Patchwork [U-Boot,v2] powerpc: fix 8xx and 82xx type-punning warnings with GCC 4.7

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Submitter Scott Wood
Date May 18, 2013, 1:01 a.m.
Message ID <20130518010154.GA28787@home.buserror.net>
Download mbox | patch
Permalink /patch/244720/
State Accepted
Delegated to: Wolfgang Denk
Headers show

Comments

Scott Wood - May 18, 2013, 1:01 a.m.
C99's strict aliasing rules are insane to use in low-level code such as a
bootloader, but as Wolfgang has rejected -fno-strict-aliasing in the
past, add a union so that 16-bit accesses can be performed.

Compile-tested only.

Signed-off-by: Scott Wood <scottwood@freescale.com>
---
v2:
 - Use sizeof(u16) instead of 2.
 - Define PROFF_REVNUM for 8xx (not strictly related, but requested by
   Wolfgang).
 - Don't rely on in_be16 to evade the compiler's type-punning checks.
   Use in_be16 if and only if the existing code used it.

 arch/powerpc/cpu/mpc8260/commproc.c        |    2 +-
 arch/powerpc/cpu/mpc8260/cpu.c             |    2 +-
 arch/powerpc/cpu/mpc8260/i2c.c             |    8 ++++----
 arch/powerpc/cpu/mpc8260/serial_smc.c      |    4 ++--
 arch/powerpc/cpu/mpc8260/spi.c             |    2 +-
 arch/powerpc/cpu/mpc8xx/cpu.c              |   12 ++++++++----
 arch/powerpc/include/asm/8xx_immap.h       |    7 ++++++-
 arch/powerpc/include/asm/immap_8260.h      |   19 ++++++++++++-------
 common/cmd_immap.c                         |    2 +-
 examples/standalone/mem_to_mem_idma2intr.c |    3 ++-
 include/commproc.h                         |    1 +
 11 files changed, 39 insertions(+), 23 deletions(-)
Wolfgang Denk - May 22, 2013, 9:15 p.m.
Dear Scott Wood,

In message <20130518010154.GA28787@home.buserror.net> you wrote:
> C99's strict aliasing rules are insane to use in low-level code such as a
> bootloader, but as Wolfgang has rejected -fno-strict-aliasing in the
> past, add a union so that 16-bit accesses can be performed.
> 
> Compile-tested only.
> 
> Signed-off-by: Scott Wood <scottwood@freescale.com>

Thanks!

Acked-by: Wolfgang Denk <wd@denx.de>

Best regards,

Wolfgang Denk

Patch

diff --git a/arch/powerpc/cpu/mpc8260/commproc.c b/arch/powerpc/cpu/mpc8260/commproc.c
index 22cef3e..484bd17 100644
--- a/arch/powerpc/cpu/mpc8260/commproc.c
+++ b/arch/powerpc/cpu/mpc8260/commproc.c
@@ -43,7 +43,7 @@  m8260_cpm_reset(void)
 	} while ((immr->im_cpm.cp_cpcr & CPM_CR_FLG) && ++count < 1000000);
 
 #ifdef CONFIG_HARD_I2C
-	*((unsigned short*)(&immr->im_dprambase[PROFF_I2C_BASE])) = 0;
+	immr->im_dprambase16[PROFF_I2C_BASE / sizeof(u16)] = 0;
 #endif
 }
 
diff --git a/arch/powerpc/cpu/mpc8260/cpu.c b/arch/powerpc/cpu/mpc8260/cpu.c
index f8bc5a9..22e1a23 100644
--- a/arch/powerpc/cpu/mpc8260/cpu.c
+++ b/arch/powerpc/cpu/mpc8260/cpu.c
@@ -106,7 +106,7 @@  int checkcpu (void)
 	 * in the mask.
 	 */
 	m = immr & (IMMR_PARTNUM_MSK | IMMR_MASKNUM_MSK);
-	k = *((ushort *) & immap->im_dprambase[PROFF_REVNUM]);
+	k = immap->im_dprambase16[PROFF_REVNUM / sizeof(u16)];
 
 	switch (m) {
 	case 0x0000:
diff --git a/arch/powerpc/cpu/mpc8260/i2c.c b/arch/powerpc/cpu/mpc8260/i2c.c
index b720b1f..e2341e9 100644
--- a/arch/powerpc/cpu/mpc8260/i2c.c
+++ b/arch/powerpc/cpu/mpc8260/i2c.c
@@ -221,14 +221,14 @@  void i2c_init(int speed, int slaveadd)
 	i2c_init_board();
 #endif
 
-	dpaddr = *((unsigned short *) (&immap->im_dprambase[PROFF_I2C_BASE]));
+	dpaddr = immap->im_dprambase16[PROFF_I2C_BASE / sizeof(u16)];
 	if (dpaddr == 0) {
 		/* need to allocate dual port ram */
 		dpaddr = m8260_cpm_dpalloc(64 +
 					(NUM_RX_BDS * sizeof(I2C_BD)) +
 					(NUM_TX_BDS * sizeof(I2C_BD)) +
 					MAX_TX_SPACE, 64);
-		*((unsigned short *)(&immap->im_dprambase[PROFF_I2C_BASE])) =
+		immap->im_dprambase16[PROFF_I2C_BASE / sizeof(u16)] =
 			dpaddr;
 	}
 
