
+	iounmap(pram);
+}
+
 #else
 void cpm_line_cr_cmd(struct uart_cpm_port *port, int cmd)
 {
diff --git a/drivers/serial/cpm_uart/cpm_uart_cpm2.c b/drivers/serial/cpm_uart/cpm_uart_cpm2.c
index 88daad1..9391dc6 100644
--- a/drivers/serial/cpm_uart/cpm_uart_cpm2.c
+++ b/drivers/serial/cpm_uart/cpm_uart_cpm2.c
@@ -41,6 +41,9 @@
 #include <asm/io.h>
 #include <asm/irq.h>
 #include <asm/fs_pd.h>
+#ifdef CONFIG_PPC_CPM_NEW_BINDING
+#include <asm/prom.h>
+#endif
 
 #include <linux/serial_core.h>
 #include <linux/kernel.h>
@@ -60,6 +63,40 @@ void cpm_line_cr_cmd(struct uart_cpm_port *port, int cmd)
 
 	cpm2_unmap(cp);
 }
+
+void __iomem *cpm_uart_map_pram(struct uart_cpm_port *port,
+				struct device_node *np)
+{
+	void __iomem *pram;
+	unsigned long offset;
+
+	/* Don't remap parameter RAM if it has already been initialized
+	 * during console setup.
+	 */
+	if (IS_SMC(port) && port->smcup)
+		return port->smcup;
+	else if (!IS_SMC(port) && port->sccup)
+		return port->sccup;
+
+	pram = of_iomap(np, 1);
+	if (!pram)
+		return NULL;
+
+	if (!IS_SMC(port))
+		return pram;
+
+	offset = cpm_dpalloc(PROFF_SMC_SIZE, 64);
+	out_be16(pram, offset);
+	iounmap(pram);
+	return cpm_muram_addr(offset);
+}
+
+void cpm_uart_unmap_pram(struct uart_cpm_port *port, void __iomem *pram)
+{
+	if (!(port->flags & FLAG_SMC))
+		iounmap(pram);
+}
+
 #else
 void cpm_line_cr_cmd(struct uart_cpm_port *port, int cmd)
 {
-- 
1.5.0


-- 
Laurent Pinchart
CSE Semaphore Belgium

Chaussée de Bruxelles, 732A
B-1410 Waterloo
Belgium

T +32 (2) 387 42 59
F +32 (2) 387 42 75

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