@@ -305,7 +305,7 @@  void i2c_newio(i2c_state_t *state)
 
 	debug("[I2C] i2c_newio\n");
 
-	dpaddr = *((unsigned short *)(&immap->im_dprambase[PROFF_I2C_BASE]));
+	dpaddr = immap->im_dprambase16[PROFF_I2C_BASE / sizeof(u16)];
 	iip = (iic_t *)&immap->im_dprambase[dpaddr];
 	state->rx_idx = 0;
 	state->tx_idx = 0;
@@ -480,7 +480,7 @@  int i2c_doio(i2c_state_t *state)
 		return I2CERR_QUEUE_EMPTY;
 	}
 
-	dpaddr = *((unsigned short *)(&immap->im_dprambase[PROFF_I2C_BASE]));
+	dpaddr = immap->im_dprambase16[PROFF_I2C_BASE / sizeof(u16)];
 	iip = (iic_t *)&immap->im_dprambase[dpaddr];
 	iip->iic_rbptr = iip->iic_rbase;
 	iip->iic_tbptr = iip->iic_tbase;
diff --git a/arch/powerpc/cpu/mpc8260/serial_smc.c b/arch/powerpc/cpu/mpc8260/serial_smc.c
index feba1f6..9410e4c 100644
--- a/arch/powerpc/cpu/mpc8260/serial_smc.c
+++ b/arch/powerpc/cpu/mpc8260/serial_smc.c
@@ -105,7 +105,7 @@  static int mpc8260_smc_serial_init(void)
 	/* initialize pointers to SMC */
 
 	sp = (smc_t *) &(im->im_smc[SMC_INDEX]);
-	*(ushort *)(&im->im_dprambase[PROFF_SMC_BASE]) = PROFF_SMC;
+	im->im_dprambase16[PROFF_SMC_BASE / sizeof(u16)] = PROFF_SMC;
 	up = (smc_uart_t *)&im->im_dprambase[PROFF_SMC];
 
 	/* Disable transmitter/receiver. */
@@ -331,7 +331,7 @@  kgdb_serial_init (void)
 	/* initialize pointers to SMC */
 
 	sp = (smc_t *) &(im->im_smc[KGDB_SMC_INDEX]);
-	*(ushort *)(&im->im_dprambase[KGDB_PROFF_SMC_BASE]) = KGDB_PROFF_SMC;
+	im->im_dprambase16[KGDB_PROFF_SMC_BASE / sizeof(u16)] = KGDB_PROFF_SMC;
 	up = (smc_uart_t *)&im->im_dprambase[KGDB_PROFF_SMC];
 
 	/* Disable transmitter/receiver. */
diff --git a/arch/powerpc/cpu/mpc8260/spi.c b/arch/powerpc/cpu/mpc8260/spi.c
index dc98ea7..01b492e 100644
--- a/arch/powerpc/cpu/mpc8260/spi.c
+++ b/arch/powerpc/cpu/mpc8260/spi.c
@@ -146,7 +146,7 @@  void spi_init_f (void)
 	immr = (immap_t *)  CONFIG_SYS_IMMR;
 	cp   = (cpm8260_t *) &immr->im_cpm;
 
-	*(ushort *)(&immr->im_dprambase[PROFF_SPI_BASE]) = PROFF_SPI;
+	immr->im_dprambase16[PROFF_SPI_BASE / sizeof(u16)] = PROFF_SPI;
 	spi  = (spi_t *)&immr->im_dprambase[PROFF_SPI];
 
 /* 1 */
diff --git a/arch/powerpc/cpu/mpc8xx/cpu.c b/arch/powerpc/cpu/mpc8xx/cpu.c
index b6b733d..dc33eb3 100644
--- a/arch/powerpc/cpu/mpc8xx/cpu.c
+++ b/arch/powerpc/cpu/mpc8xx/cpu.c
@@ -78,7 +78,8 @@  static int check_CPU (long clock, uint pvr, uint immr)
 	if ((pvr >> 16) != 0x0050)
 		return -1;
 
-	k = (immr << 16) | *((ushort *) & immap->im_cpm.cp_dparam[0xB0]);
+	k = (immr << 16) |
+		immap->im_cpm.cp_dparam16[PROFF_REVNUM / sizeof(u16)];
 	m = 0;
 	suf = "";
 
@@ -194,7 +195,8 @@  static int check_CPU (long clock, uint pvr, uint immr)
 	if ((pvr >> 16) != 0x0050)
 		return -1;
 
-	k = (immr << 16) | *((ushort *) & immap->im_cpm.cp_dparam[0xB0]);
+	k = (immr << 16) |
+		immap->im_cpm.cp_dparam16[PROFF_REVNUM / sizeof(u16)];
 	m = 0;
 
 	switch (k) {
@@ -253,7 +255,8 @@  static int check_CPU (long clock, uint pvr, uint immr)
 	if ((pvr >> 16) != 0x0050)
 		return -1;
 
-	k = (immr << 16) | in_be16((ushort *)&immap->im_cpm.cp_dparam[0xB0]);
+	k = (immr << 16) |
+		in_be16(&immap->im_cpm.cp_dparam16[PROFF_REVNUM / sizeof(u16)]);
 	m = 0;
 
 	switch (k) {
@@ -312,7 +315,8 @@  static int check_CPU (long clock, uint pvr, uint immr)
 	if ((pvr >> 16) != 0x0050)
 		return -1;
 
-	k = (immr << 16) | *((ushort *) & immap->im_cpm.cp_dparam[0xB0]);
+	k = (immr << 16) |
+		immap->im_cpm.cp_dparam16[PROFF_REVNUM / sizeof(u16)];
 	m = 0;
 
 	switch (k) {
diff --git a/arch/powerpc/include/asm/8xx_immap.h b/arch/powerpc/include/asm/8xx_immap.h
index 40679cb..01129ed 100644
--- a/arch/powerpc/include/asm/8xx_immap.h
+++ b/arch/powerpc/include/asm/8xx_immap.h
@@ -485,7 +485,12 @@  typedef struct comm_proc {
 	 * Some processors don't have all of it populated.
 	 */
 	u_char	cp_dpmem[0x1C00];	/* BD / Data / ucode */
-	u_char	cp_dparam[0x400];	/* Parameter RAM */
+
+	/* Parameter RAM */
+	union {
+		u_char	cp_dparam[0x400];
+		u16	cp_dparam16[0x200];
+	};
 } cpm8xx_t;
 
 /* Internal memory map.
diff --git a/arch/powerpc/include/asm/immap_8260.h b/arch/powerpc/include/asm/immap_8260.h
index 4974ae5..c7021a7 100644
--- a/arch/powerpc/include/asm/immap_8260.h
+++ b/arch/powerpc/include/asm/immap_8260.h
@@ -526,13 +526,18 @@  typedef struct immap {
 	/* Some references are into the unique and known dpram spaces,
 	 * others are from the generic base.
 	 */
-#define im_dprambase	im_dpram1
-	u_char		im_dpram1[16*1024];
-	char		res1[16*1024];
-	u_char		im_dpram2[4*1024];
-	char		res2[8*1024];
-	u_char		im_dpram3[4*1024];
-	char		res3[16*1024];
+	union {
+		struct {
+			u_char		im_dpram1[16 * 1024];
+			char		res1[16 * 1024];
+			u_char		im_dpram2[4 * 1024];
+			char		res2[8 * 1024];
+			u_char		im_dpram3[4 * 1024];
+			char		res3[16 * 1024];
+		};
+		u8	im_dprambase[64 * 1024];
+		u16	im_dprambase16[32 * 1024];
+	};
 
 	sysconf8260_t	im_siu_conf;	/* SIU Configuration */
 	memctl8260_t	im_memctl;	/* Memory Controller */
diff --git a/common/cmd_immap.c b/common/cmd_immap.c
index fdf9489..bb15795 100644
--- a/common/cmd_immap.c
+++ b/common/cmd_immap.c
@@ -535,7 +535,7 @@  do_i2cinfo (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 	volatile iic_t *iip;
 	uint dpaddr;
 
-	dpaddr = *((unsigned short *) (&immap->im_dprambase[PROFF_I2C_BASE]));
+	dpaddr = immap->im_dprambase16[PROFF_I2C_BASE / sizeof(u16)];
 	if (dpaddr == 0)
 		iip = NULL;
 	else
diff --git a/examples/standalone/mem_to_mem_idma2intr.c b/examples/standalone/mem_to_mem_idma2intr.c
index e466c90..215dc22 100644
--- a/examples/standalone/mem_to_mem_idma2intr.c
+++ b/examples/standalone/mem_to_mem_idma2intr.c
@@ -309,7 +309,8 @@  int idma_init (void)
 
 	memaddr = dpalloc (sizeof (pram_idma_t), 64);
 
-	*(volatile ushort *) &immap->im_dprambase[PROFF_IDMA2_BASE] = memaddr;
+	*(volatile u16 *)&immap->im_dprambase16
+		[PROFF_IDMA2_BASE / sizeof(u16)] = memaddr;
 	piptr = (volatile pram_idma_t *) ((uint) (immap) + memaddr);
 
 	piptr->pi_resv1 = 0;		/* manual says: clear it */
diff --git a/include/commproc.h b/include/commproc.h
index 7ca28c8..6959905 100644
--- a/include/commproc.h
+++ b/include/commproc.h
@@ -127,6 +127,7 @@  typedef struct cpm_buf_desc {
 */
 #define PROFF_SCC1	((uint)0x0000)
 #define PROFF_IIC	((uint)0x0080)
+#define PROFF_REVNUM	((uint)0x00b0)
 #define PROFF_SCC2	((uint)0x0100)
 #define PROFF_SPI	((uint)0x0180)
 #define PROFF_SCC3	((uint)0x0200)